Conservation and utilization of sweet potato genetic …...Conservation and V. Ramanatha Rao and...

Conservation and

V. Ramanatha Rao and Michael Hermann (editors)

utilization of sweetpotato geneticdiversity in Asia

Proceedings of 2nd Asian Network forSweetpotato Genetic Resources3–5 November 1999, Bogor, Indonesia

Proceedings of training course cum workshop10–17 May 1998, Kunming and Xishuangbanna, Yunnan, China

IPGRI is an institute ofthe Consultative Groupon InternationalAgricultural Research(CGIAR)

Conservation andutilization of sweetpotato geneticdiversity in Asia

Proceedings of 2nd Asian Network forSweetpotato Genetic Resources,3–5 November 1999, Bogor, Indonesia

V. Ramanatha Rao and Michael Hermann (editors)

Hosted by:International Potato Center (CIP), Regional for East,Southeast Asia and the Pacific (ESEAP)Kebun Percabaan MuaraJl. Raya Ciapus, Bogar 16610Indonesia

Sponsored by:International Plant Genetic Resources Institute (IPGRI)

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The International Plant Genetic Resources Institute (IPGRI) is an autonomous internationalscientific organization, supported by the Consultative Group on International AgriculturalResearch (CGIAR). IPGRI’s mandate is to advance the conservation and use of geneticdiversity for the well-being of present and future generations. IPGRI’s headquarters is basedin Rome, Italy, with offices in another 19 countries worldwide. It operates through threeprogrammes: (1) the Plant Genetic Resources Programme, (2) the CGIAR Genetic ResourcesSupport Programme, and (3) the International Network for the Improvement of Bananaand Plantain (INIBAP).

The international status of IPGRI is conferred under an Establishment Agreement which,by January 2000, had been signed and ratified by the Governments of Algeria, Australia,Belgium, Benin, Bolivia, Brazil, Burkina Faso, Cameroon, Chile, China, Congo, Costa Rica,Côte d’Ivoire, Cyprus, Czech Republic, Denmark, Ecuador, Egypt, Greece, Guinea, Hungary,India, Indonesia, Iran, Israel, Italy, Jordan, Kenya, Malaysia, Mauritania, Morocco, Norway,Pakistan, Panama, Peru, Poland, Portugal, Romania, Russia, Senegal, Slovakia, Sudan,Switzerland, Syria, Tunisia, Turkey, Uganda and Ukraine.

Financial support for the Research Agenda of IPGRI is provided by the Governmentsof Australia, Austria, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Cyprus, CzechRepublic, Denmark, Estonia, F.R. Yugoslavia (Serbia and Montenegro), Finland, France,Germany, Greece, Hungary, Iceland, India, Ireland, Israel, Italy, Japan, Republic of Korea, Latvia,Lithuania, Luxembourg, Macedonia (F.Y.R.), Malta, Mexico, the Netherlands, Norway, Peru,the Philippines, Poland, Portugal, Romania, Slovakia, Slovenia, South Africa, Spain, Sweden,Switzerland, Turkey, the UK, the USA and by the Asian Development Bank, Common Fundfor Commodities, Technical Centre for Agricultural and Rural Cooperation (CTA), EuropeanEnvironment Agency (EEA), European Union, Food and Agriculture Organization of the UnitedNations (FAO), International Development Research Centre (IDRC), International Fund forAgricultural Development (IFAD), Interamerican Development Bank, Natural ResourcesInstitute (NRI), Centre de coopération internationale en recherché agronomique pour ledéveloppement (CIRAD), Nordic Genebank, Rockefeller Foundation, United NationsDevelopment Programme (UNDP), United Nations Environment Programme (UNEP), TaiwanBanana Research Institute (TBRI) and the World Bank.

The geographical designations employed and the presentation of material in this publicationdo not imply the expression of any opinion whatsoever on the part of IPGRI or the CGIARconcerning the legal status of any country, territory, city or area or its authorities, or concerningthe delimitation of its frontiers or boundaries. Similarly, the views expressed are those ofthe authors and do not necessarily reflect the views of these participating organizations.

Citation: Ramanatha Rao and Michael Hermann, editors. 2001. Conservation and Utilizationof Sweetpotato Genetic Diversity in Asia - Proceedings of the Asian Network for SweetpotatoGenetic Resources Workshop, 3-5 November 1999, Bogor, Indonesia. IPGRI-APO, Serdang,Malaysia

ISBN 92-9043-467-8

IPGRI Regional Office for Asia, the Pacific and OceaniaUPM Campus, Serdang, 43400 Selangor Darul Ehsan, Malaysia© International Plant Genetic Resources Institute, 2001

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Contents

Foreword v

The ANSWER Network: a CIP Statement 1Gordon Prain

Summary of the Proceedings 3Michael Hermann

Sweetpotato Germplasm Conservation and Breeding in the 6Department of Agriculture, Sri Lanka

P.S.A.D. Premathilake

Sweetpotato Germplasm Conservation Activities in Universiti 9Putra Malaysia, Malaysia

M.S. Saad

In Vitro Conservation of Sweetpotato Germplasm 16Guo Xiaoding, Zhou Ming-De and Wang Yi

Present Status of Sweetpotato Germplasm Conservation in Indonesia 25M. Jusuf, St.A.Rahayuningsih and Minantiyorini

Conservation and Documentation of Sweetpotato Genetic Resources 34in Irian Jaya

Ery Atmojo

Sweetpotato Germplasm Conservation and Breeding in CIP-ESEAP 39Tjintokohadi, N.L. Ningsih and Il Gin Mok

Recent Progress on the Conservation and Use of Sweetpotato 47in the Philippines

Algerico M. Mariscal, Jose L. Bacusmo, Villaluz Z. Acedo and Enrique Abogadie

Conservation and Use of Sweetpotato in Thailand 53Narin Poolperm

Status of Conservation and Use of Sweetpotato Germplasm in Vietnam 58Luu Ngoc Trinh, Bui Tuyet Mai and Nguyen Ngoc Hue

Recent Progress in the Conservation and Use of Sweetpotato 63Germplasm in India

S.K. Naskar, C.S. Easwari Amma and S.G. Nair

Appendix 1. Programme 68

Appendix 2. List of Participants 70

Appendix 3. Summary Tables from Group Discussions 72

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Foreword

Sweetpotato is a post-Colombian introduction into Asia. However, over years of cultivationin varied agroclimatic conditions of the vast region, significant genetic diversity is nowavailable and the need for collecting, conserving and using this diversity was recognizedaround 1993–94. A dialogue between the International Centre for Potato (CIP) and theInternational Plant Genetic Resources Institute (IPGRI) on enhancing collaboration amongthe sweetpotato workers in Asia was initiated at the end of 1993. During 1994–95, a draftconcept paper on “collaboration for the conservation of sweetpotato biodiversity in Asiaand the Pacific” was prepared jointly by Dr Schmiediche of CIP-Bogor and Dr RamanathaRao of IPGRI-APO. This was circulated within CIP and IPGRI. Based on the commentsreceived, the concept note was finalized in 1995–96. It attracted much attention from a numberof countries in the region. This led to the organization of a joint meeting with CIP in Bogor,Indonesia, in May 1996 which led to the formation of the Asia Network on SweetpotatoGenetic Resources (ANSWER) with 11 partner countries. The proceedings of the meetingwere published by IPGRI and were widely disseminated. Initially it was agreed that IPGRI-APO would provide secretariat assistance to ANSWER.

During 1996–1999, several activities were undertaken by partners under the auspicesof ANSWER, supported by CIP, IPGRI and the Government of Japan. Such activitiesincluded genetic diversity research, training on maintenance, characterization andduplicate identification and rationalization of collections in field genebanks.

Changes to ANSWER in 1999

Members of the ANSWER network (except those from Japan and PNG) met in Bogor alongwith CIP and IPGRI representatives on November 2–5, 1999, in order to discuss the furtherdevelopment of the network. The objectives of this meeting were mainly to review progressin sweetpotato germplasm conservation since last meeting; identify priority problems anddevelop a plan for a regional project, with emphasis on coordinated actions and sharedresources; define project outputs, responsibilities and funding needs and define governanceand management of ANSWER activities. The proceedings that have been put together jointlyby CIP and IPGRI indicate that much has been achieved on the objectives set for the meeting.An important outcome of the meeting is the agreement on the role of CIP in the governanceof the Network which would lead to its increased role in conservation and use of sweetpotatogermplsm in Asia and that of IPGRI which will continue to provide technical and scientificbackstopping to ANSWER. This collaboration represents a good model for inter-CGIARCentre collaboration together with national partners in utilizing existing resources to meetidentified needs for plant genetic resources of a particular crop in the region.

These proceedings have been compiled and edited based on the papers presentedat this workshop, dealing with objectives as set by ANSWER members. They containthe information on the progress made during the three years since the members metlast time, but more importantly they record the commitments made by different partnersfor furthering sweetpotato genetic resources work in Asia. They also contain therecommendations on strategies and approaches proposed at the workshop, which willform the basis for future work of ANSWER. It is my hope that the publication anddistribution of this volume will stimulate further the already vigorous activity insweetpotato genetic resources conservation and use in the region.

Percy SajiseRegional DirectorIPGRI Office for Asia, Pacific and Oceania

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The ANSWER Network: a CIP Statement

Gordon PrainCIP, ESEAP regional representative (currently project leader, SIUPA, System-wideInitiative for Urban and Peri-urban Agriculture)

Since the founding meeting of ANSWER in 1996 there has been a growing interest inthe issue of conserving sweetpotato genetic resources in the region. This has partlybeen stimulated by a general growth in interest at the international level in crop geneticresources and has increased the visibility and coherence of the CGIAR’s approachthrough the System-wide Genetic Resources Program and SINGER, co-ordinated byIPGRI. But it has also been the result of several activities concerned specifically withimproving the representativeness and efficiency of ex situ conservation of sweetpotato,understanding better the characteristics of sweetpotato diversity in genebanks and infarmers’ fields and exploring the potential uses of collected material through betterevaluation.

Examples of these activities include the meeting in the Philippines in early 1997sponsored by the Japanese Government, which explored recent experiences insweetpotato genetic conservation and breeding and examined the feasibility ofdeveloping action plans for future collaborative work (Prain 1998). A follow-up to thatmeeting was the training course jointly organized by IPGRI and CIP in September 1997to share approaches and methods to conservation and documentation among specialistsin the region. At the same time, CIP spearheaded a regional documentation ofsweetpotato genebanks as part of the broader IPGRI-SINGER.

In Indonesia, the period from 1997 up to the present has seen an intensive effortto improve documentation methods for ex situ conservation (Jusuf et al. 1998). This workhas led to the production of a CD-ROM of Indonesian sweetpotato (Prain and Hermann2001), which it is hoped will be a model for documentation of other genebanks withinthe network. Inter-institutional and interdisciplinary teams in Indonesia and thePhilippines have also been assessing in situ conservation during this period with results,which may be valuable for other countries (Prain and Bagalanon 1998;Yaku andWidyastuti1998; Prain and Campilan 1999; Prain et al. 2000). Increased interest has alsobeen evident in China to step up collection efforts in areas underrepresented in thegermplasm collections in Xuzhou. In early 1998 genetic resources specialists in Vietnamjoined an IPGRI-coordinated global project on in situ conservation of crop geneticdiversity and have begun to develop considerable skills and experience in this fieldin the following two years. Though sweetpotato is not one of the targeted crops in thein situ project, taro is included and the Vietnamese specialists involved also haveresponsibility for sweetpotato. There are thus very good opportunities for transferringthe experiences with taro to sweetpotato conservation in Vietnam and hopefully, tothe entire Asian region.

These activities have so far been mainly the result of independent initiatives bynational systems, CIP, IPGRI and the Japanese Government rather than outputs of theANSWER network. Lack of funds has undoubtedly limited the extent to which thenetworking aims of the 1996 meeting could have been met. Attempts to remedy thatsituation began in 1998 when a new draft proposal for the continuation of the ANSWERnetwork was prepared and shared amongst ANSWER members. There may also havebeen some lack of clarity from the first meeting about alternative options for the network,given variable availability of resources.

2 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA

The Second ANSWER meeting reported here has been important for two mainreasons. The papers presented at the meeting and now collected in this volume areexcellent testimony to the growing interest and capacity in the region for sweetpotatogenetic resources research referred to at the beginning of this statement. Second, themeeting gave particular attention to the issue of flexible response to different levelsof available resources. This has meant that a programme of action was determined andhas already been implemented. In particular, an ANSWER website has been established(http://www.eseap.cipotato.org/ANSWER/index.htm) and first steps to pool databaseshave been undertaken.

In closing I would like to pay tribute to the dedication of the genetic resourcesspecialists from ANSWER member countries and to the way in which, through theseveral meetings which have taken place since its inauguration, you are fast developinginto a collaborative genetic resources partnership. I would also like to thank IPGRI,through Dr Ramanatha Rao, for the extremely important support they have continuedto give ANSWER during the past three years. The support to the sweetpotato geneticresources training course, the ANSWER review meeting reported here and thepublication of these Proceedings are an important example of another partnership:international genetic resources collaboration between CIP as a commodity centre andIPGRI, in support of national crop conservation efforts.

ReferencesJusuf, M., St.A. Rahayuningsih, Minantyorini, and I.G. Mok. 1998. Sweetpotato breeding

and conservation in Indonesia. Pp. 49–62 in Sweetpotato Genetic ResourcesConservation and Use in Asia, Proceedings of MAFF-PRCETC InternationalWorkshop (R.L. Tatala-Sanico, ed.) MAFF, Tsukuba, Japan.

Mok, I.G. and P. Schmiediche. 1999. Collecting, characterizing and maintaining sweetpotatogermplasm in Indonesia. Plant Genetic Resources Newsletter 118:12-18.

Prain, G.1998. The potential for on-farm conservation of rootcrop germplasm in thePhilippines. Pp.11–36 in Sweetpotato Genetic Resources – Conservation and Usein Asia (R.L. Tatala-Sanico, ed.). MAFF/PRCRTC, Philippines.

Prain, G. and C.P. Bagalanon. 1998. Conservation and Change: Farmer Managementof Agricultural Biodiversity in the Context of Development. UPWARD, Laguna.

Prain, G. and D. Campilan. 1999. Farmer Maintenance of Sweetpotato Diversity in Asia:Dominant Cultivars and Implications for In Situ Conservation. Impact on a ChangingWorld, CIP, Peru.

Prain, G. and M. Hermann (eds.). 2001. A Guide to Indonesian Sweetpotato Diversity.CD-ROM, CIP, ANSWER.

Prain, G., J. Schneider and C. Widiyastuti. 2000. Farmer’s maintenance of sweetpotatodiversity in Irian Jaya. Pp. 54–59 in Encouraging Diversity – The Conservation andDevelopment of Plant Genetic Resources, (Almekinders Conny and De Boef Walter,eds.). Intermediate Technology, London.

Yaku, A. and C. Widyastuti. 1998. Tapping sweetpotato and taro genetic resources forsustainable livelihood in Irian Jaya. Pp.73–80 in Sustainable Livelihood for RuralHouseholds: Contributions from Rootcrop Agriculture (UPWARD, ed.). UPWARD,Philippines.

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Summary of the Proceedings

Michael HermannCIP

Members of the ANSWER network (Asian Network for Sweetpotato Genetic Resources)from China, India, Indonesia, Malaysia, Philippines, Sri Lanka, Thailand and Vietnam,met in Bogor along with CIP and IPGRI representatives, on 2–5 November 1999, inorder to discuss the further development of the network. Members from Japan andPapua New Guinea could not attend.

Objectives

• The meeting had the following objectives:• Review progress in sweetpotato germplasm conservation by ANSWER participants

since last meeting• Take stock of sweetpotato holdings in the region and develop a plan for ANSWER

database• Identify priority problems of sweetpotato conservation in the ANSWER region• Develop a plan for a regional sweetpotato conservation project, with emphasis on

coordinated actions and shared resources• Define project outputs, responsibilities and funding requirements• Define priorities for funding proposal development• Define governance and management of ANSWER activities• Further consider the possibility of sweetpotato conservation through botanical seeds.

Dr M. Jusuf, ANSWER chairman, opened the meeting in the morning of November3, and Dr Gordon Prain (CIP) and Dr Ramanatha Rao (IPGRI) delivered welcomeaddresses. The rest of the first day was reserved for presentations of member scientists(see appended programme). This was a valuable exercise to bring participants up todate with each other ’s progress and to set the stage for the following two days’deliberations.

Problem identification and prioritization

On the second and third day, we used elements of the Participatory Project Planningmethodology, particularly the “card method”. Participants wrote down ideas and conceptson cards, which were pinned on a wall, discussed, reformulated, rearranged and so forth.

The first exercise was to identify problems in relation to sweetpotato germplasmconservation in Asia. This provided a good sense for the scope of persisting problems,which were grouped into larger thematic areas. The following groups emerged:• Lack of, or inadequate, conservation strategies (cost reduction, priority material,

guideline development)• Clonal duplicates• Lack of funding (donor fatigue, lack of commitment, etc.)• Inadequate information and germplasm exchange• Insufficient public awareness• Insufficient database management (coordination, standards, gaps, fragmentation of

efforts)• Geographical and other gaps in collections• Size of collections (core approach)


• Insufficient germplasm utilization (impact)• Management problems (various)• Maintenance of problematic material (poorly adapted, late maturing, non-flowering,

non-tuberizing).

The participants then split into two groups, each dealing with a subset of theseproblem areas and charged with the development of a matrix, which would restatethe problems and find complementary outputs and activities for project implementation.The purpose of this exercise was to identify priorities for action of a regional sweetpotatoconservation project emphasizing coordination between members and shared resources.The following areas (or components) of future ANSWER projects were identified (inorder of priority):• Strengthening the network• Information and germplasm exchange• Training• Increased germplasm utilization• Impact studies• Complementary conservation (seeds, in situ)• Characterization• Regional sweetpotato genebank (back-up facility).

Since ANSWER lacked an appropriate level of activities in its previous phase, exceptfor some activities in Malaysia and the Philippines supported by IPGRI, and given theuncertainty of fund-raising, the group agreed that it should give thought to activitiesthat could be implemented immediately. Ideally, such activities would not require largeamounts of external funding, but would provide ANSWER with coherence and bettervisibility.

The following activities were identified as priorities for action with little or noexternal funding:1. It was agreed to establish an ANSWER web page on the CIP-Bogor server. Mr

Sukendra Mahalaya, CIP information management officer, in consultation with thenewly elected ANSWER Coordinator is expected to implement the web page notmuch later than December 1999.

2. Inventory germplasm related information of ANSWER members and document inappropriate form. Establish minimum data sets for an ANSWER germplasmdatabase, the first version of which should become available by the end of 2000and be linked to the ANSWER web page. Ideally, this database should allow forqueries, perhaps using the tool kits offered by SINGER. Initially, the database shouldmake available passport data (allowing mapping) but later also characterizationdata. Prof Gerry Mariscal (Philippines), Mr Tjintokohadi (CIP, ESEAP) and DrMichael Hermann (CIP, Lima) were requested to team up as a task force to implementthis. CIP agreed to provide a clearing-house mechanism for database consolidationand the definition of data standards.

3. IPGRI agreed to assist ANSWER with the translation of sweetpotato research materialin Chinese, such as the ones on in vitro technology and “artificial seed”, which wasof great interest to the members.

4. Dr Ramanatha Rao (IPGRI) also agreed to take the initiative with the publicationof the proceedings of the meeting. He raised the possibility that, funds permitting,IPGRI might contribute to that publication in 2000.

Dr Michael Hermann (CIP, Lima) committed to take the initiative with proposaldevelopment for external funding of ANSWER. The group felt that it would be mostappropriate to seek incremental funding from different donors (e.g. foundations) for

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components of the ANSWER agenda. That mode would hopefully allow for diversifiedinvestment in ANSWER and ensure focus on priorities while attenuating emphasis ofthe network character of activities, which “fatigued” donors do not view too favourably.Dr Hermann will get back to the ANSWER Coordinator and members with drafts fortheir comments.

Governance

The group then deliberated about governance and membership of ANSWER. Whilerecognizing that ANSWER came into being as an unanticipated result of the 1996meeting, by the initiative of very active members, and that it needed to maintain agood deal of informality, it was felt that membership needed to be “regulated”. Alsoto make sure that there would be more interaction between members, an ANSWERCoordinator needed to be appointed. ANSWER’s network character was reaffirmed asopposed to a project mode.

First, the group confirmed the terms of reference for the newly created ANSWERCoordinator:• Appointed among ANSWER members by election for a minimum period of two

years• Can be re-elected during ANSWER meetings• Coordinate activities of ANSWER drawing on support from the ANSWER Secretariat• Organize a bi-yearly meeting• Appoint task forces among the members as needed• Report activities and financial issues during network meetings.

Upon request by the members and IPGRI, CIP agreed to serve as ANSWER secretariatand to provide modest financial support for communications by the ANSWERCoordinator. It was agreed that IPGRI would continue to provide technical andnetworking support, and would be a member and advisor to ANSWER.

The following requirements for ANSWER membership were endorsed:• Individuals or institutions directly involved in sweetpotato germplasm conservation

and utilization• Represent an Asian country where sweetpotato is an important crop or is recognized

as a priority crop by the government (for production or R&D)• Relevant individuals need to be designated by their institutions• Multiple membership (sweetpotato institutions) per country possible, but as far as

possible, should be avoided as members might be required to play representationalrole

• Members who are not, or no longer, actively involved in sweetpotato germplasmconservation should not be appointed as their institutions’ representatives or resignfrom the task.

CIP and IPGRI will be non-voting members of ANSWER.Finally, Prof Algerico Mariscal, from the Philippine Rootcrop Research and Training

Centre (PRCRTC), accepted the unanimous nomination to serve as the future ANSWERCoordinator. The meeting closed on a vote of thanks to Dr M. Jusuf, RILET, Indonesia,the outgoing chairman, who has successfully steered the network through its first threeyears.


Sweetpotato Germplasm Conservation and Breeding in theDepartment of Agriculture, Sri Lanka

P.S.A.D. PremathilakeHorticultural Crop Research Institute, Gannoruwa, Peradeniya, Sri Lanka

Introduction

Sweetpotato is a crop of exotic origin, but people regard it as indigenous since it hasbeen in cultivation in Sri Lanka as an important traditional food crop from very ancienttimes. It was an integral part of the poor man’s crop in subsistence farming, now onits way to become a market-oriented crop. In Sri Lanka, sweetpotato can be cultivatedthroughout the year in different growing situations (rice fallow, land, open highland,river valley basin, homestead, partial shade) in all agroecological zones (De Silva andPremathilake 1985).

The present annual extent under sweetpotato is 9040 hectares and annual productionis 85 882 metric tones. In 1996, the average yield was 6.6 t/ha and at present it is 9.5 t/ha.It is estimated that per capita availability of sweetpotato is 4.3 kg/yr.

Germplasm collection

The sweetpotato genetic resources in the country are diverse. Genetic materials collectedto build up a germplasm bank include local varieties, introductions and breeding lines.However, with the natural calamities some of the genetic resources became extinct ormissing. The Department of Agriculture (DOA) has collected and maintainedsweetpotato genetic resources in the field genebank and in the laboratory in the formof tissue culture. The Horticultural Crop Research Institute maintains the field genebankand the Plant Genetic Resources Centre maintains in vitro collection.

Crop improvement programme

The general objective of the crop improvement programme is to produce varieties havingcharacters desired by user groups. The specific objectives are high yield, high dry mattercontent, low sugar content, short crop duration, good eating quality and acceptablepost harvest losses.

The basic step in any crop improvement programme is to create genetic variability.In sweetpotato, genetic variability is created through conventional methods and non-conventional methods. The conventional methods are collecting of germplasm,introductions, selective hybridization and polycross breeding.

DOA has recommended six (Wariyapola Red, CARI-9, CARI-273, CARI-426,Ranabima and Wariyapola, a white high yielding 20–24 t/ha) sweetpotato varieties forgeneral cultivation and two varieties (Shanthi and Chithra) for low-lying situationsunder wet zone (12–16 t/ha). As a result of combined superior genotypes existing inthe germplasm collection through selective hybridisation, CARI-9 and CARI-273 wereidentified. As sweetpotato is an insect pollinated species, polycross breeding enhancesthe genetic variability for faster crop improvement by minimizing the breeding problemsencountered with sweetpotato. The sweetpotato varieties, namely CARI-426 andRanabima, are creditable products of polycross breeding in sweetpotato. The WariyapolaWhite is a creditable product of natural mutation and Wariyapola Red, Shanthi andChithra are natural selections from the native germplasm collection.

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Improved sweetpotato varieties developed in Sri Lanka were not widely adoptedby farmers because they were generated based on the researchers’ criteria withoutconsideration of the end users’ needs. Yield, resistance and agronomic traits wereconsidered important by researchers while qualitative traits were considered as moreimportant by users. Therefore user participation in variety selection of sweetpotato wasstarted. This showed that users would readily adopt the new clones.

Current status

Genetic resources of sweetpotato from within and outside the country have beencollected to build up a germplasm bank. Now 135 accessions of sweetpotato, whichconsist of 55 local clones, 39 introductions and 41 breeding lines, are maintained inthe field genebank. Evaluation of these genetic resources has revealed that there is abroad variability in root yield, maturity, quality and agronomic characters. The PlantGenetic Resources Centre (PGRC) is maintaining 85 accessions in vitro.

Sweetpotato can be grown throughout the year in Sri Lanka. But it is mainly grownwith the southwest (Yala) and northeast (Maha) monsoon rains. If irrigation water isavailable it can be grown throughout the year. The germplasm accessions are replantedtwice a year in the field genebank. The accessions are planted in mounds 90c.m aparthaving 5 stem cuttings per mound. Losses are observed in the field genebank throughcontinuous replanting.

Current number of accessions with passport data, morphologicalcharacterization and evaluation data

Recommended varieties, pre-released varieties and some local varieties have passportdata and morphological characterization data. These are kept in files and not in acomputerised database. Evaluation data are available for recommended varieties andpre-released varieties.

Number of accessions with farmers’ knowledge

Most farmers grow the local recommended sweetpotato variety Wariyapola Red. Thefarmers know the local varieties and the recommended varieties. Non-availability ofplanting material of recommended varieties is a problem for the spread of the varieties.Establishment of large-scale cultivation of improved varieties on farmers’ fields andgovernment farms can overcome this constraint.

Establishment of a germplasm collection

There are many reasons for the establishment of a germplasm collection. In many casesa germplasm collection is needed for the crop improvement programme. Plant breedersrequire genetically diverse material to develop improved crop varieties. The more diversethe gene pool, the higher is the probability that it would contain desirable genes.Germplasm collection is needed to conserve endangered species. Further it is neededto conserve for future requirements.


Problems and constraints of field genebank management

Maintenance of vegetative materials in the field is vulnerable to many losses. Therefore,field genebank management has the following problems:• High cost of maintenance in terms of land, supplies and labour• Biotic constraints (weevil/nematode/diseases, recycling of vines, decaying own and

other crop residues, inter- and intraspecies competition) and abiotic constraints(excessive moisture, occasional drought, high temperature, soil acidity and alkalinity,soil compaction and poor aeration)

• Duplicates continue to be maintained adding to cost• Gradual loss of true-to-type germplasm due to mixtures between accessions in the

collection• Lack of financial support.

Future plans

• Characterization of all sweetpotato varieties• Removal of duplicates• Sharing of information related to field genebank management• Exchange of sweetpotato germplasm with other countries• Clean-up of material.

ReferencesDe Silva, K.P.U and A. Premathilake.1995. Screening of sweetpotato genotypes in rice-

fallow environments. Incorporation of users’ criteria in variety development ofsweetpotato. Selected Research Papers 1994/95wl. 2: Sweetpotato, 1-7. SAPPRAD,Philippines.

De Silva, K.P.U and A. Premathilake.1988. Performance of promising sweetpotato lines,CARI –426, developed through polycross breeding. Proceedings of the Sri LankaAssociation for Advancement of Science 44(1).

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Sweetpotato Germplasm Conservation Activities in Universiti PutraMalaysia, Malaysia

M.S. SaadPGRC, Institute of Bioscience, UPM, Serdang, Malaysia

Introduction

Sweetpotato is planted in a rather small acreage in Malaysia. In 1998, the total areaplanted with sweetpotato in Peninsular Malaysia was 2070 hectares (MOA 1999).However, due its potential as a source of food, in 1995 the crop was listed in the prioritylist of the Malaysian Intensified Research in Priority Areas programme. Since then severalinstitutions have started research and development programmes on sweetpotato. Amongthem are the Malaysian Agricultural Research and Development Institute (MARDI),the Department of Agriculture (DOA) and Universiti Putra Malaysia (UPM).

Sweetpotato R&D programme in UPM was started in 1983 at the UPM SarawakCampus. In 1987, the programme was moved to the Faculty of Agriculture, UPM maincampus in Serdang, Selangor, Malaysia. Sweetpotato germplasm conservation activityat UPM has been going on since 1983. All the germplasm are now being kept at thePlant Genetic Resources Centre (PGRC), UPM. This paper reports the current statusof the sweetpotato germplasm conservation in UPM.


Table 1 lists the sweetpotato germplasm being maintained at the PGRC. To date, thetotal number of sweetpotato germplasm maintained at the PGRC is 217. The numberis much smaller as compared to the total number of germplasm collected or received.Many of them were lost due to pest attack, especially virus and mycoplasma. However,a few of them were identified as duplicates and discarded.

Table 1. The numbers and locations/sources of thesweetpotato germplasm in Plant Genetic Resources Centre,Universiti Putra Malaysia

Country/Source Number of AccessionsMalaysia 132Peninsular Malaysia 86

Sarawak 28Sabah 18

Indonesia 55Irian Jaya 30Java 25

South America (CIP) 16

AVRDC 14Philippines 20Total 217


During 1983–1996, a total of 99 accessions were collected from five areas in Sabahand Sarawak. In 1988, collecting was started in Peninsular Malaysia. To date, the totalnumber of accessions collected from Peninsular Malaysia is 151. The collection coversalmost all parts of Malaysia (Fig. 1).

Fig. 1 Map of Malaysia showing the sites of sweetpotato germplasm collection (black spots)

In 1988, a total of 20 sweetpotato accessions were obtained from AVRDC, Taiwan, andin 1994 CIP sent 20 mostly South American accessions. In 1997, collaborative work wasstarted with IPGRI to study genetic variation of sweetpotato from different subregionsin Asia using molecular markers (RAPD and SSR). Through this collaboration,sweetpotato germplasm have been obtained from Indonesia and Philippines. Thegermplasm from Philippines were obtained through Visayas State College of Agriculture(ViSCA).

Native cultivars and breeding lines

Table 2 presents the numbers of native cultivars and breeding lines within thesweetpotato germplasm collected from within Malaysia. They comprise mostly nativecultivars that are being grown by farmers. Of the132 accessions from Malaysia, 67 wereactually collected from farmers’ fields. Most farmers prefer to grow their own cultivars.The more advanced farmers select their own cultivars and share or sell the cuttingsto their friends and other farmers. Many farmers grow several cultivars on their farms.The choice of cultivars grown by farmers depends very much on the market demandat a particular time and areas. They normally grow cultivars that produce high yieldand those with special characters that capture higher price. Normally, the cultivars grownby farmers from different areas are not similar. However, in Peninsular Malaysia, afew of the very popular cultivars were found grown by several farmers in differentstates.

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Table 2. Numbers of native cultivars and breeding lines in PSGT sweetpotato germplasm fromMalaysia

Source Total Native Cultivars Breeding LinesPeninsular Malaysia 86 46 (53.5%) 13 (15.1%)Sarawak 28 13 (46.4%) 1 (3.6%)Sabah 18 8 (44.4%) 0 (0.0%)Total 132 67 (50.8%) 14 (10.6%)

In 1995, a polycross breeding programme using 20 selected local germplasm was started.Several potential breeding lines or clones have been isolated. To date, a total of 12potential clones have been put into the list of our sweetpotato germplasm. These cloneswere selected for high yield and hardiness. They are being subjected to further testingand evaluation. Only two released varieties were included in our germplasm collection,both released by MARDI, namely Bukit Naga and Gendut.

Method of conservation

All the sweetpotato germplasm were kept in a field genebank. For the purpose ofcharacterization and evaluation, they are planted in the field in rows and replicatedtrials. At the same time, they are also planted in culvert rings (Fig. 2). Sweetpotatocan be maintained in culvert rings for a period of two years without replanting. Inaddition, the area can be maintained easily, plants will not mix and they require lessspace (Saad 1995). In 1998, an in vitro laboratory was set up to produce virus-free plantingmaterials and conserve germplasm in vitro. Initial work has started and a total of 30accessions are now being tested for in vitro conservation.

Fig. 2 Planting sweetpotato germplasm in culverts. Spreading out vines aretrimmed and the surrounding areas can be easily kept clean.


Passport data, characterization and agronomic evaluation

All sweetpotato accessions collected from Malaysia have complete passport data andinformation on farmer knowledge is also available. However, those obtained from othersources are without complete passport data (Table 3). Characterization has been doneon 213 of the accessions. Four new accessions were collected recently from PeninsularMalaysia and they are now being planted in the field for characterization and evaluation.Agronomic evaluation was done using both single row and replicated trials. Nutritionalcharacters (dry matter, protein and carbohydrates) were measured using the NIRSmachines (Saad 1996; Saad and Yunus 1996). Generally the characteristics of theMalaysian sweetpotato are not much different from those from other countries (Saadet al. 1999a; 1999b). However, there is wide variation in leaf and yield characters,nutritional characters and plant types.

Table 3. Numbers of accessions with passport data, characterized and agronomically evaluatedNumber of Accessions

Country/ Source Total Passport Characterization Agronomicdata data evaluation data

Malaysia 132 132 128 128Indonesia 55 – 55 55South America (CIP) 16 – 16 16AVRDC 14 – 14 14Philippines 20 – – –Total 217 132 213 213

Molecular characterization

In 1997, PSGT and IPGRI started a collaborative effort to study sweetpotato geneticdiversity using RAPD and SSR molecular markers. DNA extraction has been completedon 147 accessions. They are from Indonesia (53), Malaysia (60), South America (14) andthe Philippines (20) (Table 4). The samples from the Philippines have just arrived andat the time of writing this report they were still in quarantine. PCR analysis has beendone on 84 of the samples.

Table 4. Countries of origin and numbers of sweetpotato accessions used in the RAPD analysis

Country Number of DNA PCR BandAccessions Extraction Analysis Analysis

Indonesia 53Irian Jaya 28 20 10Other Areas 25 20 –

Malaysia 60Sabah 8 5 4Sarawak 8 6 5Kedah 8 5 1Johor 6 – –Selangor 7 2 2Terengganu 7 1 1Kelantan 5 1 1Pahang 6 5 1Perak 5 5 1

South America 14 14 14 14 Total 127 127 84 40

13

As for the RAPD analysis, a total of 54 primers were tested and 19 of them were foundto show variation in banding pattern (Table 5). So far, RAPD analysis using 19 primershas been completed for the South American samples. Analysis of the Indonesian samplesis almost 85% completed. However, only 50% of the samples from Malaysia have sofar been analyzed.

Work on SSR is still in the preliminary stage. We are testing primers from varioussources that might work for the samples.

Table 5. List of primers used in the RAPDanalysis in sweetpotato

Primer No. Sequences (5’ – 3’)OPG 2 GGCACTGAGGOPG 3 GAGCCCTCCAOPG 4 AGCGTGTCTGOPG 5 CTGAGACGGAOPG 6 GTGCCTAACCOPG 8 TCACGTCCACOPG 9 CTGACGTCACOPG 13 CTCTCCGCCAOPG 14 GGATGAGACCOPA 5 AGGGGTCTTGOPA 8 GTGACGTAGGOPA 20 GTTGCGATCCOPB 3 CATCCCCCTGOPB 7 GGTGACGCAGOPB 11 GTAGACCCGTOPC 1 GGAGGGTGTTOPC 10 TTCGAGCCAGOPD 1 ACCGCGAAGGOPD 6 ACCTGAACGG

The use of RAPD markers for duplicate detection

Six sweetpotato accessions from Malaysia that were identified as duplicates, namely308-B, 309-B, 423-D, 428-D, 448-D and 451-C, were subjected to RAPD analysis. A totalof nine primers were used in the study. The results showed that four of the primers,namely OPG2, OPG3, OPG9 and OPG14, produced polymorphic bands. Thus resultsshowed that the accessions 308-B and 423-B were differentiated from the other accessionsby primer OPG3 while 308-B was differentiated from 423-B and the rest by primer OPG14.Accessions 451-C and 428-D were differentiated from the other six accessions by primerOPG2. The primer OPG8 differentiated accession 428-D from 451-C and the rest. It wasclearly shown that only accessions 309-B and 448-D were similar and confirmed asduplicates (Fig. 3).


Fig. 3 Dendogram from cluster analysis on six sweetpotato duplicates based on RAPD bandingpattern using 9 primers

3 3 4 4 4 40 0 4 5 2 28 9 8 1 8 3B B D C D B

1.6 + | _______________________________ | . _________________________ 1.4 + . _________________________

| . _________________________| . _________________________

1.2 + . _________________________| . _________________________

D | . _________________________i 1 + . _________________________s | . _________________________t | . ___________________ .a 0.8 + . ___________________ .n | . ___________________ .c | . ___________________ .e 0.6 + . ___________________ .

| . ___________________ .| . _____________ . .

0.4 + . _____________ . . | . _____________ . .

| . _____________ . .0.2 + . _______ . . .

| . _______ . . .| . _______ . . .

0 + . _______ . . .

15

ReferencesMOA. 2000. Keluasan Tanaman Pelbagai (Area of Miscellaneous Crops). Kementerian

Pertanian Malaysia, Kuala Lumpur, Malaysia.Saad, M.S. 1995. Planting sweetpotato germplasm in culverts. SAPPRAD Newsletter

9 (1):14.Saad, M.S. 1996. Genetics and variabilities of starch, protein, fibre and ash in

sweetpotatoes from Malaysia. Selected Research Papers 94/95 (Vol. 2 –Sweetpotato):203-210.

Saad, M.S., M.S. Ramisah, A.G. Yunus, E. Nissila and M.S. Nordin. 1999a. Applicationof RAPD markers in duplicate detection in sweetpotato germplasm. Presented ata Symposium on Genetic Resources of Borneo, Kota Kinabalu, Sabah, Malaysia,26–28 October 1999.

Saad, M.S., T.C. Yap, A.G. Yunus, M.A. Kadir and M.S. Nordin. 1999b. Genetic diversitywithin and between locally adapted sweetpotato germplasm from different sub-regions of Sarawak and Sabah, Malaysia. Presented at a Symposium on GeneticResources of Borneo, Kota Kinabalu, Sabah, Malaysia, 26–28 October 1999.

Saad, M.S. and A.G. Yunus. 1996. The determination of starch in sweetpotato roots usingnear infrared (NIRS) reflectance spectroscopy. Presented at the 1st Asian Sweetpotatoand Potato Research and Development Meeting, Malang, Indonesia, August 27–30, 1996.


In Vitro Conservation of Sweetpotato Germplasm

Guo Xiaoding1, Zhou Ming-De2 and Wang Yi3

1 Xuzhou Sweetpotato Research Centre, Xuzhou, Jiangsu Province 221121, China;2 Eastern Asia Office, International Plant Genetic Resources Institute, Beijing 100081;3 Liaison Office in Beijing, International Potato Centre, Beijing 100081, China

Introduction

Sweetpotato is a vegetatively propagated crop with high yield and nutritional value.Sweetpotato is highly efficient in converting light energy into organic matter. Generally,the roots are used, but the leaves are also edible and widely consumed in New Guineaand East and Southern Africa. As new uses of sweetpotato are continuously beingdeveloped, as medicine, as a source of natural pigments, etc., it is obviously veryimportant to carry out research on its germplasm. Hence there is the increased focuson collecting and conservation of sweetpotato germplasm.

Evaluation of conservation system of sweetpotato germplasm

Sweetpotato is propagated by using roots, shoot tops and stem segments. In thetemperate region, the principal reproductive organ is the root, which contains a highpercentage of water, approximately 65–85%. Because of their bulkiness, sweetpotatostorage roots are difficult to store and transport. Owing to its hexaploid nature andhybrid origin, sweetpotato offspring segregates, and the unique genetic constitutionof the parents is lost in the progeny. The plant is an out-breeder and homozygous lociare therefore rare. Sweetpotato genotypes fall into different cross sterility groups. Crossesbetween genotypes of a given group result in no or very low fruit and seed set.

Clonal sweetpotato germplasm is currently conserved in field and in vitro genebanksso as to make it available for exchange, evaluation and use in the long term.

Field genebank: In the temperate region sweetpotato is regarded as an annual crop becauseof the seasonally determined cycle of bedding (for the production of propagules),transplanting, harvesting and storage. However, in the tropics sweetpotato is regarded asa perennial. In this case, the germplasm is continuously replanted for several years. Thusa field genebank can be sustained in one site for a long term. Field maintenance offers severaladvantages over in vitro conservation such as ease of operation, and no need for specializedstaff, costly equipment and sophisticated techniques. Field maintenance allows the agronomicevaluation of germplasm for use in breeding and varietal improvement (Huang and Chen1991). But this system has the following drawbacks as compared with in vitro maintenance:1) Extensive land is needed (a problem in China and other densely populated countries).

For example, in Xuzhou, China, 12 plants are maintained per accession. They occupya plot of 2.55x2.25 m. Thus, 1000 accessions require approximately 0.6 ha;

2) Labour costs. Field maintenance involves bedding, transplanting, harvesting andstoring, which must be repeated every year;

3) Disease build-up especially of virus, and subsequent decline of plant vigour,frequently resulting in loss of the materials;

4) Poor ecological adaptation of certain accessions to the maintenance site often resultsin loss of material due to drought, water logging (rotting) or inappropriate storageconditions. Poor adaptation to edaphic or climatic conditions may also lead to plantsnot forming storage roots;

5) Theft of genetic material;

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6) Bulkiness of propagating material for transport;7) Quarantine restrictions of field-grown sweetpotato, especially for the international

movement of germplasm.

In vitro genebank: There are three methods for conserving sweetpotato germplasmthrough in vitro maintenance: 1) as test tube plantlets, which is the most common form;2) as artificial seed, developed in recent years; and 3) cryopreservation for long termstorage. All these methods precede by tissue culture. In the following, we will analyzeand compare these methods.

Unlike field maintenance, in vitro conservation can be carried out withoutconsideration of climatic and edaphic factors, resulting in a high propagation coefficient.Under the sterile conditions of in vitro culture, the plantlets can be maintained freefrom diseases, viruses and pests. Owing to labour and space saving, more germplasmcan be conserved. Tissue culture also allows the conservation of special material, suchas outbreeding offspring and the plants produced by somatic hybridization (Xia andZhu 1987), or materials bearing resistant genes but not producing storage root. In vitromaterials occupy less volume and are more convenient for transportation than fieldgrown propagules. There is less restriction in quarantine when the materials areexchanged internationally (Engelmann 1991).

However, in vitro maintenance has disadvantages. In vitro plantlets cannot becharacterized and evaluated like field-grown plants. Tissue culture requires electricalenergy for the refrigeration of culture rooms and the operation of critical equipment.This is not only expensive but also makes in vitro culture vulnerable to power cuts,which can be common in developing countries. Requirements of hygiene in tissue cultureare very strict; otherwise contamination by microbes will lead to loss of the materials.Moreover, tissue-cultured material is prone to the occurrence of somatic variation, whichremains hidden, whereas most asexual variants can be eliminated in field-grown materialwhere they manifest themselves as changes in colour or shape (Engelmann 1991). Indeveloping countries, the prices of some consumables, such as electric power, chemicalreagents, etc., are relatively high, so the cost of in vitro conservation is more expensivethan that in field genebank.

Cryopreservation of plant germplasm has been explored in recent years for itspotential for long-term conservation. Some success in cryopreservation of potato andcassava has been achieved. Thus, short- to middle- and long-term in vitro conservationcomplement each other to make a combination of conservation and application ofsweetpotato germplasm (Fig. 1). In Fig. 1, base collection is conserved under long-termconditions, which, without considering application, emphasizes on gaining the highestsafety factor in order to avoid loss of the materials, while active collection is used forgermplasm evaluation and distribution, and gives more attention to application.

Botanical seeds: In the first ANSWER meeting held in 1996, the possibility of conservinggermplasm by applying botanical seeds was discussed. Sweetpotato has orthodoxbotanical seed, meaning they withstand desiccation and can be stored at lowtemperatures (refrigerated or frozen) for decades without significant loss ofgerminability. As an outbreeder and owing to its hexaploid and heterozygous nature,sweetpotato seed progenies release much variation and thus cannot be maintained trueto type. Therefore, storage of seeds is not used for sweetpotato germplasm conservationin China (Guo et al. 1996). However, if the conservation of genes as opposed to themaintenance of genotypes is considered in the future, the botanical seeds spontaneouslyproduced or obtained through artificial hybridization could be a suitable method forlong-term conservation.


Fig. 1 In vitro conservation, exchange and utilization of sweetpotato germplasm

Methods of in vitro conservation

Test-tube plantlets: By combining suitable physical and chemical factors slow growthor minimal growth can be induced during tissue culture in order to facilitate extensionof length of conservation. These factors are described as follows:1) Temperature of culture room. The most suitable temperature for sweetpotato tissue

culture is 26–28°C. At 18–20°C, its growth is retarded. Jarret and Florkowski (1991)reported that when culture temperature was reduced from 21.1 to 15.6°C, growthof the in vitro plantlets was reduced to 50%. Temperature reduction is the usualmethod to slow down plantlet growth thus extending the time between regenerations(Xin 1985; Lin and Li 1989; Huang and Chen 1991; Bertrand-Desbrunais et al. 1992;Van den Houwe et al. 1995; Angel et al. 1996).

2) Illumination. Normally test-tube plantlets are grown under 14–16 hr photoperiodconditions with light intensity of 3000–4000 lx. When the photoperiod is reducedto 8–10 hr and light intensity to 1000 lx (Xia and Zhu 1987; Xin 1987; Song et al.1991), rate of photosynthesis is reduced and growth will be retarded. Jarret (1991)observed that, when the photoperiod was reduced from 16 to 4 hr, the plantletscould grow normally even though they showed some chlorosis. To date there isno report concerning the influence of light quality on storage of sweetpotato test-tube plantlets.

3) Atmosphere. Reducing pressure of oxygen partially slows down the metabolism ofcells and favours plantlets storage (Xia et al. 1989), but it needs more complex facilityand equipment, thus it is not practical.

International germplasm exchange

Micropropagation

In vitro genebank

Active CollectionSlow growth conservation

Artificial seeds plantlets

Base CollectionShoot tip cryogenic storage

National Programme Germplasm Conservation Center

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Experiments have also shown that it is also possible to inhibit the growth of test-tubeplantlets with addition of special chemicals to the conservation medium:1) Phytohormone: Higher concentrations of ABA (abscissic acid) and KT (kinetin) can inhibit

the growth of tube-cultured plant. For example, 1–10 mg/l ABA can completely inhibitthe growth of the axillary bud, but when the plant hormone is removed from the growthmedium the plant begins to grow normally (Xin 1987; Xin 1989a; Jarret and Florkowski1991). The survival ratio of the tissue-cultured sweetpotato after one-year conservationreaches 71.3%, if 10 mg/l KT is added to the MS culture medium (Xin 1989a; 1989b). Beyonda certain concentration of ABA, however, the survival ratio declines (Lin and Li 1989).

2) Growth inhibitor: If used at proper concentrations, the inhibitor can retard thegrowth of the tube-cultured plants, as shown in potato and taro (Lin and Li 1989;Song et al. 1991). Glyphosate (1 mg/l), CCC (cycocel, 100–500 mg/l) (Xin 1989a),methyl succinic acid (50–70 mg/l) (Zhou 1987) and paclobutrazol (PP333, 3–5 mg/l) (unpublished data) served to inhibit the growth of tube-cultured sweetpotato.Some other known inhibitors are B9 (dimethyamuno succinamic acid, 10–30 mg/l) (Zhou 1987) and MH (maleic hydrazide, 10 mg/l) (Xia and Zhu 1987).

3) Hyperosmolar material: Addition of some hyperosmolar material such as sucrose,mannitol and sorbitol, etc., can lower the rate of water and nutrient absorption by theplantlets from the medium resulting in retarded growth of the culture. Among thesematerials, mannitol is widely used in the germplasm conservation using tissue culturemethods (Huang and Chen 1991; Song et al. 1991). The appropriate mannitol concentrationin sweetpotato is 1–1.5% (Xin 1989a; Jarret 1991;) and plants will be injured at higherconcentration (Huang and Chen 1991). Other experiments demonstrate that a high pHvalue accompanies the mannitol after autoclave sterilization (Liang 1987).

4) Carbon resource: The decrease of the sucrose concentration in the culture mediumfrom 30 to 15–20 g/l can induce slow growth (Jarret 1991). Both higher and lowersucrose concentrations can weaken the tissue culture growth, resulting in retardedbiomass accumulation (Lo and Liao 1993). Sucrose acts as the carbon resource andbalances osmotic pressure. Different carbon resources have different effects. Forexample, if 3% glucose replaces sucrose, the culture shows weak growth. If lactose,maltose, mannose, galactose or arabinose is used as the carbon source, the culturewill fail to grow after some time (Lo and Liao 1993).

Artificial seed: The recently developed technique of artificial seed was intended foragricultural production purpose. Tang et al. (1994) demonstrated the utility of axillary budas artificial seed of sweetpotato. Nowadays, artificial seed is considered as a method ofgermplasm conservation (Guo et al. 1997). The production of artificial seed involves thefollowing steps: stem segments with axillary buds (about 3 mm long) of plantlets in vitroare encapsulated by 4–5% sodium alginate in MS culture medium, packing the resultingbeads in petri dish or test tube for storage. The artificial seed can be transplanted fromtissue culture onto horticultural substrates thus ensuring good genetic stability.

Using artificial seed has the following advantages:1) Saving space for conservation. A petri dish or a test tube can contain 50 pieces of

artificial seed and thus replace 15 conventional culture tubes that are usuallynecessary for one accession.

2) Extending the intervals between reculturing. After transplanting onto the culturemedium, the artificial seed germinate in approximately a month; when kept in astorage room (18–20°C) the germination can be retarded for about two months.

3) Artificial seed show stronger regeneration ability. They can continue to grow inthe culture medium into young plants, or they can directly be grown on horticulturalsubstrate. When planted in sand, in vermiculite and in perlite, artificial seedgerminated normally (unpublished data).


Cryopreservation

The advantages of cryopreservation include minimum space requirements for germplasmstorage, no need for reculturing and low incidence of somaclonal variation. This methodmakes conservation of genetic resources very simple and thus can promote betterconservation efforts. Conserving apical tips of potato and cassava by cryopreservation yieldedpromising results. The differences in viability of material conserved in liquid nitrogen forbetween 3 months and 4 years are not significant (Bajaj 1985). Cryopreservation was alsoemployed for sweetpotato to assess the viability of the material from shoot tip andembryogenic tissue (Towill and Jarret 1992; Blakesley et al. 1997). Although thecryoconservation of embryogenic tissue presents fewer problems than dealing with shoottip, the genetic stability shown by shoot tip is better than by the former. Towill and Jarret(1992) reported the first successful case of conserving the sweetpotato shoot tips from plantletsin vitro in liquid nitrogen through vitrification. The highest viability of the cryopreservedshoot tips from two sweetpotato clones was 83%. Vitrification presents no technical problems,since no programmed cooling machine is needed. The components of vitrification solutionwere 30% glycerol+15% ethanediol+15% dimethyl sulfoxide (DMSO). After storage in liquidnitrogen, part of the shoot tips treated by vitrified solution produced plantlets in the recoverymedium (Towill and Jarret 1992). Further research is needed to make cryopreservation aroutine method for the long-term conservation of sweetpotato genetic resources.

The genetic stability of in vitro conservation

Genetic stability evaluation of the material conserved in vitro: There should not bedifferences in phenotype between the materials maintained in the field and the onesregenerated from in vitro conservation. So it is very important to do morphologicalcharacterization. Based on the investigation, some biochemical analysis should beemployed to detect if variation has occurred in in vitro material, as evidenced by changesin its soluble protein or isoenzyme patterns (Dodds 1988). DNA-based techniques suchas RAPDs, developed in recent years, have improved the detectability of genetic changesat the molecular level.

Age limit of conservation: According to our research (unpublished), after 8–10 yearsconservation of sweetpotato plantlets in vitro in a medium containing 1% mannitol,no genetic changes occurred judging from isoenzyme and RAPD patterns. However,it is not sure whether the genetic changes occurring are directly related to the lengthof time they are conserved. There also seemed to be differences in rates of genetic changeamong different genotypes conserved in vitro which need to be studied. It is suggestedthat in vitro conservation and field maintenance should be undertaken in acomplementary mode, which will guarantee the safety of the conserved germplasm.

Research has shown that the ratio of genetic variation of somatic tissue from a vegetativelypropagated crop conserved in vitro is relatively high. In the presence of external stimuli,the variation tends to appear more frequently. Chromosomal variation can also be inducedby tissue culture (Shang 1984). Table 1 shows that high concentration of chemicals in culturemedium can induce variation (Xin 1989b). Morphological changes induced by mannitolare reversed under field conditions, but they are not with media containing growth inhibitorslike KT and CCC (Wang et al. 1989). Using DNA probes to evaluate genetic stability of potatoplants after in vitro maintenance showed that there were no RFLP alterations in cryopreservedplants, but there were alterations in plants regenerated from slow-growth media (usingmannitol) (Harding 1991). Using DNA markers it has been shown that plantlets producedthrough shoot tip or meristem culture are more genetically stable than those producedthrough a method that has a callus phase in it, as somatic variation is less in the former(Muller et al. 1990; Potter 1991).

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Table 1. The effects of three chemicals and their concentrations on the growth and stem colourof in vitro plants of sweetpotato variety Yiwohong (Xin 1989b)

Treatment Concentration (mg l-1) Yield per plant (g) Stem colour

Kinetin 5 420 purple10 450 green

Mannitol 15000 410 purple30000 100 green

ABA 0.5 230 purple1.0 175 purple

10.0 75 greenCK 0 389 purple

Conclusion

Currently, in vitro conservation of sweetpotato germplasm takes the form ofmicropropagated plantlets in test tubes from shoot tips. The system of artificial seedshould be improved to provide an alternative to conventional tissue culture.Cryopreservation of sweetpotato can be achieved through encapsulation anddehydration, which will avoid the variation caused by injury through vitrificationsolution. Sweetpotato tissue culture protocols can also be improved by adding mannitoland reducing sucrose or glucose in slow growth conserving medium, by the use of nodalsegment for propagation, conserving the material under conditions of 18–20°C, 8–10 hrphotoperiod, 1000–2000 lx luminous intensity. The genetic stability should be evaluatedby a combination of morphological characterization and molecular assessment.

ReferencesAngel, F., V.E. Barney, J. Tohme and W.M. Roca. 1996. Stability of cassava plant at the

DNA level after retrieval from 10 years of in vitro storage. Euphytica 90:307-313.Bajaj, Y.P.S. 1985, Cryopreservation of germplasm of potato (Solanum tuberosum L.) and

cassava (Manihot esculenta Crantz): viability of excised meristems cryopreservedup to four years. Indian Journal of Experimental Biology 23:285-287.

Bertrand-Desbrunais, A., M. Noirot and A. Charrier. 1992. Slow growth in in vitroconservation of coffee (Coffea spp.). 2. Influences of reduced concentrations of sucroseand low temperature. Plant Cell, Tissue and Organ Culture 31:105-111.

Blakesley, D., T. Percival, M.H. Bhatti and G.G. Henshaw. 1997. A simplified protocolfor cryopreservation of embryogenic tissue of sweetpotato (Ipomoea batatas [L.] Lam.)utilizing sucrose preculture only. Cryo-Letters 18:77-80.

Dodds, J.H. 1988, Review of in vitro propagation and maintenance of sweetpotatogermplasm. Pp. 185–192 in Exploration, Maintenance and Utilization of SweetpotatoGenetic Resources. CIP, Peru.

Engelmann, F. 1991. In vitro conservation of tropical plant germplasm – a review.Euphytica 57: 227-243.

Guo, X.D., D.F. Ma, H.M. Li and J. Tang.1997. Sweetpotato breeding and artificial seedsconservation in China. Pp. 119–130 in Proceedings of MAFF-PRCRTC InternationalWorkshop (L. Rolinada and Talatala-Sanico, eds.). MAFF, Tsukuba.

Guo, X.D., B.F. Song and M.D. Zhou. 1996. Status of sweetpotato germplasm researchin China. Pp. 70–76 in Proceedings of the Workshop on the Formation of A Networkfor the Conservation of Sweetpotato Biodiversity in Asia (V. Ramanatha Rao, ed.).IBPGR, Singapore.

Harding, K. 1991. Molecular stability of the ribosomal RNA genes in Solanum tuberosumplants recovered from slow growth and cryopreservation. Euphytica 55:141-146.

Huang, J.H. and Sh.R. Chen. 1991. In vitro storage of ginger germplasm. Journal ofSouthwest Agricultural University 13(3):310-312 (in Chinese with English summary).


Jarret, R.L. 1991. Chemical and environmental growth regulation of sweetpotato (Ipomoeabatatas [ L.] Lam.) in vitro. Plant Cell, Tissue and Organ Culture 25:153-159.

Jarret, R.L. and W.J. Florkowski. 1991. Abscisic acid-induced growth inhibition ofsweetpotato (Ipomoea batatas L.) in vitro. Plant Cell, Tissue and Organ Culture 24:13-18.

Liang, H.M. 1987. Points for attention of using mannitol as osmotic addition in planttissue culture. External Crop Tissue Culture 21:123-124 (in Chinese).

Lin, Ch.Ch. and Q.W. Li. 1989. Elimination of potato viruses and preservation of thepotato germplasm by the method of tissue culture. Journal of Potato 3(2):73-78 (inChinese with English summary).

Lo, S.F. and C.H. Liao. 1993. Studies on the in vitro maintenance techniques ofsweetpotato (Ipomoea batatas L.) I. Influence of carbon sources. Journal of AgriculturalResearch, China 42(1):30-36 (in Chinese with English summary).

Muller, E., P.T.H. Brown, S. Hartke and H. Loez. 1990. DNA variation in tissue-derivedrice plants. Theoretical and Applied Genetics 80:673-679.

Potter, R. 1991. An assessment of genetic stability of potato in vitro by molecular andphenotypic analysis. Plant Science 76:239-248.

Shang, X. M. 1984. The chromosome variation in plant tissue culture. Journal ofCytobiology 6(1):5-12 (in Chinese).

Song, M., X.J. Wang and Sh.R. Chen. 1991. In vitro preservation and propagation oftaro. Journal of Southwest Agricultural University 13(4):409-412 (in Chinese withEnglish summary).

Tang, Sh.H., M. Sun, K.P. Li and Q.T. Zhang. 1994. Studies on artificial seed of Ipomoeabatatas L. Lam. Acta Agronomica Sinica 20(6):746-750 (in Chinese with Englishsummary).

Towill, L. E. and R.L. Jarret. 1992. Cryopreservation of sweetpotato (Ipomoea batatas [L.]Lam.) shoot tips by vitrification. Plant Cell Reports 11:175-178.

Van den Houwe, I., K.D. Smet, H.T. Momtcel and R. Swennen. 1995. Variability in storagepotential of banana shoot cultures under medium term storage conditions. PlantCell, Tissue and Organ Culture 42:269-274.

Wang, Y.H., J. Tang, X.D. Guo and J.Y. Wu. 1989. Preliminary study on genetic stabilityof sweetpotato (Ipomoea batatas L.) maintained in vitro. Pp. 204-209 in A Treatiseon Storage of Crop Germplasm Resources (Y. Sh. Ma, ed.) (in Chinese with Englishsummary).

Xia, X.Zh. and F.M. Zhu. 1987. Studies on storage medium for tube seedling of potato.Acta Agriculturae Boreali-Sinica 12(1):37-42 (in Chinese with English summary).

Xin, Sh.Y. 1985. Preservation of sweetpotato germplasm by tissue culture. Crop GeneticResources 3:24-26 (in Chinese).

Xin, Sh.Y. 1987. Studies on meristem culture and in vitro preservation of sweetpotato.Crop Genetic Resources 4:34-36 (in Chinese).

Xin, Sh.Y. 1989a. Technology and condition for germplasm for germplasm preservationof sweetpotato (Ipomoea batatas Lam.). Pp. 2–9 in A Treatise on Storage of CropGermplasm Resources (Y. Sh. Ma, ed.) (in Chinese with English summary).

Xin, Sh.Y. 1989b. Effects of chemical on the preservation of sweetpotato germplasm.Pp. 10–15 in A Treatise on Storage of Crop Germplasm Resources (Y. Sh. Ma, ed.)(in Chinese with English summary).

Zhou, M.D. 1987. The effects of methyl succinic acid on growth and preservation ofplantlets of sweetpotato in vitro. Crop Genetic Resources 4:27-28 (in Chinese).

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Fig. 1 The artificial seeds of 8 sweetpotato varieties were conserved at 18–20°C for 4 months

Fig. 2 Harvest of sweetpotato germplasm in late October in Xuzhou sweetpotatofield genebank


Fig. 3 Plant grown on perlite culture medium for 4 months grown from artificialseeds of cultivar Xushu 18 conserved for 5 months

Fig. 4 Plantlets grown from artificial seeds of 4 sweetpotato cultivars afterinoculating on MS medium supplemented with 1% mannitol (130 days)

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Present Status of Sweetpotato Germplasm Conservation inIndonesia

M. Jusuf1, St.A.Rahayuningsih1 and Minantiyorini2

1Research Institute for Legume and Tuber Crops, Malang, Indonesia;2Research Institute for Food Crops Biotechnology, Bogor, Indonesia

Introduction

Indonesia, Papua New Guinea and the South Pacific islands are generally regardedas the secondary centre of genetic diversity. In Indonesia, sweetpotato is cultivated invarious agroecological zones ranging from the humid tropics to subalpine regions over3000 masl.

In general, most sweetpotato farmers in Indonesia still use hundreds of local cultivarsplanted in different environments. Farmers have for a long time used these local cultivarswhich are well adapted to different soil and climatic conditions. Naturally, local cloneshave developed resistance to environmental stresses and major pests and diseases.Therefore, they constitute very valuable genetic resources for the breeders.

The cultivars used by the farmers in Indonesia are different from one region toanother. In Java, the farmers grow one or two of the most popular cultivars in largeareas with, to a lesser extent, several additional but less popular ones. This practiceapparently may cause genetic erosion and endanger future breeding efforts (Manwanand Dimyati 1989). In contrast, in Irian Jaya the farmers usually grow a large numberof cultivars in a particular field. However, they prefer early-maturing varieties, whichcan lead to the loss of late-maturing cultivars. This is supported by recent findingsof late-maturing cultivars becoming rare (La Achmadi 1988).

So far, over 1155 accessions have been conserved at CRIFC (RILET and RIFCB).Among these, 427 local cultivars of Irian Jaya were received from CIP-ESEAP, Bogor,and are being conserved in these two institutes. Accessions conserved include releasedvarieties, elite breeding lines, local cultivars and introductions.

Up to now, sweetpotato germplasm is maintained in the field using stem cuttingsand sprouts for propagation and in tissue culture. Accessions maintained in the fieldgenebank are harvested 4–5 months after planting thus allowing two re-plantings peryear. About 200 accessions are conserved in in vitro culture and cryopreservation isbeing studied.

Germplasm conservation and management

Current status of sweetpotato germplasm conservation

Sweetpotato germplasm conservation is a complex activity and includes both clonalmaintenance and seed conservation. Agencies involved in the germplasm conservation,evaluation and utilization in Indonesia include the two research institutes under theCentral Research Institute for Food Crop (CRIFC), namely the Research Institute forLegume and Tuber Crops (RILET) and the Research Institute for Food CropsBiotechnology (RIFCB), Cendrawasih University in Irian Jaya as well as CIP-ESEAPRegional Office in Bogor.

Considerable progress has already been made in terms of numbers of accessionsof sweetpotato genetic resources maintained at CRIFC. To date, over 1155 accessionshave been conserved at two research institutes: RIFCB in Bogor and RILET in Malang.


Compared to 3 years ago (623 accessions), the number has increased considerablybecause more accessions have been received from CIP-ESEAP, Bogor, especially IrianJaya collection and also exploration carried out by RIFCB and RILET. Accessions includereleased varieties, elite breeding lines, local cultivars, and introductions (Table 1).

Table 1. Numbers of sweetpotato accessions conserved in Indonesia in 1996 and 1999*Source: Jusuf et al. 1996.

Sources of collection1996* 1999

Number Percentage (%) Number Percentage (%)1. Improved varieties 3 0.5 8 12. Native cultivars 501 80 916 793. Introductions 17 3 32 34. Breeding lines 102 16 199 17Total 623 100 1155 100

Aside from CRIFC, CIP-ESEAP and Cendrawasih University (in Manokwari Irian Jaya)also maintain sweetpotato collections, especially in situ collection of Irian Jayagermplasm. To minimize duplication, national coordination is needed to enableinstitutions and scientists involved in sweetpotato germplasm conservation to becomemore efficient and effective in defining and accomplishing relevant and significant work.

From Table 1, it can be seen that that most of the collections come from native cultivarswith 916 accessions (79%) followed by elite breeding lines (199; 17%). Of the nativecultivars, about 426 accessions (47%) are Irian Jaya germplasm donated by CIP-ESEAPregion in 1998. All the information on Irian Jaya germplasm has been computerizedby CIP-ESEAP and a database is maintained in Bogor. In addition to Irian Jayagermplasm, collection from Java contributes 253 accessions (28%) followed byNusatenggara (83; 9%) and Maluku (40; 4%) (Table 2). The following quality charactershave been determined for 101 accessions: fibre, sugar, starch, and total soluble solidand water contents. The results of this analysis are given in Appendix 1.

Table 2. Numbers of native sweetpotato cultivars in Indonesia (by Island of origin) conservedin the field*Source: Jusuf et al. 1996.

Island of origin 1996 1999Number Percentage (%) Number Percentage (%)

1. Sumatera 241 48 56 62. Java 167 33 253 283. Bali 46 9 46 54. Nusa Tenggara 33 7 83 95. Kalimantan 0 0 5 16. Sulawesi 14 3 40 47. Maluku 0 0 7 18. Irian Jaya 0 0 426 47Total 501 100 916 101

Field genebank conservation

At CRIFC, the field genebank is utilized for ex situ conservation (maintenance) whileCendrawasih University and CIP-ESEAP practise both in situ and ex situ conservationmethods.

For a vegetatively propagated crop like sweetpotato, ex situ conservation strategyin field genebank is by far the most practical way. These ex situ collections need tobe fully characterized, evaluated, and information documented in a form that can be

27

easily accessed nationally and internationally. RILET and RIFCB are the two researchinstitutes that maintain sweetpotato germplasm under field genebank conservation.It is planted twice a year with cuttings obtained directly from the old field or fromsprouts derived from roots. Plot size for each accession is 1.0 m x 2.5 m with ten cuttingsper row. Sweetpotato conservation activities are very complex, tedious and require muchlabour. Every year, all germplasm accessions are raised in a nursery to get plantingmaterials and a large field is utilized for producing the new roots of each accession.It is re-established once a year with sprouts obtained directly from the regenerated row.

Complementary conservation technology

Due to maintenance problems of field genebanks, alternative conservation methodsare needed such as in vitro maintenance, on-farm conservation (in situ) or as botanicalseed conservation and cryopreservation.

In vitro conservation

Field genebanks are labour intensive and require much field space. To back up fieldcollections of important cultivars/accessions, in vitro maintenance is employed. Thisis to safeguard important collections being lost due to biotic and abiotic stresses. Anin vitro genebank has, therefore, been initiated to eliminate some of these problems.The genebank also acts as a duplicate collection of germplasm maintained in the field.

Maintenance in vitro has its advantages vis-à-vis field genebank, to avoid loss ofmaterial due to natural calamities, as well as diseases. However, a major problem withthis is genetic instability, as variations can easily occur during the in vitro maintenance,especially the somatic mutations as this is a clonal propagated crop. In vitro conservationis generally more secure, less expensive and labour intensive than seed root storage.It is also helps in exchanging healthy genetic resources as tissue cultured materials canbe made free of insects and diseases; thus in vitro conservation is an excellent technology.However, in vitro material cannot be evaluated and characterized as is possible withfield-grown material. At this moment as many as 200 accessions are conserved in vitroand they are subcultured once a year at RIFCB in Bogor.

In situ conservation

In situ conservation or on-farm conservation is now given emphasis because of therecognition of farmers as the source and keepers of many landraces. Farmer managedconservation would be complementary to an overall national crop germplasmconservation effort (Prain and Piniero 1996). In situ conservation is very effective wheregenetic diversity is high (Komaki 1998) such as in Irian Jaya and Nias Island in NorthSumatera (Jusuf et al. 1998). Therefore, this method seems to be adopted forcomplementary conservation strategy, and CIP-ESEAP and Cendrawasih University aremaintaining Irian Jaya collection in in situ form in Irian Jaya.

Botanical seed conservation

At the last meeting of ANSWER, it was agreed that the sweetpotato collection couldbe divided into three groups: 1. frequently used, 2. less frequently used, and 3. rarelyused. Group one consists of germplasm, which contains important traits and is frequentlyused by sweetpotato workers. The group with less frequently used germplasm containsinteresting or potentially useful traits, which may become more important in the nearfuture. The group with rarely used germplasm includes diverse accessions with noidentifiable use at present or accessions similar to but not identical to accessions in


the first and second groups. It was felt that groups 1 and 2 could be conserved in thefield and/or in vitro genebank while group 3 could be conserved as seeds (Rao andSchmiediche 1996). Botanical seed conservation can be complementary to clonalgermplasm conservation. Botanical seed storage effectively conserves genes containedin original accessions rather than specific genotypes or specific gene combinations (Raoand Schmiediche 1996). It is an inexpensive conservation method, but valuable traitsbecome apparent only after several years during evaluation of seed progenies (Komaki1998).

Botanical seeds of sweetpotato have never been used as a storage material inIndonesia. Although botanical seeds are easy to maintain and keep for the long term,they have so far been used only in breeding programmes. At this moment 20 671 seedsfrom 15 female parents are available (Appendix 2). These seeds come from polycrossnursery and open pollination.

Cryopreservation

Cryopreservation of cells and tissues is being examined as a promising approach. Theprinciple behind cryopreservation is to bring the cells into a non-dividing state bysubjecting the cultures to ultra-low temperature in liquid nitrogen (–196°C) in thepresence of cryo-protectants (Komaki et al. 1998; Yoshinaga 1998).

Cryoconservation appears to be the most secure method to conserve material fora very long period, but it is also the most expensive one. If somatic embryo orembryogenic callus is chosen for cryopreservation, then this method faces the problemof somaclonal variation that may occur during the process of tissue culture (Yoshinaga1998). At this moment research is undertaken at RIFCB (Research Institute for FoodCrop Biotechnology) to develop a protocol for cryopreservation of sweetpotato.

Problems with sweetpotato germplasm conservation: field genebank problems

Since sweetpotato is a vegetatively propagated crop, the major method of its conservationhas been to maintain field collections – a costly exercise in time, labour and space, unlikesexually propagated crops that can be conserved as seed. As far as conservation ofsweetpotato germplasm in field genebank is concerned, the following problems areencountered:1. High cost maintenance of large collection2. Risk of loss due to environment stresses3. Germplasm materials are not fully characterized; thus duplicates continue to be

maintained4. Lack of financial support5. Mix-up of identification labels.

Experience shows that several collections maintained in field genebanks were lost/missing due to drought, water logging and infestation of pests, including animals. Inorder to solve these recurring problems, it is suggested to conduct a study on theminimum number of accessions that needs to be maintained actively. This size shouldbe representative of the total genetic variability. Collection should be backed-up within vitro and botanical seed maintenance.

Documentation problems

RILET, RIFCB, CIP-ESEAP and Cendrawasih University have computerized all theinformation on Indonesia sweetpotato germplasm. RILET and RIFCB maintain thecentral database and share information on sweetpotato genetic resources, but sometimesthe institutions do not use common descriptors for characterization and management.

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Other problems include: lack of expert staff to do characterization and documentation;some characters are strongly influenced by environments; some accessions do notproduce roots, so that the root characters cannot be determined.

Exchange of germplasm problems

If germplasm is moved in the form of storage roots so are the diseases and insects presenton them. In vitro culture allows the elimination of bacterial, fungal and mycoplasmainfection. Within Indonesia, agencies working on sweetpotato freely exchangesweetpotato germplasm materials. With agencies outside the country, Indonesia hasto abide by the agreement of the Asian Network for Sweetpotato Genetic Resources(ANSWER) composed of 11 member countries, namely Indonesia, Malaysia, thePhilippines, Thailand, Vietnam, Sri Lanka, Japan, India, China, South Korea and PapuaNew Guinea. It was agreed that each member country could exchange genetic materialsin reciprocal manner with due recognition of the material received.

ReferencesJusuf, M., St. A. Rahayuningsih, Minantyorini, and I.G. Mok. 1998. Sweetpotato breeding

and genetic conservation in Indonesia. Pp. 49–62 in Sweetpotato Genetic ResourcesConservation and Use in Asia (R.L. Tatala-Sanico, ed.). Proceedings of MAFF-PRCETC International Workshop. Tsukuba, Japan.

Jusuf, M., Y. Widodo, St.A. Rahayuningsih and Suyamto. 1996. Sweetpotato geneticresources in Indonesia. Status and future outlook. Pp. 41–45 in Proceedings of theWorkshop on the Formation of a Network for the Conservation of SweetpotatoBiodiversity in Asia. CIP, Bogor, Indonesia, 30 April–5 May 1996 (V. RamanathaRao, ed.). IPGRI-APO, Serdang, Malaysia.

Komaki, K. 1998. Sweetpotato breeding and genetic resources conservation in Japan.Pp. 77–98 in Sweetpotato Genetic Resources Conservation and Use in Asia (R.L.Tatala-Sanico, ed.). Proceedings of MAFF-PRCETC International Workshop.

La Achmadi, 1988. Sweetpotato cultivar and cultivation system in Baliem valley,Jayawijaya Indonesia. Pp.103–142 in Proceedings of the Seminar on Rootcrops inIrian Jaya. July 27–29, 1988. Manokwari, Irian Jaya.

Manwan, I. and Dimyati. 1989. Sweetpotato production, utilization and research inIndonesia. Pp. 43–51 in Improvement of Sweetpotato (Ipomoea batatas) in Asia (CIP,ed.). Report of the Workshop on Sweetpotato Improvement in Asia, ICAR,Trivendrum, India. Oct. 24–28, 1988.

Prain, G. and M. Piniero. 1996. Communities as curators of plant genetic resources.The case of rootcrop conservation in Southern Philippines, IDRC-UPWARD FundedProject.

Ramanatha Rao, V. and P. Schmiediche. 1996. Conceptual basis for proposed approachto conserve sweetpotato biodiversity. Pp. 8–15 in Proceedings of the Workshop onthe Formation of a Network for the Conservation of Sweetpotato Biodiversity inAsia. CIP, Bogor, Indonesia, 30 April–5 May 1996 (V. Ramanatha Rao, ed.). IPGRI-APO, Serdang, Malaysia.

Yoshinaga, M. 1998. Cryopreservation of sweetpotato in Japan. Pp. 147–152 inSweetpotato Genetic Resources Conservation and Use in Asia (R.L. Tatala-Sanico,ed.). MAFF/PRCRTC, Philippines.


Appendix 1. Nutritional qualities of 101 germplasm accessions atRILET, 1995

Water Fibre Sugar Starch TotalNo. Acc number content content content content soluble

(% DB) (% DB) (% DB) (% DB) solid (%)1 MLG 12340 70.8 – – – 8.42 MLG 12501 69.7 3.6 3.0 45.3 9.03 MLG 12502 69.9 3.9 3.5 47.0 8.24 MLG 12503 70.9 3.8 3.4 45.7 8.05 MLG 12504 69.7 3.7 2.9 41.7 8.56 MLG 12505 71.5 3.2 2.2 45.9 6.77 MLG 12506 70.4 3.5 2.5 47.1 6.88 MLG 12507 74.1 – 0.8 45.1 7.69 MLG 12508 – 4.5 – – –10 MLG 12509 72.7 – 1.9 42.0 7.211 MLG 12510 74.8 5.1 17.5 29.6 7.712 MLG 12511 82.5 5.0 18.7 30.0 7.413 MLG 12512 66.8 2.4 1.8 60.0 8.814 MLG 12513 69.4 2.9 2.1 41.5 7.415 MLG 2515 – 2.9 2.1 46.7 –16 MLG 12516 – 3.8 1.4 47.6 –17 MLG 12517 68.3 2.8 2.3 40.9 8.018 MLG 12518 66.9 2.7 2.8 40.5 8.819 MLG 12519 67.2 2.9 2.7 46.9 8.520 MLG 12521 76.4 4.1 3.9 49.5 6.721 MLG 12522 66.8 3.0 2.1 40.3 8.522 MLG 12523 70.9 3.4 1.5 40.0 8.323 MLG 12524 69.8 – – – 8.224 MLG 12525 80.5 5.0 17.4 28.7 7.625 MLG 12526 66.3 3.0 3.3 59.7 10.426 MLG 12527 66.2 3.4 2.9 47.9 9.227 MLG 12528 70.6 3.4 2.3 46.6 8.928 MLG 12529 – 3.0 3.6 50.1 7.329 MLG 12530 64.1 2.8 1.7 43.1 9.930 MLG 12531 75.5 4.0 7.4 36.7 6.431 MLG 12532 73.5 3.4 2.5 46.8 7.432 MLG 12533 63.7 3.6 0.6 46.4 8.033 MLG 12534 79.2 4.0 4.2 45.4 8.034 MLG 12535 – 4.6 2.9 41.8 7.435 MLG 12536 76.9 4.0 3.6 47.3 8.136 MLG 12537 75.9 4.0 2.2 45.4 8.237 MLG 12538 77.9 – – – –38 MLG 12539 – 3.5 1.4 45.1 –39 MLG 12540 – 3.3 0.4 61.1 –40 MLG 12541 66.8 – – – 8.541 MLG 12544 70.9 – – – 7.542 MLG 12545 68.1 3.7 1.4 55.8 8.843 MLG 12546 69.7 3.6 1.1 44.7 8.744 MLG 12547 66.8 3.5 3.4 38.3 9.245 MLG 12548 68.7 3.5 2.0 39.2 7.246 MLG 12549 67.6 3.4 1.9 54.4 7.747 MLG 12550 70.5 2.9 2.5 48.2 8.848 MLG 12551 72.5 3.2 4.0 54.7 8.449 MLG 12553 73.8 – – – 7.450 MLG 12554 71.7 2.9 2.4 46.5 8.8

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Water Fibre Sugar Starch TotalNo. Acc number content content content content soluble

(% DB) (% DB) (% DB) (% DB) solid (%)51 MLG 12555 72.8 3.1 5.3 45.6 9.052 MLG 12556 67.8 3.1 1.7 47.4 7.653 MLG 12557 60.4 3.4 5.8 48.3 9.054 MLG 12558 70.2 3.2 3.1 52.2 8.655 MLG 12559 72.9 3.0 3.5 55.2 8.556 MLG 12560 – 3.8 1.0 47.8 –57 MLG 12561 74.1 3.5 5.4 45.9 7.758 MLG 12562 72.3 2.9 3.2 50.2 8.359 MLG 12563 70.4 3.6 4.2 46.6 8.760 MLG 12564 72.8 2.9 0.6 46.4 8.561 MLG 12565 71.3 2.9 3.2 58.3 7.362 MLG 12566 73.1 – – – 7.963 MLG 12567 73.7 – – – 7.864 MLG 12568 74.2 3.0 3.2 45.0 8.165 MLG 12569 73.9 3.2 3.0 47.1 8.066 MLG 12570 67.7 3.0 1.9 47.4 10.367 MLG 12571 73.8 3.3 3.1 44.9 7.268 MLG 12572 73.7 – – – 7.569 MLG 12573 69.2 2.8 2.0 55.0 7.870 MLG 12574 70.9 2.8 1.3 48.2 8.971 MLG 12575 71.3 3.9 6.0 46.4 10.472 MLG 12576 72.6 2.8 1.3 49.0 8.973 MLG 12577 73.2 4.9 1.8 40.8 8.074 MLG 12578 70.1 3.0 2.0 51.1 7.275 MLG 12579 79.2 4.1 3.1 37.3 8.576 MLG 12580 63.6 4.2 3.4 39.7 7.977 MLG 12581 78.1 4.7 2.3 43.6 8.778 MLG 12582 77.1 4.0 2.5 40.7 7.779 MLG 12584 73.3 3.4 1.6 52.8 7.880 MLG 12585 71.3 3.5 1.9 53.9 7.281 MLG 12586 71.8 3.4 4.2 55.2 7.182 MLG 12587 – 3.4 3.9 46.8 –83 MLG 12588 69.3 3.0 3.4 59.6 8.884 MLG 12589 71.1 3.1 2.7 53.7 7.585 MLG 12590 77.9 4.3 9.2 33.8 8.386 MLG 12591 69.4 2.5 1.0 56.4 6.787 MLG 12592 72.6 3.0 1.7 56.6 8.588 MLG 12593 71.3 2.9 1.1 56.5 7.989 MLG 12594 73.0 2.9 1.7 60.7 7.190 MLG 12595 72.1 3.1 1.8 51.1 8.691 MLG 12596 74.4 3.7 2.8 59.7 8.792 MLG 12598 74.4 2.8 3.9 59.6 6.993 MLG 12599 72.4 3.0 3.9 48.3 8.794 MLG 12600 77.9 3.7 3.8 55.6 8.695 MLG 12601 68.2 3.2 1.9 57.9 9.096 MLG 12602 – 4.0 1.9 42.6 9.797 MLG 12603 78.7 4.0 2.1 39.1 8.798 MLG 12619 62.2 – – – –99 MLG 12635 78.9 – – – 7.5100 MLG 12699 69.8 3.5 2.9 47.8 8.3101 MLG 12841 – 3.8 1.8 62.5 –

Note: ‘–’ data not available.


Appendix 2. Number of botanical seeds from sweetpotatogermplasm collection at CRIFC, 1999

Name of cultivars MLG # CIP #Number of

botanical seeds1. AB 94001-8 MLG 12830 – 202. B 0053-9 MLG 12833 – 9783. Binoras Op 95-2 MLG 12831 – 24274. Cangkuang MLG 12828 – 16755. Helalekeue baru MLG 12950 W 0006 3756. Helalekue MLG 12955 W 0220 B 4807. Hoboak MLG 12962 W 0279 4448. Inaswang Op 95-6 MLG 12832 – 21409. MIS 110-1 MLG 13274 – 172910. MLG 12588-1 MLG 12839 – 530211. Mikmak MLG 13066 W 0121 10012. Muara Takus MLG 12827 – 378313. Musan MLG 13083 W 0010 33014. Siate MLG 13149 W 0319 51315. Wortel MLG 13241 W 0017 375Total 20 671


Conservation and Documentation of Sweetpotato GeneticResources in Irian Jaya

Ery AtmojoThe Root and Tuber Crops Research Centre, Cendrawasih University, Jl. Gunung Salju,Manokwari, Irian Jaya, Indonesia

Introduction

In Irian Jaya, sweetpotato (Ipomoea batatas) plays an important role as the staple food.In highland areas, sweetpotato is used as the main staple food, while in lowland areasit is used mainly as a supplementary source of carbohydrate, or as a substitute for othermain staples like sago, taro or cassava, when the latter are not available. Besides, inmany parts of Irian Jaya, sweetpotato is also used as pig feed. In highland areas, theimportance of sweetpotato is indicated by the greatest dependence of people’ssubsistence on this crop (Schneider et al. 1993).

Although Central America is the place of origin, Irian Jaya is considered one ofthe centres of diversity for sweetpotato. In this province, farmers usually grow a largenumber of cultivars in any field (Jusuf et al. 1996). It is not known how many cultivarsexist in Irian Jaya, but Schneider et al. (1993) estimated that there are more than 1000cultivars grown in the western part of the highland. As a comparison, there were 2775accessions collected in Papua New Guinea (Guaf et al., 1996). Twenty percent of themwere identified as duplicates.

This paper will discuss briefly the recent progress on the conservation and the useof sweetpotato in Irian Jaya, especially during the last three years.


During the last three years, there was only one collecting trip, conducted in early 1999in Biak and Yapen islands in Northern Irian Jaya, which was conducted in collaborationbetween the Rootcrops and Sago Research Centre (RSRC) of the Cenderawasih University(Uncen), Manokwari, with the International Potato Centre (CIP) and Research Institutefor Legumes and Tuber Crops (RILET). Taro and other rootcrops were also collected.

A total of 55 sweetpotato accessions were collected from the lowland areas, 41 fromBiak, and 14 from Yapen. Passport data on all were also collected, but farmer (indigenous)knowledge on the accession could not be collected. In two collection sites, sweetpotatowas found to be less important than taro.

Samples collected from Biak and Yapen have been accessed into a genebank in Prafi,a transmigration area located 70 km from RSRC campus, or an hour by car, and havebeen characterized using IBPGR (now IPGRI) descriptors. The new accessions raise thetotal accession held by the RSRC up to 474 cultivars.

Field collections

The RSRC has its sweetpotato collection in two sites, one in Anggi (2100 m asl) andthe other in Prafi (100 m asl). At the present time, the Anggi site contains highlandaccessions from around Wamena, which were collected in 1993. The Anggi site collectionsare duplicates of collections maintained by CIP in Lembang, West Java. A total of 419accessions were transferred from Lembang and planted in Anggi in February 1999, andare in the process of being characterized. Prafi site contains lowland accessions fromBiak and Yapen. A total of 55 accessions were planted for the second planting season

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in June 1999. Characterization for the first planting season has been made anddocumented. About 15% were identified as duplicates and have not been eliminated.

In addition to 474 cultivars collected in Anggi site and Prafi site, around 100 cultivarsare maintained in Amban, at RSRC experimental station.

Conservation

Ex situ

The RSRC first collecting expedition was in late 1990 aimed at collecting sweetpotato,taro and cassava. Exploration sites were Tigi, East Paniai, and Kamu subdistricts ofPaniai District. Besides, a number of accessions were also collected from Northern Biaksubdistrict, Biak-Numfor district. A total of 149 sweetpotato accessions were collectedin the expedition (Matanubun et al. 1991). The samples are maintained in Amban, atRSRC experimental station. Another collecting expedition took place at Anggi in 1992(Sawor et al. 1993). In addition, individual researchers have given a number of accessionsthat they have collected in their own community service trips. In 1993, the size of thecollection had increased to 300 accessions from various parts of Irian Jaya.Characterization of 300 accessions was carried out during November 1992 to March1993 (Paiki 1993), and 204 accessions were characterized during August 1993 to January1994 (Yaku et al. 1994).

Owing to the long dry season, presence of sweetpotato little leaf (SPLL) disease(known as witches broom disease), and the lack of financial resources for the germplasmmaintenance, many accessions had died and the size of the collection had diminishedto around 100 accessions. To save the remaining sweetpotato cultivars from SPLLinfection, accessions obtained from highland areas were transferred to Anggi in 1994,and recent accessions from Biak and Yapen were maintained in Prafi instead of Amban.

Anggi site is located 45 minutes by plane, south from Manokwari. Plane trips areexpensive and very infrequent and make it difficult to monitor Anggi site. It is difficultto have someone to stay continuously to take care of the collection in Anggi due itsremote location.

In situ

The first in situ conservation site was established in central highland Wagawaga,Jayawijaya, in 1994. The sweetpotato conservation garden is cultivated and managedby the locals using farmers’ traditional practices. After a study of genetic diversity in1995, a follow-up documentation of a total of 30 beds of sweetpotato was carried outin 1998. The first study as well as the follow-up study counted 47 cultivars but only27 cultivars were the same cultivars the farmers planted in 1994 and in 1998 (Prain1999).

In early 1998, the conservation site was expanded. Wesaput, a village close to Waga-waga, and Kurima in the south of Wamena were chosen. In situ conservation studyin Wesaput involves a group of 24 women, and a group of 24 men. Documentationof the women’s garden is in process, while it was reported that 33 cultivars out of 47cultivars in the men’s garden have already been lost because of their characteristicssuch as late maturity, low yield, etc. (Prain 1999). A total of 67 Irian Jaya cultivars,together with 4 advanced clones were studied, and documentation is also in progress.

Because farmers were free to select cultivars they prefer and to eliminate cultivarsconsidered poor, genetic erosion seems to have taken place, and late maturity and lowyield cultivars could be lost.


In vitro

A study on in vitro conservation in RTSC was undertaken. A teaching staff of the Facultyof Agriculture has conducted this study aimed at identifying a suitable medium forin vitro growth of sweetpotato. Using fungicide and Bayclin (shirt whitening) for materialsterilization, and a combination of MS (Ubl) and coconut water as growth medium,a suitable composition of medium has been identified. There are now 22 accessionsmaintained in vitro. The research was financed by a grant from the Asian DevelopmentBank. Unavailability of fund has constrained the expansion of the research as well asthe expansion of sweetpotato in vitro conservation.

Utilization of sweetpotato genetic resources

Evaluation

Many studies to assess the agronomic performance of sweetpotato have been conductedby a number of RTSC’s staff and a number of students of the Faculty of Agricultureof Uncen in fulfilment of their undergraduate requirements. Unfortunately the researcheswere not made in an integrated manner. As a result, there were little research resultsthat could be combined to make a recommendation on conservation or further use ofsweetpotato genetic resources. In addition, comparison of research results thus obtainedis also difficult. Similar was the case with other studies, such as response to a particularpest or disease. The following are some conclusions of different studies, but these needfurther confirmation.

Forty-eight cultivars have been evaluated for their agronomic performance. Prafi-04 seems to produce a greater number of storage roots per plant, while seri and tigabulan seem to produce larger storage roots. Normally the experiments were conductedin Amban and/or in Prafi.

Research on sweetpotato resistance to SPLL disease has revealed that 60 out of 220cultivars studied were resistant to SPLL, while only 10 cultivars were highly susceptible.A total of 50 cultivars have been tested for their tolerance to aluminium toxicity and11 were found to be resistant, 9 not tolerant, and the remaining moderately tolerant.Ten out of 20 cultivars evaluated for resistance to scab were found to be highly resistant,and only 1 was highly susceptible. A total of 12 cultivars were involved in a numberof studies on sweetpotato resistance to Elsinoe batatas and 1 Irian Jaya cultivar (A-26)showed a high level of infection, while 5 cultivars showed very low infection. Twenty-four cultivars were tested for resistance to Cylas formicarius and none was found tobe resistant to the pest, though 4 cultivars were moderately resistant to the pest.

Only 7 cultivars have been tested for their beta carotene concentration in the storageroot. Among them, Mouwebsi seemed to have the highest beta carotene content of around5 mg/100 mg root flesh.

A study on scab intensity in Ransiki sub-district, and another study aimed atdetecting virus infection on sweetpotato are in progress.

Breeding

Efforts to breed improved sweetpotato has been limited so far. Research aimed atdetermining the cross compatibility of 4 Irian Jaya cultivars revealed that crosscompatibility was higher when semuel was used as female and tinta as male. It wasalso concluded that cultivar maria dan imobuna had the potential to be used as female,while tinta as male. However, botanical seed is not available for any clonal accessionin the RSRC.

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The RSRC has not produced breeding lines so far. However, there are several releasedvarieties held in Anggi and Amban sites, although the RSRC itself has not producedany released variety. Many accessions collected from Wamena have been spread toaround the Anggi and Amban sites. Farmers around the two sites, and Uncen workershave taken cuttings from germplasm to be cultivated in their gardens.

Documentation

Passport and characterization data of accessions in Prafi genebank have been storedinto a computer database. Similar data on accessions in Anggi site were also transferredto RSRC from CIP. Characterization database obtained from CIP also contains imagesof leaves and roots. A total of 1005 accessions have characterization data, and 527accessions have passport data (at least the name of the district where the accessionswere collected). Other 174 accessions can only be identified as highland accessions,and the remaining had no passport data. This is especially so with the accessions givenby individuals to the RSRC. Unfortunately, there are no accessions with farmer(indigenous) knowledge documented.

Though there have been many studies related to sweetpotato conducted in theFaculty of Agriculture of Uncen, results are dispersed in various units in the campus.It is difficult to pool all the research results. Besides, uncoordinated research makesit difficult to synthesize all the results. In turn, the researcher interested in studyingsweetpotato finds it difficult to get information needed to support his/her research.

Conclusion

Considering the various constraints, the following actions are suggested forimprovement of the status of Conservation and Documentation of Sweetpotato GeneticResources in Irian Jaya.

• Contributions from individual researchers have indicated that there are stillsweetpotato growing areas unexplored. So it is suggested that further explorationand collecting may be undertaken in such areas.

• In order to improve documentation on sweetpotato genetic resources, a dataexchange system between various parties involved in the conservation of geneticresources, especially between those who hold Irian Jaya accessions, must be set up.

• In vitro conservation is a potential complementary method to field genebank. It needsless space and labour. However, the cost of setting up this type of conservation wouldbe undoubtedly high. Besides, it needs educated and skilled staff to maintain thecollection. Support from other institutions to improve staff skills, and to raise fundto set up and maintain accessions is needed.

• In order to produce more productive and useful research, research policy must beformulated by the RSRC.

ReferencesGuaf, E., P.Van Wijmeersh and M. Otto. 1996. Conservation of sweetpotato germplasm in

Papua New Guinea. Pp. 35–40 in the Formation of a Network for the Conservationof Sweetpotato Biodiversity in Asia, Proceedings of the Workshop (V. Ramanatha Rao,ed.) Bogor, Indonesia. 1–5 February 1996. CIP and IPGRI. IPGRI-APO, Singapore.

Jusuf, M., Y.Widodo, St.A. Rahayuningsih and Suyamto. 1996. Sweetpotato geneticresources in Indonesia. Status and future outlook. Pp 41–45 in Proceedings of theWorkshop on the Formation of a Network for the Conservation of SweetpotatoBiodiversity in Asia. CIP, Bogor, Indonesia, 30 April–5 May 1996 (V. RamanathaRao, ed.). CIP, Bogor and IPGRI. IPGRI-APO, Singaproe.


Matanubun, H., F.A. Paiki and S. Taberima (eds.)1991. Eksplorasi I. Ubi-ubian diKabupaten Paniai dan Kabupaten Biak Numfor, Irian Jaya. Pusat Studi Ubi-ubianUncen. 51p.

Paiki, F.A. 1993. Laporan Penelitian Karakterisasi Morfologi Beberapa Kultivar Ubijalar(Ipomoea batatas (L) Lam) Irian Jaya. Faperta Uncen. 42p.

Prain, G. 1999. The Maintenance and Utilization of Irian Jaya’s Sweetpotato GeneticResources, Progress Report, May 1997–April 1999. CIP, Bogor.

Sawor, T.P. Chadikun, et al. 1993, Interdisciplinary collection of Ipomea batatas L.Germplasm and Associated Indigeneous Knowledge in Anggi, Irian Jaya, Indonesia.Users’ Perspective with Agricultural Research and Development (UPWARD),Universitas Anderawasih, International Potato Center (CIP)

Schneider, J., C. A. Widyastuti and M. Djazuli (eds.). 1993. Sweetpotato in the BaliemValley area, Irian Jaya, A report on collection on study of sweetpotato germplasm,April–May 1993. CIP and RTCRC. 54 p.

Yaku, A., S. Taberima and N.L. Mawikere. 1994. Identifikasi Morfologi Beberapa KultivarUbijalar Asal Dataran Tinggi Jayawijaya Irian Jaya. Faperta Uncen. 33p.

39

Sweetpotato Germplasm Conservation and Breeding in CIP-ESEAP

Tjintokohadi, N.L. Ningsih and Il Gin MokInternational Potato Centre (CIP), Regional Office for East, Southeast Asia and the Pacific(ESEAP), Kebun Percobaan Muara, Jl. Raya Ciapus, Bogor 16610, Indonesia

Introduction

Conservation of genetic diversity within a crop species is the basis of all varietalimprovement. Therefore, collecting and conserving farmers’ varieties is an essentialactivity before disseminating improved varieties. CIP-ESEAP has been working forgermplasm conservation since 1990. The activity includes collecting, maintenance, andevaluation of germplasm.

Extensive evaluation focused on useful characteristics for crop improvement suchas resistance to scab, flowering and dry matter content. In practice, we groupedaccessions and combined with introduced seeds from various research institutes intoseveral subsets for seed production at polycross nurseries. The subsets included highyield, high dry matter content, scab resistance, dark flesh colour, high pigmentation,and earliness. Part of the seeds collected was used in breeding to develop good variety.

Distribution of advanced breeding clones as well as selected germplasm accessionsresulted in several new varieties. CIP-ESEAP produced more than 20 improved breedingclones. These improved breeding clones have been distributed to many farmers,institutes, NGO’s and private companies in Indonesia.

Collection

As the number of germplasm accessions has increased from collaborative efforts of CIP,CRIFC, RILET and RTCRC since 1990, 1441 accessions were collected from variousregions of Indonesia. The focus of conservation is on the landrace or variety grownby farmers over a long period of time. An overview of the accumulated collection ispresented in Table 1. Fig. 1 indicates the areas covered by the expedition team. Accessionswere obtained through collecting trips to the main production areas; for conveniencethey will be referred to as Indonesian germplasm, not including the accessions collectedin Irian Jaya. During the expeditions to Irian Jaya, the interdisciplinary team alsorecorded farmers’ knowledge related to these accessions (Schneider et al. 1993)

All accessions are maintained at Bogor (200 m asl) for Indonesian/Muara germplasm(485 accessions), at RIV Lembang (1250 m asl) for Irian Jaya germplasm (566 accessions)and another back-up of Indonesian germplasm (485 accessions). All accessions fromIrian Jaya were transferred to RILET for conservation in the field. A set of core collectionof Irian germplasm was re-introduced to Anggi under the care of RTCRC.

Table 1. Number of sweetpotato accessions collected in Indonesia and presently maintainedProvince of origin Acc-collected Duplicated MaintainingJava 346 136 210Sumatera 274 121 153Kalimantan 0 0 0Sulawesi 61 20 41Bali,Nusa Tenggara 113 17 96Irian Jaya 499 (+148) 65 419 (+147)Total 1441 372 1046

Note: after eliminating at the Muara GP


Fig. 1 Sites of collecting sweetpotato germplasm in Indonesia

Characterization

Morphological characterization has been carried out for all accessions maintained inour collections. Observation was made 90 days after planting. The method ofmorphological characterization was described by CIP, AVRDC and IBPGR (1991). Thedescriptors present a system of prioritising characters. The colour chart developed atCIP was used to record storage root skin and flesh colour. The characterization wascontinued in the 3 to 5 seasons in the field where all accessions were planted in groupsaccording to the morphological characterization carried out in the previous season. Thegrouping had resulted from a sorting of the data files according to the previous planting.Accessions that resembled each other were planted side by side to facilitate furthercomparison. Accessions with the same morphology were assigned a group number.Field resistance to scab and flowering intensity under field condition were also recorded.

Duplicates were first identified in the Indonesian germplasm and as indicated in Table1, about 294 accessions of this collection were duplicates. Eliminating the duplicate accessionsin the Indonesian germplasm was carried out in 1997. There were not many duplicateaccessions in the Irian Jaya germplasm; it was known that only 65 accessions were duplicates.

Evaluation for dry matter content

The Muara and Irian Jaya germplasm have been harvested several times since their initialcollection. At Bogor, the materials were harvested five months after planting, while atLembang, harvesting took place six to seven months after planting. On harvesting, we firstselected accessions with high yield; only selected accessions were further measured for drymatter content. The results of this process from two sets of germplasm are presented inTable 2a. Most accessions selected had dry matter content in the range of 30–35%. Amongaccessions in the two sets of germplasm, some clones had a dry matter content of about40%, while producing reasonably high yield. These clones become important materials forthe breeding programmes. Many of the Irian accessions did not produce storage roots whenfirst planted at Lembang after their collection and more accessions started to produce storageroots after 2 to 4 clonal generation. Accessions from Irian Jaya, generally lacked orangeflesh colour (Table 2d), there was a tendency that these accessions were also lackedpigmentation on abaxial vein or main vein (Mok 1996).

Resistance to leaf scab

Field resistance to scab was assessed by scoring the symptoms on a scale from 0 (nosymptom) to 4 (severe infection). Observation for scab resistance was carried out seventimes, among 2 sets of germplasm, showed that the Irian germplasm was more resistantto leaf scab than the Muara germplasm. It is highly probable that Irian farmers haveselected accessions since they are cultivating sweetpotato as staple and animal feed

41

in highland, where it rains throughout the year (about 1700–2000 mm). The result ofscab scoring was used for presentation in Table 2b.

The IK recorded during the collecting expedition indicated that farmers in Irian Jaya areusing some sweetpotato varieties for baby food, general human consumption and feed for pigs.

Flowering ability

There was no difference in intensity and frequency distribution between the two groupsof germplasm. The result of flowering observation is presented in Table 2c; 40% ofaccessions collected did not flower under natural conditions. Although only 12%flowered profusely, almost 60% of accessions flowered to a larger or lesser degree. Theintensity of flowering depended very much on the genotype, which was another excellentindicator for duplicate identification, in addition to morphological characterization.

Table 2. Frequency distribution of important characteristics of Muara and Irian Jaya sweetpotatogermplasma) Dry matter content of clones selected based on yield

Muara germplasm Irian Jaya germplasmDM (%) Freq Freq Freq Freq Freq Freq Freq Freq Freq Freq

Sep ‘96 Jun ‘97 Apr ‘98 Oct ‘98 Oct‘99 Jun ‘96 Dec ‘96 Jun ‘97 Jun ‘98 Jul ‘99£ 20.0 0 1 0 0 1 1 1 0 1 120.1–25.0 3 4 9 6 3 1 1 0 0 025.1–30.0 17 15 40 45 20 15 19 1 4 830.1–35.0 13 11 29 26 20 26 59 16 24 2435.1–40.0 3 5 5 6 3 9 22 20 6 4≥ 40.1 0 0 0 0 0 0 0 5 0 0Total 36 36 83 83 47 52 102 42 37 37

b) Resistance to scab disease

Score Definition ReactionFrequency

Muara GP+ Irian GP++

0 No symptom Highly resistant (HR) 125 3011 1–5 stem infected in a plot of Resistant ® 45 61

20 plants2 Many plants infected slightly Moderately 87 12

(5–10% of leaf area) resistant (MR)3 All plants infected moderately Susceptible (S) 104 6

(11–25% of leaf area)4 All plants infected severely Highly 118 1

(>25% of leaf area) susceptible (HS)Total 479 381

+ The maximum value of scab resistance from seven observation between February–May 1991++From the observation 12 July 1995.

c) Flowering intensity

Score DefinitionFrequency

Muara GP+ Irian Jaya GP++

0 No flowering 204 1481 1–3 plants flowering within a plot of 20 plants 117 582 Most of plants with 1–3 flower 93 493 Most of plants with 4–7 flower 44 454 All plants flowering profusely 21 81

Total 479 381+ The maximum value of flowering from seven observations between February–May 1991.++From the observation on July 12, 1995.


d) Storage root flesh colour, predominant colour

Score DefinitionFrequency

Muara GP Irian Jaya GP0 No flowering 204 1481 White 202 272 Cream 85 1763 Dark cream 0 264 Pale yellow 99 875 Dark yellow 18 416 Pale orange 34 67 Intermediate orange 31 38 Dark orange 12 19 Strongly pigmented with anthocyanins 5 6

Total 486 373

Conservation

For conservation, accessions most frequently utilized in the breeding programme fromthe two groups of germplasm are maintained in the RIV station, Lembang (1250 m asl),and at Bogor (200 m asl). They would be constantly evaluated and utilized. They wereusually re-established twice a year, using cuttings obtained directly from the old field.Since 1998, all accessions from Irian Jaya have been transferred to RILET for conservationin the field genebank. A set of core collection of Irian germplasm was re-introducedto Anggi under the care of RTCRC.

Botanical seeds have been collected from the field genebank, through polycross andcontrolled pollination. Accessions were divided into several subsets based on theprevious field evaluation data, for example subsets of high yield, high dry matter content,scab resistance, dark flesh colour, good flowering, high combining ability. In 1994,through collaborative activities of RIFCB and The Ornamental Institute at Cipanas, alarge amount of seed families were collected for further selection in the breedingprogramme (Table 3).

Table 3. Seeds obtained with polycross from germplasm and the ESEAP breeding programme

Group ‘92–1995 1996 1997 1998 1999 TotalSeeds Seeds Seeds Seeds SeedsHigh DM 1 764 106 640 31 294 74 863 74 395 287 956High DM and Yield 134 541 134 541Scab resistance 17 756 7 207 25 115High Pigmentation 27 923 102 573 130 496High Altitude adaptation 46 143 46 143High yielding capacity 2 952 23 300 26 252High specific combining 15 246 148 790 64 036abilityHigh frequency selection 31 300 31 300of dry matterDrought tolerance 454 454Weevil resistance 19 357 19 357Earliness 41 228 41 228Germplasm 38 882 32 221 24 420 71 103Multiplication plot 56 197 56 197Total 104 999 164 266 224 858 265 310 298 813 1 977 781

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Evaluation

We found that many accessions from Muara and Irian Jaya have reasonably high yield.Each season, accessions were first selected by yield and then by dry matter content.These accessions were not of extremely high dry matter content, but they demonstrateda good yield potential in Indonesia. The accessions in Tables 4a and 4b were selectedbased on their performance for at least two seasons. The accessions W0387 (Kambani),W0345 (Iloka), W0139 (Toweko), W0116 (Helalekue), W0446 (Waimunki), W0331 (Kinta),W0200 (Here-here), W0223 (Umakmbi), W0046 (Gelanggel), W0195 (Ketelale), B0097(Biru), W0126 (Kali urang), B0160 (Unknown), S0068 (Unknown), B0367 (Unknown),S0034 (Unknown) and S0083 (Gowi Raha) were constantly high in yield and dry mattercontent over 2–5 seasons. These accessions have an advantage in selecting local varietiesfor processing.

Table 4a. Accessions selected from Irian Jaya germplasm for high dry matter content andhigh yield potential

Total

Acc No VarietyYield % DM Average-

Jul ’99 DM (%)(t ha-1) Jun ’96 Jul ’97 Dec ’97 Jun ’98 Jul ’99

W0387 Kambani 22.7 28.9 33.0 32.6 34.9 32.3W0345 Iloka 16.6 33.8 33.8 34.8 34.1W0139 Toweko 14.8 37.1 34.0 37.5 36.2W0116 Helaleke 14.2 39.3 41.3 37.4 39.3W0446 Waimunki 13.9 32.4 37.1 31.8 34.6 32.7 33.7W0331 Kinta 13.4 34.4 35.5 33.6 34.1 36.0 34.7W0200 Here-here 12.8 36.0 33.0 31.6 33.5W0223 Umakmbi 11.8 41.0 34.6 39.0 38.2W0046 Gelonggel 11.5 34.9 39.3 35.3 34.1 35.9W0195 Ketelale 11.9 38.0 32.4 29.5 30.6 32.6

Table 4b. Accessions selected from Muara germplasm for high dry matter content and highyield potential

Total

Acc No VarietyYield % DM Average-

Jul ’99 DM (%)(t ha) Sep ’96 Jun ’97 Sep ’97 Jun ’98 Oct ’99

B0097 Biru 23.0 36.6 36.0 26.5 31.6 32.6B0126 Kali Urang 24.7 36.6 25.9 25.5 29.3B0160 Unknown 18.2 34.0 29.2 32.1 30.4 31.4S0068 Unknown 17.7 30.4 25.6 31.4 29.1B0367 Unknown 15.5 32.1 34.3 30.3 32.2S0034 Unknown 22.6 31.6 26.2 26.5 32.8 29.3S0083 Gowi Raha 24.6 27.3 29.0 36.8 24.9 29.5

Documentation

CIP-ESEAP uses the following definitions in genetic resources documentation, whichwere stored in a computerized d-base: Passport accession data file, Passport seeds datafile, Characterization data file, and Digital image of leaf, stem, and storage roots. Theseindividual files were linked and it becomes thus possible to select accession for anycombination of desired data. It is also useful in judging the worth of a variety to assessthe agronomic and utilization potential of an accession.


Sweetpotato breeding for high dry matter content

Increasing dry matter content is the primary objective for the sweetpotato breedingprogramme in the ESEAP region. Since 1990, a large number of CIP pathogen testedclones have been evaluated in Bogor and at other sites in Indonesia. However, theyhave low dry matter content or poor adaptability, but good agronomic characters. Weare now combining this CIP germplasm with locally important cultivars in a recurrentselection scheme for long-term population improvement.

Botanical seeds introduced from various sources, including CIP headquarters, otherregional breeding programmes, China, Japan, and the Philippines have been intensivelyevaluated and selected (Table 5). From 1993 to 1995, about 90 advanced breeding cloneswere selected for high DM content, and high yield in Bogor. These clones were againevaluated at Lembang and Malang to select the most suitable varieties for starchproduction. As a result, there are about 20 advanced breeding clones (Table 7). Theadvanced breeding clones also have many useful traits such as resistance to scab, whiteor cream flesh colour, and good root shape. The most promising advanced breedingclones are listed in Table 6. They have stable yield in different environments, high drymatter content, and resistance to scab.

Based on overall performance, the four best clones were selected for starchprocessing, i.e. AB94001.8 (CIP-2), a selection from Japanese seed families, and the otherthree clones from CIP-HQ. All clones are high yielding and high in DM and starchcontents. These advanced breeding clones have been distributed to many farmers,institutes, NGOs and private companies in Indonesia.

Table 5. Origin of advanced breeding clones selected at Bogor in 1993–95. All materials wereinitially introduced as botanical seed

Source Advanced breeding clones Families evaluatedselected from the source at Bogor

AVRDC 1 42XSPRC, GAAS, China 16 62NARC, Japan 31 15Philippines (ASPRAD) 1 53MSU, USA 0 18CIP-HQ 37 63CIP-SSA 5 38CIP-ESEAP 4 78CIP-SWA 0 5Total 95 374

Table 6a. Best clones selected for high dry matter content and yield

Yield t/ha Dry matter content %Starch

Skin FleshTop

Clone content % weightMalang Bogor Lembang Malang Bogor Lembang Lembang

colour colourt/ha

B94001.8 30.4 14.1 25.9 37.8 34.8 37.1 25.4 Cream White 35.0AB94065.4 27.5 15.6 24.3 37.2 37.3 33.8 0.0 Cream White 29.4AB94078.1 26.2 18.5 18.4 39.4 40.4 36.7 25.1 Red White 14.4AB94079.1 28.6 14.8 17.9 38.7 38.8 36.0 27.0 Cream White 27.8

45

Table 6b. Starch productivity at Lembang and MalangClone Yield at Yield at Starch Starch Starch

Lembang Malang content production at production att/ha t/ha % Lembang t/ha Malang t/ha

AB94001.8 25.9 30.4 25.4 6.58 7.72AB94065.4 24.3 27.5 – – –AB94078.1 18.4 26.2 25.1 4.62 6.58AB94079.1 17.9 28.6 27.0 4.83 7.72

Table 6c. Origins of selected cloneClone Source Female MaleAB94001.8 Japan Kusyu 102 Kanto 106AB94065.4 CIP 194064 PRMG 1-003 PC9302 REND.MSAB94078.1 CIP 194101 JPKY 2-019 OP9301 PC93AB94079.1 CIP 193005 JPKY 7-014 OP9301 PC93

Table 7. Clones selected for overall average performances with high dry matter and high yieldingpotential at different environment

DM%DM

Yield t/haYield

No Clone Bogor Lembang Malang Bogor Lembang Malang Shape SkinSep Apr Aug

AveSep Apr Aug

Ave

1 AB95012.4 34.4 34.2 30.4 33.0 20.0 31.4 11.6 21.0 Good L.yellow2 AB94065.6 38.8 38.4 32.8 36.7 18.6 32.2 8.5 19.8 Good Yellow

3 AB94065.10 34.1 37.2 30.9 34.1 21.2 26.8 11.0 19.7 Round-oval Cream4 BB93521.5 26.8 31.3 30.4 29.5 19.5 29.6 8.9 19.3 Small Red5 AB95007.2 31.7 33.6 30.0 31.8 17.1 31.4 8.7 19.1 Oval Cream

6 AB94078.1 35.2 38.9 33.9 36.0 19.0 26.4 10.1 18.5 Long Red7 AB94065.9 34.2 39.1 33.0 35.4 16.0 32.7 6.7 18.5 Round L.yellow8 AB94065.1 36.5 36.8 35.6 36.3 16.7 30.9 6.2 17.9 Long L.yellow

9 AB94001.8 34.8 39.2 33.0 35.7 15.0 25.9 12.6 17.8 Thin-small Red10 AB95108.3 32.7 36.5 32.3 33.8 13.6 31.0 8.8 17.8 Small Red11 AB94079.1 35.2 35.2 34.3 34.9 10.2 32.4 10.3 17.6 Big-round Cream

12 BB94572.2 35.7 37.0 34.8 35.8 13.3 29.3 8.7 17.1 Medium L.yellow13 AB95012.3 36.0 35.7 32.5 34.7 12.0 31.1 6.4 16.5 Large-oval Red14 AB94065.5 34.2 36.6 34.0 34.9 15.1 27.4 6.1 16.2 Long-oval Red

15 AB95008.3 34.6 33.6 33.7 34.0 11.6 27.4 8.7 15.9 Medium-oval Yellow16 AB94065.7 32.5 35.1 34.3 34.0 10.7 25.1 8.8 14.9 Round Pink17 AB94080.3 36.3 38.2 35.0 36.5 10.5 24.0 6.0 13.5 Oval Yellow

18 AB94085.5 33.8 39.9 36.0 36.5 13.2 21.0 4.0 12.7 Long-oval L.yellow19 AB94065.8 32.0 34.0 31.5 32.5 13.6 18.6 5.7 12.6 Round Red20 AB94079.6 38.4 37.3 35.9 37.2 10.8 20.0 6.9 12.6 Round Pink

21 AB95002.6 33.0 38.5 34.6 35.4 4.0 26.7 6.7 12.5 Oval Red22 AB95002.7 35.0 37.9 33.1 35.3 1.4 28.1 6.7 12.0 Oval Cream23 AB95002.3 34.5 36.8 33.6 35.0 8.6 21.4 5.9 12.0 Oval Red

24 AB94065.2 31.8 37.6 30.9 33.4 8.2 22.8 4.5 11.8 Oval Red25 AB94065.4 30.9 35.4 30.7 32.3 6.0 22.2 4.0 10.7 Long-oval Red

Evaluated in Bogor-Lembang, and Malang in September, June–September 1999 (Bogor), November1997–April 1998 (Lembang), April–August 1998(Malang)


On-going trials

In the ESEAP region, there are several on-going trials. The trials are conducted at threeenvironments, i.e. poor soil in humid tropics (Bogor), 200 m asl; cooler climate inhighland (Lembang), 1200 m asl; and high fertile soil (Malang), 500 m asl. The entriesused in these trials were generated through polycross. The maternal parent came fromgermplasm which were sorted based on their specific character, flesh colour, high drymatter content and yield potential. The accessions are used as maternal parent to producebotanical seeds (Table 8).

Table 8. The accessions used as maternal parents in polycrossACC-No Variety Source Potential charactersB0571 Unknown OP of Indonesia germplasm EarlinessB0572 Muntul IR OP of Indonesia germplasm EarlinessB0191 Keduk OP of Indonesia germplasm EarlinessB0068 SQ-27 OP of Indonesia germplasm High dry matter contentW0232 Karubaka OP of Irian Jaya germplasm Dark flesh colourB0381 Unknown OP of Indonesia germplasm Dark flesh colourW0185 Ekenhili OP of Irian Jaya germplasm Dark flesh colourW0228 Yoban OP of Irian Jaya germplasm High dry matter contentW0100 Ndulanom OP of Irian Jaya germplasm Dark flesh colourW0124 Korwambi OP of Irian Jaya germplasm Dark flesh colourB0126 Kali Urang OP of Indonesia germplasm High dry matter contentB0107 Dayak OP of Indonesia germplasm High dry matter contentS0221 Unknown OP of Indonesia germplasm Dark flesh colourW0152 Yuaiken OP of Irian Jaya germplasm Dark flesh colour

Future plans

• Continuing to conserve the botanical seeds in the polycross, the accessions can bedivided, based on current specific usage, high vigour, yield, earliness, droughttolerance and table consumption.

• Transferring the responsibility of further conservation of the germplasm to the careof the Indonesian institutions working on sweetpotato: RILET, RIFCB and RCTRC.

• Publication and distribution of germplasm, and the advanced breeding clonesthrough the internet and brochures.

ReferencesCIP, AVRDC and IBPGR. 1991. Descriptors for sweetpotato (Z. Huaman, ed.). IBPGR,

Rome.Mok, I.G. Sweetpotato Germplasm Conservation in ESEAP in Progress Report 1999.

ESEAP-Sweetpotato Breeding. Bogor, Indonesia.Schneider, J., C. A. Widyastuti and M. Djazuli (eds.). 1993. Sweetpotato in the Baleim

Valley area, Irian Jaya. A report on collection on study of sweetpotato germplasm,April–May 1993. CIP and RTCRC. 54p.

47

Recent Progress on the Conservation and Use of Sweetpotato inthe Philippines

Algerico M. Mariscal, Jose L. Bacusmo, Villaluz Z. Acedo and Enrique AbogadiePhilippine Rootcrop Research and Training Centre, VISCA, Leyte, Philippines

Introduction

Sweetpotato ranks second to cassava among rootcrops in the country in terms of areaand production. For the last 10 years, the average area planted with sweetpotato is144 300 ha, with mean production of 689 100 metric tons. It is generally grown in marginaland harsh environments and adapted to several cropping systems. Generally,sweetpotato is widely grown by subsistence and commercial farmers in all agro-ecological conditions.

Ninety percent (90%) of the total production of sweetpotato is consumed as foodand ten percent (10%) are utilized for feed, starch and waste. Recent developments havefavoured the utilization of sweetpotato for animal feed and starch.

The sweetpotato genetic resources in the country are diverse. Farmers’ varieties aswell as introduced and recommended varieties are now grown in the countryside.However, with natural calamities, such as long dry spells, heavy rains and typhoons,it is inevitable that some of the genetic resources become extinct or go missing, resultingin genetic erosion of sweetpotato genetic resources in the country. As such, concernedgovernment agencies have collected and maintained sweetpotato genetic resources inthe field genebanks and in the laboratory in the form of tissue culture for conservationand use. The largest genebank of sweetpotato is located at the Philippine RootcropResearch and Training Centre (PRCRTC) at the Visayas State College of Agriculture(ViSCA), Baybay, Leyte. Other agencies that maintain sweetpotato genetic resourcesare the Institute of Plant Breeding (IPB) of the University of the Philippines at Los Baños(UPLB), College, Laguna, and the Northern Philippine Rootcrop Research and TrainingCentre (NPRCRTC) of Benguet State University in La Trinidad, Benguet.(Bacusmo etal. 1995)

Status of sweetpotato conservation

Three years ago (May 1996), participants from 11 countries in Asia gathered togetherin Bogor, Indonesia, through the efforts of CIP and IPGRI in order to discuss vital issueson the conservation of sweetpotato genetic resources and this led to the formation ofa sweetpotato network. With collective effort and a common desire, the Asian Networkfor Sweetpotato Genetic Resources (ANSWER) was founded during that meeting. Thefirst major activity of the network was the “ANSWER training course on maintenance,characterization, and duplicate identification of Ipomoea batatas collection” held atPRCRTC, ViSCA, Baybay, Leyte, during September 1–6, 1997. Six ANSWER membercountries (Philippines, Japan, Indonesia, Malaysia, Vietnam and Thailand) participatedin the course and the expertise was provided by CIP/IPGRI. Other member countriescould not participate due to communication and travel processing problems. Duringthe training, practicum on the morphological characterization based on CIP/IPGRIdescriptors list was undertaken including its subsequent statistical analysis for duplicateidentification. Each participating country was expected to apply the knowledge learntat the course for characterization and duplicate identification of their respectivesweetpotato genetic resources collections. Using such a procedure, the following is thecurrent status of sweetpotato genetic resources in the country.


Current number of clonal accessions maintained in field genebank

In 1996, the total number of sweetpotato collections in the Philippines reached up to2855 (Table 1), the majority of which are conserved in PRCRTC. After the ANSWERtraining, the accessions were subjected to morphological characterization and theavailable materials are only 1815 accessions. In PRCRTC, the reduction of number from1402 to 931 is attributed to severe environmental stresses, like long dry periods, heavyrains, pests and diseases. Losses were observed in the field genebank through continuousreplanting. In NPRCRTC of Benguet, the reduction of number was due to the eliminationof duplicates by the curator based on CIP/IPGRI descriptors list. It was found thatthe majority of the accessions were duplicates. In IPB and UPLB, no figure for recentsweetpotato accession was provided.

Table 1. Total number of sweetpotato clonal accessions in the Philippines (1999)

AgencyNumber of accessions

Collected AvailablePhilippine Rootcrop Research and Training Centre, 1402 931ViSCA, Baybay, LeyteNorthern Philippine Rootcrop Research And Training 653 105Centre, BSU, La Trinidad, BenguetInstitute of Plant Breeding UPLB, College, Laguna 800 800*Total collection 2885 1815

* No information as to the number of accessions available.

PRCRTC, IPB and NPRCRTC are still in the process of field evaluation of thecharacterized accessions for further verification of duplicates. In PRCRTC, thegermplasm collection is composed of registered cultivars, native varieties, introducedcultivars and hybrids (Table 2). Of a total of 1402 accessions, the registered cultivarsaccounted for 1.5%, native varieties 80%, introduced cultivars 17% and hybrids 1.9%.After these materials are fully characterized, it is expected that a large number ofduplicates may be identified.

Table 2. Breakdown of the number of germplasmcollection of PRCRTC (1999)

Source 1996 1999Registered cultivars 19 21Local cultivars 1118 904Introduced cultivars 238Hybrids 27 6Total 1402 931

Current number of accessions with passport data and morphologicalcharacterization

Of the total number of 1402 accessions from PRCRTC, 1258 have passport data andthese data have been submitted to CIP, Peru, for developing of the database. With theuse of CIP/IPGRI descriptors list, 550 accessions were thoroughly characterized andall the morphological and agronomic data are available. Germplasm collections ofNPRCRTC and UPLB and passport data are not reported yet. Morphologicalcharacterization and evaluation are still an on-going activity. (Mariscal 1998)

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Number of accessions with evaluation data (yield, pest and disease)

As far as the evaluation is concerned, only 50% of the collections in PRCRTC werepreviously evaluated for yield. Variation in yield ranged from 1 to 25 t/ha. Screeningfor weevil and scab resistance and tolerance to acidic and shade conditions were alsodone. Recently all the collections were planted in a single row at 10 plants per rowto further evaluate the agronomic characteristics of the collection aside frommorphological characterization for duplicates identification. The other agenciesmaintaining collection may also do their respective evaluation, especially those, whichparticipated in the ANSWER training.

Number of accessions having farmers’ indigenous knowledge

On this aspect, not much work has been done at the centre. The Users’ Perspectivewith Agricultural Research and Development (UPWARD) has studied and documentedfarmers’ indigenous knowledge on sweetpotato variety identification and maintenancein southern Mindanao (Piniero 1995). The study focused on “memory banking” and“community-based genebanking”. This aspect needs to be worked out further in orderto utilize the farmers’ knowledge as complementary tool in genetic conservation infarmers’ fields.

Number of accessions maintained in vitro

To back up field collection of important accessions, in vitro (tissue culture) maintenanceis done. Due to lack of financial support, only a very minimal number of accessionswere maintained in the laboratory. In 1995, the PRCRTC tissue culture laboratorymaintained 155 accessions (Table 3) broken down as follows: 9 registered cultivars, 64CIP materials and 82 crosses from I. trifida x I. batatas. Lately, a number of CIP materialsand the hybrids were found missing due to contamination and death of plants upontransfer to the greenhouse. Losses are also attributed to lack of funds. Recently, thenumber of accessions maintained in vitro is only 82 but 37 farmers’ varieties are includedin vitro. At UPLB, 67 accessions are maintained in vitro.

A large proportion of field genebank collection is lost due to biotic and abioticstresses. It is necessary that, after thorough characterization and elimination ofduplicates, the important genetic materials are maintained in vitro.

Table 3. Total number of collections stored in vitro (1999)Agency/source 1994 1999PRCRTCRegistered cultivars 9 9Farmer’s varieties – 37CIP materials 64 25Introductions (Japan) – 5Hybrids (I. batatas x I. trifida) 82 6Total for PRCRTC 155 82

IPB, UPLBGeneral collections 67 67*Total accessions 222 149

* No new information about the actual number of accessions in vitro.


Number of accessions having molecular fingerprints

This level of evaluation entails a large amount of money aside from needed equipment.With a small support from IPGRI, a part of the farmers’ varieties collection (19 cultivars)were sent to UPM, Malaysia, for DNA analysis in order to determine the level of diversityof the farmers’ varieties at molecular level. Results of this study are awaited.

Documentation

At the start of massive collecting of sweetpotato germplasm, information on collectedmaterials was kept in paper files. It was only when the computer facilities becameavailable at the centre that passport data and morphological characterization data weretransferred to computerized databases. This was further strengthened after the ANSWERtraining in last September of 1997 that demonstrated the software to handle databaseon passport, morphological and evaluation data. All important information related togermplasm collection, especially on agronomic evaluation, will be entered into computerdatabase. Another cycle of evaluation of all the germplasm collection will be undertakento determine the performance of the genetic materials under various conditions.

Utilization of germplasm collection

Success in the breeding programme depends on the wide genetic diversity in theavailable genetic resources. Thus, the first major step in any breeding programme isto assemble a diverse germplasm collection. Germplasm collection caters to two-foldpurposes, one for the preservation of genetic materials and the other for the developmentof new improved varieties.

For more than 20 years of its existence, PRCRTC and its cooperating stationsdeveloped 21 registered improved varieties by utilizing the available genetic materials.Since the start of the breeding programme, 14% of the total germplasm collection wereused for the development of improved varieties.

The ex situ conserved materials also provided the needed farmers’ varieties in thearea where they are no longer available. This is manifested by some farmers in Lanaodel Norte who envisioned having the variety previously grown in their area but is nolonger available in that locality. Thus, with germplasm available, one can easily supplythe farmers the needed native varieties.

Field genebank management

All the sweetpotato collections of PRCRTC are presently maintained in 14-inch claypots, which are partially buried in the open field to allow irrigation. The accessionsare grouped together according to the shape and colour of the leaves. Each genotypein the pot is renewed/replanted every 3 months. Aside from pots, separate single-rowplots per accessions are maintained in a separate field for evaluation and characterizationpurposes. Additionally this serves as back up for pot maintenance. This procedure islaborious, especially when a large number of accessions are maintained (Mariscal andLopez 1996)

In situ conservation has been identified to be a complementary method for long-term conservation. However, in a strict sense, this type is not applicable to sweetpotatobecause this crop cannot survive in the field without human intervention. For thispurpose, on-farm conservation may still fall under in situ conservation. This methodwas introduced in the southern Philippines by UPWARD (Prain and Piniero 1996).Farmers themselves are the plant curators in their own fields. They are given thematerials, native as well improved, for them to maintain. In the beginning the project

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was satisfactory, but as the cropping patterns in the area changed, coupled with socialproblems, a number of germplasm materials were no longer available. However, whenthe demand for the sweetpotato products is high, farmers tend to acquire genetic materialto maintain and plant. Thus, in situ/on-farm conservation should not be taken as anindependent entity but should be a complementary component in the overall germplasmconservation effort.

An attempt to establish a core collection of sweetpotato was done with the helpof IPGRI. Three hundred accessions representing all parts of the collection site wererandomly taken and all the morphological data were gathered from the database.Detailed analysis from this group will be made using available statistical tools. At themoment this is to be pursued and studied carefully if this number truly represents theentire germplasm collection in the country.

Because of the risk and labour of vegetative maintenance of sweetpotato germplasm,IPGRI provided a small fund to study the possible production of a number of botanicalseeds per accession that would retain the maternal genetic composition. Initial resultsrevealed that, using low to high flowering accessions, selfed seeds were produced withvarying percentages. Offsprings obtained from the selfed seeds have greater percentageof maternal traits as compared to offsprings from the open pollinated seeds. The resultneeds to be further confirmed by additional studies because heavy rains affected theevaluation phase of the offsprings from both self and open pollinations. From the initialresults, there seems to be an indication that botanical seed can be an additional wayof conserving sweetpotato genetic resources.

Problems and constraints of field genebank management

It is a common experience of all plant curators that the maintenance of vegetativematerials in the field is vulnerable to many stresses and results in loss of importantgenetic materials. This is mainly because of the exposure of the plants to environmentalextremes. PRCRTC has been maintaining sweetpotato germplasm in the field for morethan 20 years and tremendous loss of genetic materials has been observed. In records,PRCRTC recently has a total collection of 1402 accessions and the remaining availableclonal materials come to only 931, which include some duplicate accessions. Thus, asidefrom the loss of the important materials, the costs of collecting as well as the maintenanceborne by the government and other funding agencies are wasted. Field genebankmanagement therefore, has the following problems:1. High cost of maintenance2. Biotic stress (pests and diseases) and abiotic stress (droughts, typhoons, socio-

political factors, and economic factors)3. Duplicates are still maintained, thus maintaining large collection4. Genetic integrity of the accessions has not been ascertained5. Lack of financial support.

Ways to overcome constraints in field genebank management

Due to several problems encountered in field genebank maintenance, an alternativeconservation strategy is needed. These are the following:1. In vitro maintenance – Materials that are already characterized and ascertained as

being different from each other shall be put in in vitro culture. In this case a tissueculture laboratory able to handle the materials is needed. PRCRTC, after thoroughlycharacterizing the collections and ensuring that duplicates are already eliminated,shall maintain important collections in vitro.


2. On-farm conservation (in situ) – In areas where indigenous varieties are maintainedby farmers, they shall be tapped and given recognition and be backed up by exsitu conservation. This is a complementary strategy of genetic conservation.

3. The use of botanical seed – Conservation by seed seems to be very convenient tohandle and to process sweetpotato germplasm resources. An intensive study on thisaspect is needed considering the high ploidy level of sweetpotato.

Possible contributions from the network to overcome constraints

Considering that the network is a group of people or organizations that agree to shareinformation or other resources in such a way that greater benefit is derived, the networkcan have the following contributions:1. Sharing of information related to field genebank management2. Training on field genebank management3. Safety duplications4. Creation of regional genebank5. Germplasm exchange6. Clean up of materials.

Recommendations

To have a dynamic germplasm collection for food security, the following arerecommended:1. Germplasm maintenance shall be fully supported by the government in financial

and policy matters2. The collections shall be fully characterized and only different morphotypes

maintained3. Training shall be provided and core collections developed4. Important genetic materials shall be placed in vitro for long term conservation5. Study shall be made on the possibility of conserving botanical seed6. Genetic materials shall be cleaned up7. Technical backstopping from CIP/IPGRI shall be given8. Exchange of germplasm shall be facilitated.

ReferencesBacusmo, J.L., V.Z. Acedo, A.M. Mariscal and M.Z. Oracion. 1995. Sweetpotato genetic

resources in the Philippines. Pp. 105–114 in Root and Tuber Crops. Proceedings of anInternational Workshop of Genetic Resources. Tsukuba, Japan. March 15–17 1994.

Mariscal, A.M. 1998. Sweetpotato breeding and genetic resources conservation in thePhilippines. Pp. 99–118 in Sweetpotato Genetic Resources Conservation and Usein Asia (R.T. Sanico, ed). Proceedings of the MAFF/PRCRTC InternationalWorkshop. Baybay, Leyte, Philippines. MAFF, Japan

Mariscal, A.M. and E.L. Lopez. 1996. The utilization of Asian sweetpotato biodiversityin breeding in the Philippines. Pp. 27–34 in Proceedings of the Workshop on theFormation of a Network for the Conservation of Sweetpotato Biodiversity in Asia.Bogor, Indonesia. 1–5 May 1996 (V. Ramanatha Rao, ed.). IPGRI-APO, Singapore.

Piniero, M. 1995. Methodologies for documenting user’s indigenous knowledge insweetpotato varieties and conservation of rootcrop genetic resources. Pp. 27–33 inIndigenous Knowledge in Conservation of Crop Genetic Resources. Proceedingsof an international workshop. Bogor, Indonesia. Jan. 30–Feb. 3, 1995 (Schneider,ed.). CIP-ESEAP, Bogor, Indonesia.

Prain, G. and M. Piniero. 1996. Communities as Curators of Plant Genetic Resources.The Case of Rootcrop Conservation in the Philippines. IDRC-UPWARD Project.

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Conservation and Use of Sweetpotato in Thailand

Narin PoolpermPhichit Horticultural Research Centre, Department of Agriculture, Phichit, 66000,Thailand

Introduction

Sweetpotato is an important food crop, ranking third after cassava and potato inThailand. It is grown all over the country. The planting area of sweetpotato increasedfrom 6530 ha in 1996 to 8580 ha in 1998. The average production was 15.5 t/ha. About95% of the production was for human food as desserts, snacks and main dishes and5% for animal feed.

Status of sweetpotato germplasm

The collecting and conservation of sweetpotato germplasm are undertaken bygovernment agencies while farmers conserve them on farms by growing themcontinuously. Many accessions have been collected and are conserved in the governmentagencies but a few farmers’ cultivars are yet to be collected. One of the governmentagencies is Phichit Horticultural Research Centre, Department of Agriculture. It is inthe lower north of Thailand and 350 km from Bangkok. By 1999, Phichit HorticulturalResearch Centre had collected 365 accessions of sweetpotato, of which 47 accessionswere native cultivars, 35 introduced, 275 breeding lines and 8 released varieties.

ANSWER Network

Germplasm conservation of sweetpotato in Thailand

Germplasm conservation in the field

Germplasm conservation in the field is the most practical method and can be dividedinto two types.

Ex situ maintenance is done in Phichit Horticultural Research Centre, by plantingsweetpotato in plots of 1x3 m with 30x100 cm spacing. Ten cuttings are planted in eachplot. Harvesting is done after four months. Screening for pest and disease resistanceand determination of quality are carried out by using five plants per plot. The otherfive plants are used as source of apical cuttings for replanting in the new location everyfive months. Fertilizer application and chemical spraying are carried out as needed.

In situ germplasm maintenance is done in the farmers’ fields, especially of thosecultivars grown for commercial purposes. The farmers’ expertise is considerable oncultivars that are part of their everyday work. They select sweetpotato types themselvesby using criteria such as the market requirements and their preferences. Each farmerconserves 1–3 accessions, which are either landraces or promising accessions. Thefarmers consume or sell the storage roots, and maintain small plots of 4x6 m near theirhomes or water resources as a source of propagules. Each accession has 2–5 plots.Fertilizer application and chemical spraying for pests and diseases are done occasionally.At the onset commercial sweetpotato fields range in size from 0.5 to 5 ha.


Conservation as botanical seeds

This form of conservation started in Thailand in 1997 after the 1996 workshop onsweetpotato by CIP and IPGRI in Bogor, Indonesia, by using the seeds from openpollination of rarely used and flowering cultivars. Healthy seeds from the same clonesor the same plants are kept at 5% moisture content in foil packets, labelled with name,location and date, and then kept in a temperature controlled room of 5 ˚C. Botanicalseeds of 50 accessions were conserved at Phichit Horticultural Research Centre in 1999.

Other conservation methods, such as the storage of roots and in vitro maintenance,are not used in Thailand because of the high cost. It is hoped that an in vitro conservationmethod will be developed to safeguard important accessions from the risk of diseasesand other damages. In vitro method is still the best way for many countries to exchangegermplasm.

Problems of sweetpotato germplasm conservation

Lack of financial support:Thailand gives priority to field crop and fruit research. Sweetpotato is nearly at theend of the national priority ranking, after rice, sugar cane, fruits and other crops.Researchers have to do research on these priority species before undertaking any researchon sweetpotato.

High cost of large field collection:Large field collections are costly and affected by maintenance problems such as theoccurrences of pests, droughts and floods.

Problem solving methods

Minimize the conservation

It is an improvement to keep the number of germplasm accessions to the minimumto reduce costs. This can be done by eliminating duplicate accessions and undesirablebreeding lines such as the lines that have no resistance to pests, are low yielding, andof poor quality or late maturing.

Minimize plot size

Before the meeting of the ANSWER Network in 1996, the plot size of sweetpotato inthe conservation field consisted of 1x6 m plots with 20 plants per plot. After the meeting,the plot size was reduced to 1x3 m, with 10 plants per plot and turning the vine everymonth.

Additionally, the method of conservation of seeds of rarely used and floweringaccessions was instituted.• Encourage farmers to grow their preferred accessions for home consumption and

to grow promising accessions of the government for commerce, and maintainsweetpotato germplasm at the farm.

• Resort to use other financial resources to support conservation activities. Manyresearch projects are done on chilli, taro, bamboo shoots and jackfruit. Some resourcesfrom these projects, such as materials and labour, are used in sweetpotato germplasmconservation.

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Current number of clonal accessions as compared with that of the last 3 years (1996-1998)

Phichit Horticultural Research Centre collected and conserved about 2979 accessionsof native cultivars, and introduced cultivars, breeding lines and released varieties in1996. The duplicate accessions were eliminated; the number of accessions collected andconserved decreased to 1500 in 1997, to 750 in 1998 and to 365 in 1999. The duplicateaccessions of native cultivars were reduced to 47 in 1999. About 35 accessions that wereeither late maturing, or low yielding, or non-resistant to pests or introductions thatwere not required for the market were eliminated in 1999. About 275 breeding linesfrom Phichit Horticultural Research Centre and introduced ones from SAPPRAD andCIP with similar characteristics were also eliminated. Farmers were encouraged to growfor commerce eight released varieties from breeding or introduced cultivars that wereof high yield, good quality as per the requirement of the market, resistant to pests andearly maturing (Table 1).

Table 1. Number of sweetpotato accessions conserved inThailand from 1996 to1999

SourceNumber of accessions

1996 1997 1998 1999Native cultivars 25 25 27 47Introduced cultivars 64 35 35 35Breeding lines 2885 1435 682 275Released varieties 4 5 6 8Total 2979 1500 750 365

Percentage of total holding of native and introduced cultivars, breeding lines andreleased varieties

In 1999, Phichit Horticultural Research Centre collected and conserved 47 native cultivars(12.9%), 35 introduced cultivars (9.6%), 275 breeding lines (75.3%) and 8 released varieties(2.2%).

Number of clonal accessions for which botanical seeds are available

After the workshop on sweetpotato in Bogor, Indonesia, in 1996, Phichit HorticulturalResearch Centre conducted research on the collecting and conservation of sweetpotatoby botanical seeds produced by open pollination. Fifty rarely used and floweringaccessions are kept in foil packets in the cold room.

Number of clonal accessions for which passport data are available

Passport data as per the CIP/IPGRI descriptors are available on 47 native cultivars,35 introductions, 275 breeding lines and 8 released accessions.

Number of accessions for which farmers knowledge is available

Eighteen farmer preferred accessions of sweetpotato are collected and conserved atPhichit Horticultural Research Centre. These collections are from ten native sources,viz. Maejo, E-ka, Nigro, Mankaset, MankaiSukhothai, Mantophuck Rayong, Man Chan,Mankaset Nakorn, Khaobaipho and Manphuang, and eight promising accessions, viz.Phichit 1, PIS 115-1, PIS 113-7, PIS 091, PIS 117-5, PIS 94-1, T101 and CIP–14-1.


Number of accessions for which morphological and agronomic characterization dataand further evaluation data are available

After the workshop on sweetpotato at CIP, Bogor, Indonesia, in 1996 and the trainingof sweetpotato scientists at PRCRTC, Philippines, in 1997, Phichit Horticultural ResearchCentre has carried out characterization as per agreed descriptors. All the 47 nativecultivars, 35 introduced cultivars, 275 breeding lines and 8 released varieties have beencharacterized.

Molecular fingerprinting

Molecular fingerprinting of sweetpotato accessions is not done because of budgetlimitations. CIP and IPGRI are encouraged to collect and conserve the importantsweetpotato accessions or released varieties from each country in the ANSWER networkand study molecular fingerprints of them.

Future plans

• Phichit Horticultural Research Centre (PHRC) will continue to collect and conservesweetpotato germplasm by increasing maintenance of botanical seeds and promotingsweetpotato germplasm conservation by farmers in every region of the country.

• PHRC will develop improved sweetpotato cultivars by using the collected sweetpotatogermplasm for fresh consumption and processing and for better sweetpotato.

• PHRC will exchange sweetpotato cultivars among the countries in Asia and Oceania.• CIP and IPGRI should support a budget for the collecting and conservation of

sweetpotato, especially the best, promising or recommended cultivars of each countryfor in vitro propagation and exchange of cultivars among the countries. The countriesin ANSWER may take the interesting sweetpotato cultivars to evaluate in theirlocations.

• CIP and IPGRI should print newsletters about sweetpotato researches from ANSWERcountries or others to assist sweetpotato collection and conservation in the future.

Conclusion

Although sweetpotato is not a staple food of Thailand, it is of local importance as foodand a source of income. Collection and conservation of sweetpotato germplasm arenecessary for breeding to get new varieties with high yield and good quality as requiredby markets, resistance to pests and diseases and early maturity. Sweetpotato conservationin Thailand is of two types: conservation in the field and conservation of botanical seeds.However, the problems of conservation are the lack of funds, high costs and theenvironmental risks. Plot size reduction in field conservation, botanical seedconservation, and the promotion of on-farm sweetpotato conservation make sweetpotatoconservation more efficient. In 1999, research on sweetpotato conservation involved365 accessions of native cultivars, breeding lines and released varieties.

CIP and IPGRI are encouraged to support sweetpotato conservation and to providein vitro back-up storage, especially for good quality sweetpotato accessions from eachcountry and promote exchange of germplasm for the people in Asia and Oceania.

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Fig. 1 Sweetpotato collection in the field genebank at Phichit ResearchHorticultural Research Centre (spacing 1.5x1.5 m)

Fig. 2 Roots of promising cultivar PIS 115-1 that matures in 90 days


Status of Conservation and Use of Sweetpotato Germplasm inVietnam

Luu Ngoc Trinh, Bui Tuyet Mai and Nguyen Ngoc HueGenetic Resources Centre, VASI, Vietnam

Introduction

In Vietnam, sweetpotato takes the third place of importance in the rank of food cropsafter rice and corn. This crop has traditionally been an important food of Vietnamesefarmers and a principal one for those living in coastal areas with prevalence of sandysoils and in midland areas with degraded soils, where there is no cultivation of rice.

In Vietnam sweetpotato is cultivated in the spring crop season in a double cropfarming system characterized by an upland crop in the dry season and summer ricein the wet season. It is well known that North Vietnam has cold winters. Since the early1970s, sweetpotato has extended in North Vietnam as a winter crop in irrigated areas.This is a new cropping season, which has helped to establish a farming system of threecrops per year with rice or an upland crop in spring or spring-summer season, ricein summer or summer-autumn season and an upland crop in autumn-winter or winterseason. Since the establishment of this new cropping system, sweetpotato has beencultivated in the winter season, which requires cold tolerant varieties.

Sweetpotato is an extensive and highly sustainable crop. One can find it cultivatedin any cultivable land, in fields, home gardens, canal borders, etc. in every Vietnamesevillage. Usually poor soils are reserved for sweetpotato cultivation. In intensive farmingsystems, farmers usually practise intercropping of sweetpotatoes with beans, sesame,corn or vegetables. The intercropping system not only increases the total productionin a unit area, but also greatly contributes to soil improvement, and pest and diseasecontrol of the secondary crops. After the main production season of sweetpotato, itsclonal maintenance in home gardens is the means of keeping “clonal seed” for the nextgrowing season.

Sweetpotato has diverse uses. This is an important food source for both people andanimals. As human food, storage roots and young leaves are used. Sweetpotatoes areconsumed fresh or dried for storage over several months. As animal feed, all parts ofthe sweetpotato plant are used. The importance of sweetpotato as food and feed hasdeclined since the early 1990s. This has several reasons: Rice production in Vietnamnow exceeds the country’s self-sufficiency needs. Owing to the rise in the standardof living, the Vietnamese people replace sweetpotatoes in their diet increasingly withrice. The present economic development in Vietnam has led to the intensificationagriculture. Moreover, sweetpotatoes are being replaced by high protein feedconcentrates in the husbandry of pigs and other animals. The current situation ofsweetpotato production in the country calls for a new action plan to prevent geneticerosion and for re-orientating the approach for its genetic conservation.

Activities of conservation of sweetpotato germplasm in Vietnam

Although sweetpotato did not originate in Vietnam, the crop is diverse in this country.This is because of the following reasons:– Sweetpotato has been cultivated in Vietnam for a long time.– Sweetpotato ranks as the third staple food crop in Vietnam and is cultivated widely

all over the country.

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The territory of Vietnam stretches over 15 degrees (from 8°30’N to 23°30’N) and displaysa range of diverse agro-climatic conditions, from the seasonal warm-temperateconditions in the north to the wet tropical conditions in the south.

Collecting and conservation of sweetpotato germplasm in Vietnam were initiatedwith great efforts in the1950s, years after the First Indochina Patriotic War. Almost allgermplasm were lost during the Second Patriotic War (1964–1975). After reunificationof the country, genetic conservation of sweetpotato started again along with thepromotion of conservation and use of plant genetic resources for food and agriculture.The following are the main features of sweetpotato germplasm conservation in Vietnam.

Collecting of germplasm

The collection of Vietnamese sweetpotato germplasm is preserved in the field genebankat the National Crop Genebank under the management of PGRC. Before 1996, thesweetpotato collection was maintained in experimental plots in the field. In 1994, dueto a calamity of inundation, more than one hundred accessions were lost. Since 1995,the collection has been kept in ceramic pots.

Number of conserved accessions:

– Number of accessions collected before 1990 114– Number of accessions collected and introduced during 1990–96 519– Number of accessions collected after 1996 14– Total number of accessions collected 647– Number of accessions actually preserved 524

Composition of collection according to origin:

– Number of local accessions 402 (77%)– Number of introduced accessions 86 (16%)– Number of improved and released varieties 36 (7%)

Number of accessions cultivated in production and used in breedingprogramme:

– 50 varieties (10% of the total) are widely cultivated.– 20 varieties (4% of the total) are frequently used as parents in breeding programmes.

It is estimated that the actual preserved collection represents only half of the totalgenetic diversity of sweetpotato in Vietnam. There are specific remote areas that havenot yet been covered by collecting missions. Further collecting activities need to beconducted to fill geographical gaps.

Characterization and evaluation of germplasm

Much attention has been paid to the issue of characterization and evaluation of cropgermplasm as this is an important part of the strategy of plant genetic resourcesconservation of the NPGR Programme. All the collected or introduced germplasmaccessions have their corresponding passport data. The following are figures oncharacterization and evaluation:– All the varieties have morphological characterization data.– 420 varieties (81% of the total) have evaluation data on agronomic characters,

horizontal pest and disease resistance traits.


Vietnam has no facility for molecular characterization of sweetpotato germplasm,even though this is an important aspect of germplasm characterization and evaluation.PGRC plans to strengthen the Laboratory of Plant Genetic Diversity in the use of newbiological techniques to analyze and study the genetic diversity of crop germplasm.It is hoped that, in the near future, a number of specific varieties of sweetpotatogermplasm can be characterized adequately by molecular techniques.

Characterization of flowering and botanical seed conservation

In Vietnam, sweetpotatoes are seen flowering between October and February, with themajority of accessions flowering between November and December. The following aredata on flowering characterization of the collection:– 246 varieties (50%) flower.– 34 varieties (7%) produce botanical seeds.

Sweetpotato is an hexaploid species. Due to self-incompatibility, it does not setbotanical seeds if it is grown in isolation. When different varieties that flower are growntogether, cross-pollination occurs and heterozygotic botanical seeds are produced. Whensuch seeds are grown, they segregate for many generations, and the true genotype ofthe original maternal variety cannot be re-constituted. Our objective is to conservegenotypes, hence we have no interest in maintaining segregated botanical seeds in thegenebank. The botanical seed of sweetpotato produced by inducing flowering and thenby natural or artificial crossing can be considered as an acceptable way of long-termgenetic conservation of genes, if it is more important than conserving genotypes.However, the possibility of using valuable genes obscured in heterozygotes is still farremoved from the realities of breeding programmes in developing countries.

Identification of duplicate accessions

Sweetpotato being a vegetatively propagated crop has practically no geneticcontamination even if a variety is cultivated for a long time in a particular area. However,as a consequence of a variety being grown for a long time simultaneously in severalplaces, duplicate samples might have been collected. After agromorphologicalcharacterization, the following 18 characters are used to identify duplicates of asweetpotato variety:– Climbing ability – Shoot tip pubescence– Plant type – Colour of leaf veins– Stem diameter – Pedicel length– Stem pigmentation – Pedicel colour– Internode length – Root shape– Leaf shape – Colour of root skin– Leaf size – Thickness of root skin– Mature leaf colour – Colour of root flesh– Immature leaf colour – Form of root-stem connection.

Results show that 223 accessions or 43% of the total are duplicates. The maintenanceof duplicate accessions is not necessary. However, agromorphological characterizationis not enough to confirm putative duplicate accessions as genetically identical. Moleculartechniques are considered as the most advanced methods to ascertain the duplicatestatus of an accession. Duplicate accessions need to be conserved until their positiveidentification.

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Field genebank management

The Vietnamese collection of sweetpotatoes is conserved at the National Crop Genebank.The field genebank was established in 1992 at the Tuber Crop Research Centre. In 1995it was transferred to PGRC, which is responsible to manage the National Crop Genebank.There are two forms of keeping the varieties in the field genebank:– For germplasm maintenance sweetpotato accessions are cultivated in ceramic pots,

35 cm in diameter and 35 cm in height. Two pots are kept per accession. After sixmonths, plants are transferred to pots with new substrate.

– For characterization and evaluation, germplasm is cultivated in experimental plotsin the field. The size of the plots is 1 m x 5 m.

In vitro conservation

In vitro conservation was experimented at the National Crop Genebank in 1993–94. Twoproblems were found:– It was too expensive for conditions of Vietnam in comparison with conservation

in the field genebank. This higher cost is due to the fact that, unlike in developedcountries, in a developing country like Vietnam, chemicals and laboratory facilitiesare expensive while labour is cheap.

From the late 1980s to the early 1990s, much progress has been made in developingand using in vitro techniques, especially at the international agriculture research centres,as a predominant approach for the conservation of vegetatively propagated crops. Afterthat, the actual use of tissue culture in plant genetic conservation has declined. It playsnowadays a limited role even in developed countries. The main problem in developingtissue culture technique as a promising method of plant genetic conservation appearsto be the difficulty of dealing with mutations. The actual strategy of plant geneticconservation of Vietnam considers a role for in vitro conservation in the conservationof difficult material, that is accessions that are seed-sterile or difficult to maintain inthe field.

Plans for the future

As was noted in the introductory section of this paper, excess of rice production andagricultural intensification have reduced the scope of sweetpotato production for bothhuman use and animal feed. The production area of sweetpotato has therefore decreased.In order to adapt to the new production trend, it has been found necessary to reorientthe approach for conservation of sweetpotato genetic resources in Vietnam. The followingare the main activities to be done:• Collecting germplasm in areas previously not covered by collecting missions, thus

filling ecological gaps in collections• Identifying duplicates and studying the issue of their maintenance• Studying and implementing in vitro conservation for accessions that are difficult

to be preserved in the field genebank• Improving the field genebank preservation• Promoting the use of sweetpotato germplasm collection through detailed evaluation,

documentation and propaganda• Promoting linkage of genetic conservation with research development through

diversifying the use of sweetpotato products• Studying and implementing on-farm conservation and conservation through

widening use of germplasm.


Fig. 1 Sweetpotato germplasm in pots at PGRC, VASI in Year 2001

Fig. 2 Sweetpotato germplasm in the field at PGRC, VASI in Year 2001

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Recent Progress in the Conservation and Use of SweetpotatoGermplasm in India

S.K. Naskar1, C.S. Easwari Amma2 and S.G. Nair2

1 Regional Centre of CTCRI, Bhubaneswar-751 019, India; 2Central Tuber Crops Researchinstitute, Trivandrum, India

Introduction

Sweetpotato has its origin in northwestern South America and it was introduced toIndia by the Portuguese during the 16th century. Now, it is an important rootcrop andis grown in almost all parts of the country. In 1997, sweetpotato was grown on an areaof 141 000 ha and had an annual production of 1.174 million tonnes with productivityof 8.326 t/ha (Table 1). The major area of production lies in the east and northeasternparts of the country. The consumption of sweetpotato is high among the rural poor.Farmers in rural areas grow several varieties or mixtures of varieties, which are thebuilding blocks of sweetpotato improvement programme in India.

Table 1. Area production and productivity in IndiaSource: FAO production year book Vol. 51–1997.

Year Area Production Yield1000 ha 1000 mt kg/ha

1989–91 156 1265 81091995 138 1128 81741996 141 1174 83261997 141 1174 8326

Germplasm collecting

Germplasm collecting work has been going on in India since 1963 (Naskar et al. 1996).The Central Tuber Crops Research Institute (CTCRI), Trivandrum, its Regional Centrein Bhubaneswar and the 12 centres under the All India Coordinated Research Project(AICRP) on Tuber Crops Other Than Potato have the responsibility of collectingsweetpotato germplasm from different parts of India. But CTCRI has the mandate forgermplasm collecting and its conservation. Additionally, the National Bureau of PlantGenetic Resources (NBPGR), New Delhi, and its Regional Station in Amravati are alsocollecting and conserving sweetpotato germplasm.

Current status

In India, different institutions maintain a total of 3073 accessions of sweetpotato (Table2). Since the last ANSWER meeting in 1996, 810 accessions have been added tosweetpotato collection. Of these, 798 accessions are maintained by CTCRI. Among theco-ordinating centres, Rajendra Agricultural University (RAU), Bihar and Tamil Nadu,are other centres conserving maximum numbers of collections.

Tables 3 and 4 provide details of the composition of CTCRI’s collection. As seenin these tables, landraces and native cultivars predominate in that collection, followedby introduced materials and breeding lines.


Table 2. Number of sweetpotato germplasm accessions maintained by different organizations/centres in India

Organisation/ Centres Place and StateNo. of Accessions

1998 1996CTCRI Trivandrum, Kerala 847 807RC of CTCRI Bhubaneswar, Orissa 239 253RAU Dholi, Bihar 802 709APAU Rajendra Nagar, Andhra Pradesh 95 85BCKV Kalyani, West Bengal 100 70AAU Jorhat, Assam 29 25KKVP Dapoli, Maharashtra 118 118NEH complex Shillong, Meghalaya 31 31BAU Ranchi, Bihar 94 89NDAU Faizabad, Uttar Pradesh 63 3GAU Navasari, Gujarat 30 NAIGKV Jagadalpur, Madhya Pradesh 85 73TNAU Coimbatore, Tamil Nadu 540 NANBPGR Amravati, Maharashtra NA NA

Table 3. Number of accessions of cultivated and wild Ipomoeaaccessions maintained in CTCRI and its Regional Centre

Type of Germplasm No. of AccessionsCTCRIIndigenous 547Exotic 322Ipomoea species I. aquatica, I. trifida, 5I. triloba, I. setosa, I. batatas var. batata)Regional CentreLandraces 25Breeding materials 146CTCRI accessions 56Ipomoea speciesI. trifida germplasm 80I. triloba 2I. aquatica 1I. nil 1

Table 4. Percentage of holdings of native cultivars, breedinglines and released varieties of CTCRI sweetpotato germplasmcollection

Type of Holding PercentageNative cultivars 43Breeding lines 19Introductions 37Released varieties 1

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Characterisation and documentation

In CTCRI, about 800 accessions have been characterised morphologically (Table 6) and764 accessions have been documented in a computerised database (Rajendran et al. 1992).Passport data are available for 825 accessions. Farmers’ knowledge or indigenousknowledge is known for 371 accessions. Molecular fingerprinting has not been tried.Agronomic evaluation data are available for 200 accessions.

In sweetpotato, about 100 species of pests are known attacking it. Among them thesweetpotato weevil (Cylas formicarius Fab.) is a major pest causing extensive damageand reduction in yield. About 750 accessions in CTCRI and 163 accessions in its RegionalCentre have been screened for weevil infestation. All the accessions screened so farare susceptible to weevil at different levels. At CTCRI, 10% of total accessions screenedare less susceptible to weevil infestation with storage root damage ranging from 2 to21.0%.

A total of 985 accessions in CTCRI and its Regional Centre were screened for theirreaction to different diseases under field condition. Out of 822 accessions screened atCTCRI, 29 were observed to be free of all diseases and the rest were affected by oneor more diseases. Among the virus diseases, chlorotic leaf spot was observed in 498accessions, ring spot in 354 accessions and leaf roll in 73 accessions. Besides, othersymptoms presumably produced by virus like diseases such as puckering was observedin 305 accessions, fan leaf in 49 accessions, internal chlorosis in 26 accessions and yellownetting in 4 accessions (Table 7). Among the fungal diseases, chlorotic leaf distortion(CLD) was observed in 400 accessions and brown leaf spot in 207 accessions (Table7). As biochemical analyses like starch, sugar, carotene, etc. are not completed for theaccessions, update of catalogue has not been done.

Conservation activities

In India, sweetpotato germplasm is maintained in field genebanks (FGB). The germplasmaccessions are replanted thrice in a year (Naskar et al. 1997). Where rainfall is welldistributed throughout the year, sweetpotato is reproduced from vines taken from theprevious crop. Occasionally, sweetpotato is conserved in the form of storage roots keptspread out in the shade, for example, in the Indo-Gangetic Plain.

In vitro conservation is the safest way to conserve germplasm. At present 100 and14 accessions are transferred in vitro in CTCRI and its Regional Centre respectively.Initial establishment of germplasm was done through meristem culture in Murashigeand Skoog (MS) media with 0.1 uM, NAA, 0.1 uM BA and 0.01 uM GA3. The accessionsare then multiplied in MS medium without plant growth regulators. Cultivars areinoculated and incubated at 25–28°C under 8 hours of light (3000 lux). For slow growthmannitol (3%) and sucrose (2%) are effective.

Germplasm utilisation

In India, so far 19 varieties have been released by different organisations. Nine varietieswere released by CTCRI and 10 varieties by different AICRPTC centres (Table 5). Themain breeding objectives in India are development of high yielding varieties withimproved quality along with early maturity and resistance to different biotic and abioticstresses. The regional centre of CTCRI in Bhubaneswar has also developed salt tolerantand drought tolerant lines and the former are being tested in salt affected areas. Effortshave also been made to develop high starch varieties and a few lines have been identifiedfor further testing.


Table 5. Recommended sweetpotato cultivars in IndiaCultivar Yield (t/ha) Skin Colour Flesh Colour Year of ReleaseH-41 20–30 Pink White 1971H-42 20–25 Pink White 1971VL-Sakarkand 20 Purple Light yellow 1974Co-1 20–30 Light pink White 1976Co-2 25–30 Light pink White 1980Co-3 25–30 Light red Orange 1980Rajendra Sakarkand-5 24–30 White White 1985H 268(Varsha) 20–25 Pink Light yellow 1987Sree Nandini 20–25 White White 1987Sree Vardhini 20–25 Pink Orange 1987Samrat 20–28 Dark brown White 1987Rajendra Sakarkand 43 20–25 Brown White 1994Rajendra Sakarkand 35 20–30 Brown White 1994Kiran 22–30 Brown Orange 1994Rajendra Sakarkand 47 25–32 Red White 1997Sree Rethna 20–26 Purple Orange 1997Sree Bhadra 20–27 Pink Cream 1987Gouri 20–25 Purple Deep orange 1998Sankar 14–20 Red White 1998

Table 6. Descriptive information available on the CTCRI germplasmInformation Available No. of AccessionsBotanical seeds 500Passport data 825Farmers IK 371Morphological characterisation 800Molecular finger print NoneEvaluation data agronomy 200Pests (Weevils) 700Diseases 822

Table 7. Germplasm accessions affected by different pests and diseasesPests and Diseases No. of AccessionsPestsWeevil 913Diseases 983No. of disease 29VirusesChlorotic leaf spot 498Ring spot 354Leaf roll 73Virus like diseasesPuckering 305Fan leaf 49Interveinal chlorosis 26Yellow netting 4Fungal diseasesChlorotic leaf distortion (CLD) 400Brown leaf spot 207

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Outlook

India is maintaining more than 3000 accessions of sweetpotato, many of which areduplicates. Therefore, identification of duplicates must be a priority of the futuregermplasm conservation strategy. Though efforts in this regard have been initiated inCTCRI, such work has not been started in other centres. A core collection comprising105 accessions has been identified in CTCRI. Similar work will be taken up in othercentres during the coming years. The duplicate identification would be based onpreliminary grouping using biochemical and morphological descriptors with highreliability. The core collection, duplicate identification in other centres and in vitroconservation and cryopreservation are the future strategies for sweetpotato germplasmconservation. Complementary conservation strategies will include in situ conservationand seed storage.

ReferencesNaskar, S.K, C.S. Easwari Amma and S.G. Nair. 1996. Sweetpotato genetic resources

in India. Pp. 57–80 in Proceedings of a Workshop on the Formation of a Networkfor the Conservation of Sweetpotato Biodiversity in Asia (V. Ramanatha Rao, ed.).Bogor, Indonesia, 1–5 May, 1996. IPGRI APO, Singapore.

Rajendran, P.G., C.S. Easwari Amma and K.R. Lakshmi.1997. Description, documentationand evaluation of sweetpotato germplasm. Central Tuber Crops Research Institute,Sreekariyam, Thiruvananthapuram-695 017.


Appendix 1. Programme

Workshop onAsian Network for Sweetpotato Genetic Resources (ANSWER):Strengthening National Capacity and Regional CollaborationBogor, Indonesia: November 2–5, 1999

November 2, 1999

Arrival of participants

November 3, 1999

08.00–08.30 Registration

Opening and Overview08.30–08.40 Opening: Dr M. Jusuf, (Chairman, ANSWER)08.40–08.50 Welcome: Dr Gordon Prain, (CIP-ESEAP)08.50–09.00 Welcome: Dr V. Ramanatha Rao (IPGRI)09.00–09.30 Overview: Background, major issues and goals of the workshop

– Dr Michael Hermann, (CIP-HQ)

Country Reports(Presentation: 15 minutes; Discussion: 15 minutes)09.30–10.00 Sri Lanka: Mrs P.S.A.D. Prematilake10.00–10.15 Coffee break10.15–10.45 Malaysia: Dr Mohd Said Saad30.30–30.30 Indonesia – National collections- Indonesia and Irian Jaya: Dr M.

Jusuf/Mr Ery Atmojo11.30–12.00 CIP’s Asian Sweetpotato Collection: Mr Tjintokohadi12.00–13.00 Lunch13.00–13.30 Philippines: Prof Algerico Mariscal13.30–14.00 Thailand: Mr Narin Poolperm14.00–14.30 Vietnam: Dr Luu Ngoc Trinh14.30–15.00 India: Dr S.K. Naskar15.00–15.15 Coffee break15.15–15.45 China:Dr Guo Xiaoding15.45–17.00 Discussion and Synthesis19.30 Opening dinner

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November 4, 1999

Project Planning Workshop08.00–08.30 Workshop procedures08.30–10.00 Analysis of persisting problems: Plenary workshop10.00–12.00 Research response to problems: Working group 1/Working group 212.00–13.00 Lunch13.00–15.00 Research response to problems (continued): Working group 1/

Working group 215.00–15.15 Coffee break15.15–17.30 Presentation and discussion by working groups

November 5, 1999

Project Planning Workshop (continued)08.00–10.00 Network organization: Plenary workshop Prioritizing minimal-

funded and fully funded researchWorking group 1Working group 2

13.00–13.30 Lunch13.30–15.30 Presentation of working groups on prioritized research15.30–15.45 Election of coordinator15.45–16.00 Closing ceremony


Dr Guo XiaodingAssistant DirectorXuzhou Institute of Agricultural ScienceXuzhou Sweetpotato Research CentreDonghecun East SuburbsXuzhouJiangsu 221121P.R. ChinaTel : 86-516-3352146Fax: 86-516-3350318E-mail: [email protected]

Dr S.K. NaskarHead, Regional Centre of the CentralTuber Crops Research Institute (CTCRI)Dumduma Housing BoardPO BhubaneswarIndia 751019Tel : 91-674-470528Fax: 91-674-470528E-mail: [email protected]

Dr M. JusufPlant Breeder, Research Institute forLegume and Tuber Crops (RILET)Jl. Raya Kendal PayakPO Box 66MalangIndonesiaTel : 62-0341-801468Fax: 62-0341-801496

62-0341-801075E-mail: [email protected]

Mrs St. A. RahayuningsihPlant Breeder, Research Institute forLegume and Tuber Crops (RILET)Jl. Raya Kendal PayakPO Box 66MalangIndonesiaTel : 62-0341-801468Fax: 62-0341-801496

62-0341-801075E-mail: [email protected]

Mr Ery AtmojoThe Root and Tuber Crops ResearchCentreCendrawasih UniversityJl. Gunung SaljuManokwariIrian JayaIndonesiaTel : 62-0968-214971Fax: 62-0968-211455

Mrs MinantyoriniResearcher, Research Institute for FoodCrop and Biotechnology (RIFCB)Jl. Tentara PelajarBogorIndonesiaTel : 62-0251-338820Fax: 62-0251-338820E-mail: [email protected]

Dr Luu Ngoc TrinhDirector, Genetic Resources CentreVASIVietnamFax: 861-3937E-mail: [email protected]

Prof Algerico MariscalAssociate Professor / Plant BreederPhilippine Rootcrop Research andTraining Centre (PRCRTC)VISCABaybayLeytePhilippines 6521-ATel : 63-53-335-2616Fax: 63-53-335-2616E-mail: [email protected]

Mr Narin PoolpermPlant BreederDepartment of AgriculturePhichit Horticultural Research CentrePhichit 66000ThailandTel : 66-56-612352Fax: 66-56-612351

Appendix 2. List of Participants

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Mrs P.S.A.D. PrematilakeResearch OfficerHorticultural Research and DevelopmentInstitute (HORDI)PO Box 11GannoruwaPeradeniyaSri LankaTel : 94-8-388234Fax: 94-8-388234E-mail: [email protected]

Dr Mohd Said SaadProgramme HeadPlant Genetic Resources CentreInstitute of BioscienceUniversiti Putra Malaysia43400 SerdangMalaysiaTelephone: 6-03-9486101 ext 4077; Fax: 6-03-9423087E-mail: [email protected]

Dr V. Ramanatha RaoRegional Director (Interim) and SeniorScientist (Genetic Diversity/Conservation)International Plant Genetic ResourcesInstitute (IPGRI)Regional Office for Asiathe Pacific and Oceania (APO)P.O. Box 236UPM Post Office43400 SerdangSelangor Darul EhsanMalaysiaTel : 603- 9423891Fax: 603- 9487655E-mail: [email protected]

Dr Michael HermannProject Leader:Conservation & Characterization ofSweetpotato Genetic ResourcesInternational Potato Centre (CIP)Avenida La Universidad 795Apartado Postal 1558Lima 12PeruTel : 51-1-3496017Fax: 51-1-3495638E-mail: [email protected]

Dr Gordon PrainRegional DirectorInternational Potato Centre (CIP)Regional Office for East, Southeast Asiaand the Pacific (ESEAP)Kebun Percobaan MuaraJl. Raya Ciapus, Bogor 16610IndonesiaTel : 62-251-317951

62-251-313687Fax: 62-251-316264E-mail: [email protected]

Mr TjintokohadiResearch AssistantInternational Potato Centre (CIP)Regional Office for East, Southeast Asiaand the Pacific (ESEAP)Kebun Percobaan MuaraJl. Raya Ciapus, Bogor 16610IndonesiaTel : 62-251-317951


Ms Caecilia A. WidyastutiResearch AssistantInternational Potato Centre (CIP)Regional Office for East, Southeast Asiaand the Pacific (ESEAP)Kebun Percobaan MuaraJl. Raya Ciapus, Bogor 16610IndonesiaTel : 62-251-317951


Mr Sukendra MahalayaInformation Management OfficerInternational Potato Centre (CIP)Regional Office for EastSoutheast Asia and the Pacific (ESEAP)Kebun Percobaan MuaraJl. Raya Ciapus, Bogor 16610IndonesiaTel : 62-251-317951



Appendix 3. Summary Tables from Group Discussions

GROUP 1RESULTS OF DISCUSSION

No. Issue Problem Output Action1 Germplasm Geographical gaps Geographical gaps Determine previously

collection in collection filled unexplored areas

Map areas wherefarmers’ varieties areunder threat

Collect in priority areasas well as prioritymaterials (responsibleby country

Erosion of farmers’ Collecting strategyvarieties is not known developedNo strategy forcollectingLack of fund to performthe collecting areas

2 Core Lack of guidelines on Guidelines Compile guidelines fromcollection core sample or core developed the other crops

collectionDetermine corecollection method

How to establish a Core collection Completecore collection established characterization and

documentationIdentify accessionsbased oncharacterization data +geographical + IKinformation, etc.

3 Germplasm Inadequate germplasm Utilization of Evaluate germplasmutilization utilization germplasm (core concerning agronomic,

collection) pest and disease,increased quality

Develop molecularmarkers for efficientselection of quality traitsProvide information ongermplasmIntroduce desiredaccessions

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No. Issue Problem Output Action4 Conservation High cost of in vitro Cost reduction Identify priority

strategy culture strategy developed accessions, thenconserve them in invitro cultureImprove efficiency bydeveloping protocol

High cost of large field Rationalize thecollection collection maintained

Lack of optimum Standardized Undertake researchcryopreservation cryopreservation activities to develop

protocol developed protocolUncertainty about Seed conservation Induce flowering andmethod for seed methodology seed settingconservation developedNeed to perfect the field Field genebank Develop filed genebankgenebank conservation management management system

system developed

Hard to find in situ Methodology to Develop farmerconservation place identify site for in- participatory research

situ conservationdeveloped

Difficulties and safe Cultivars in situ Monitor the movementguarding of cultivars in in safe guarded of cultivars by farmerssitu conservation every season (new

gardens)


GROUP 2MANAGEMENT PROBLEMS

Output ActivityPest and disease free materials Clean all virus infected materials G

Guidelines for pest and disease handling &management

Fully equipped genebank in FGB in less problematic areaenvironmentally friendly environment Share activities that require high cost

Information on germplasm behavior Study relation of environment & character changeList/guide for characters behavior

Trained personnel for genebank BSc as minimum qualificationmanagement Standard training through ANSWER

DATABASE MANAGEMENT

Output ActivityStandard descriptors for duplicate Adopt Huaman + yield, dm, and/or molecular toidentification & management/utilization further Co confirm duplicates

Standard database system Use excel (standard form to be developed)Every member to use the same format and transferdata int to the new system

Centralized database system CIP as the clearing house/manager

PROBLEMATIC ACCESSIONS

Output ActivityUse artificial seed technology Protocol for artificial seed production

Proper field technique Us Use flowering induction methodsPlanting for more than 3 seasons

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