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\ 3Classification of Sorghum Races in the Southern4Africa Sorghum ~erm pla sm 243A B Obi l snal , K E Pra sada Rao', N M a n g o m b e , and L R House"

Abstracta compaenr o j the charncterizat~on / indzgenour sorghum gennplarm col.lected in Zimbabwe from the 10 countries of the SADC regxon, a total o j 1217accesrionr,from 8 ofthe 10 counmer, lur e ch siji ed for baric and hybnd races.The race ch sif ica t~o n xercise iden t~fied bartc races containing 60 0 accessions,and 10 ~ntem ediate ybnd racer containing 611 occesrionr, and o w i d group(Drummondi!) o f 6 accesslam only Both basic an d hy bn d racer were found to bealmost e q d y prermt in the U D C rcgton'r rorghum grnnplarm

IntroductionCharartenzatton of nermplarm 15 an imponant first stro. after collrction, In the~dentficationand rvaluat;on of indigenous accessions. A slgnlficant component ofcharacterization 1s the clasr~ficat~onf the dlfferent types of accessions contamed ~nthe collect~on.Wlthln the dlfferent types ofsorghum&cesslons In the world, severalforms have been ~den tif ird These were or~einallyclass~fied nto cultivated (31 spe-. .cies) and related wlld rp-clen (17 species) [Snowden 1936, 1955).The vanous groups of sorghum and thelr d~s tnb uti onwere fur ther dercrihed by deWet e t al (1970) It was not until later that a method of classificat~on f the culti.vated sorghums was developed by Harlan and de Wet (1972). They divided thecultivated sorghums (subspecies b~co lor), nto five bas ~c aces: Btcolor (B), Guinea(G). Caudatum (C), Kafir (K) , and Durra (D),nd 10 hybrid races which are com-1 Pr~nclpalScirntar, SADCIICRISAT,PO Box 776. Bulswsyo,Zlmbabwr2 Formcriy S m m Srlrnr8st (Baonl%r),Grnctlc Resovrics Dlnaon. ICRISAT, Paunchem 502 324,hdhra Prndnh.ndm Prnmr addreu Flat 8.4,RKhrcsdn. 31-32.81D a b Gardens.Vm k b p a t n am530 020 Andhra Pndcrh, I d s3 Pht Breeder,Crop Brecdvlg Inmmrr,Dcpmrnmt of Rnurch and Specodat Scruxr,PO Box CY550. C a u w a y , hmr ,Zlmbrbwc4 l7l "02, PO Box 136A.1, Bdcrvdle.NC 28705 USA (formerly Prolcct Mamgo and Exccvtlvr

Dtrcclm,SMXIICRISAT)Ohm.LB.,ud.W, E.M.nmh.N ,a d Houu, LR. 1996 Ch ~ h c n l # o nf rarJlvm rncn

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binations, and really stable intermediate hybrids, of the basic races. These includeGu~n ea-Blcolor GBI. G u~ ne a-C au da twn GC) . Guinea-Kafir IGKI. Guinea-Durra( G D) , ~ a u d a t u m - ~ i c o l o rCB), ~ a f i r - ~ l c b l o r ' i ~ ~ ) ,afir-~a;dat;k (K C) , Kafir-Durra (KD), urra-Bicolor (DB), and Durra-Caudatum (DC). Harlan and de Wet(1972) used ma ture soikelet t v w s for their classification.,Several reasons can be adduced for classifying cultivated sorghums into races. Themost important of these are based on the uses to which the information derived ispu t. These include:- ~dentifica tron of sources of such desirable traits as dlsease, pe st, and d roughtresistance,- Identification of adaotatlon zones:- forms of productlnty and stability among diverse genotypes,- local knowledge and farmer paradigms In sorghum cultiva t~on ; nd- better understanding and use of relationsh~ps mong sp cl e s , and genotypes wlthln

specles, to Improve th e cro p.To achleve the above, and for purposes of conservatlon, ICRISAT, NAR S of the 10countries of SADC, and IPCRI, have coilectrd and assembled 3010 sorehum er rm -plasm accesstons from the reglo; (Mengesha and Appa Rao 1990) O u t o?thesr,-2234are kept at SADC/ICRiSAT SMlP at Matopos, Bulawayo, as a working collect~on.Same of these have been categorized with passport data (Appa Rao and Mushonga1987 ), but not characterized and evaluated In dr t a ~ l

Materials and MethodsA se t of 1217 sorghum accessions, out of the 2234 that constitute sorghum ge rm-plasm from t h e SADC region, were sown, as a germplasm c ha rac teri zat ~onxercise, atAisleby and Muzarabani in the 1988189 and 1992/93 crop seasons (the latter forNa ml b~ an germplasm only). Tw o repllcat~ons were used in each location. T heseaccessions were pan of the total working collection of 12 343 cultivated sorghumgermplasm accessions from all over the world that are being conserved at Matopos.They also represent germplasm from eight SADC countries: Angola, Botswana, Les-oth o. Malaw!, Namibia, Swaziland, Tanz an~a , nd Zim babwe .

Observations were recorded from two-row plots for 13 descriptors as described in'Revised Sorghum Descriptors' (IBPCR and ICRlSAT 1984). However, for the pur-p o x s of this study , only thre e of the descriptors, namely head shape, grain covering,and grain sh ape, were used in classifying th e accessions into race groups.At harvest, tw o head samples per accession were closely observed before threshingfor their shape, the covering of the grain by glumes, and the shape of the grains.Observations were recorded for each accession in each replication at Aisleby andMwnrabnni. The data were processed with simple analysis of variance, and for pri-mary statistical parameters.

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Results and DiscussionTotal numbers and percentages for the different basic and intermedlate hybrid racesof sorghum for each of t he elght SADC countries are shown in Table I. There w ere noobserved vanatlons rn head sha pe , glume covering, and grain shape of t he 1217 germ-plasm access~ons-an indication of the stabil~tyof these three descrtptors with noenvironmental effect on their expression.In the germplasm accesslons classified (Table I), all the five basic races-Bicolor(B), Guinea (C), Caudatum (C), Kafir (K) and Durra (D)-and th e 10 hybridraces-DC, C B, CB , KB,DB, C C , C K , C D , KC, and KD-described earh er hyHarlan and de Wet (1972), were identified, based on their clasr~ficationmethod,using m atu re spike lets, and combined with classes of head and grain shapes.Among the basrc races Culnea was most abundant (276), followed by Kafir (132),Cau datu m (] la ), and D u n a (61). Bicolor was least-abundant wlth only 11 out of the1217 accessions classified. Interestingly, among the ~ntermediate yhrid races, thisleast-abundant baslc race combined in nature wlth one of the abundant races to forma stable natural hybrid, CB (Cauda tum-B icolor). Thls race, with 149 accesslons, wasnext t o th e most abundant intermediate race G C , whlch had 187 accessions. Thethird most abundant of the hybrids was DC w ~ t h 24 accessions. These results are ofsignificance for the relative importance of the races, and thelr combining abilities incrop Improvement. Caudatu m, w ~ t h frequency of only about l0.0%, was recordedas the best natural combiner. It produces. In nature, stable hybrids with three otherraces. C , 8 , and D , and form s the m ost abundant hybrid races In th e region. TheseCaudatum hy br~ d aces occur w ~ t h 5 .4% (GC ). I2 3% (CB), and 10.2% (DC) frr-quencles, relatlvc to the remaining seven races that range from 0.6% (KB) to 3.7%(KD).he Kafir race has the least ability to comblne with other races In nature, asindicated from the relative fr eq ue nc ~e spercentages) of occurrenc e of th e intermedl-ate hybrid races.

A wlld and weedy sorghum group, Drummondil (DR), appeared in the germplasmonly from Angola and N am ~b ta , oth with only six accesslons (0 .5% of th e total). Ittends to be Important in Angola due to its relative frequency of 20.0% in the coun.try's very small germplasm collection. The weedy form might have resulted from acrossing of cultivated and wild sorghum as suggested by de Wet et al. (1970)Table I presents th e stgnificant differences in th e relative frequencies and distribu-tion of sorghum germplasm in southern Afnca. Interestingly, Kafir, which IS absentfrom western Africa and restricted more to eastern and southern Africa (de Wet19 72 ), was fou nd In only five of the eight countries studied. Except for N am ib ~a ,where it is only 2.3%of the accessions, it is fairly abundant in Botswana (17.0%),Lesotho (13.8%), Swavland (28.0%), and Zimbabwe (16.2%).An oth er interesting observ ation in this study is th e appearan ce of Durra in signifi-ca nt propo rtions in Botswana (20.0%) and Namibia (14 7%). This is a new, impor tantfinding. In the description by de Wet et al. (1970), the Durra sorghums were re.s tr ia e d t o western A frica and eastern Africa above latltude 5 ' s . The hndlng ofCaudatum (21.7%) and Duma-Caudatum (20.9%) in Namibian sorghum germplasmis also new t o the distribution presented by de W et et el. (1970), and possibly not

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O C S = R k R E0" m u ," 2 ; FiZ - = i;4 c g l-"?2 =6 C 7 - C z 6" E N = -;' - " " N -N

6 -, , m i ; 6.A= , , , , , , - - - = - 0S 6 i ; - G 3 fm " R g " " ' - 0 N " - " ""- N hl r -- -- 6 s - ? F a RN U -2. = = I I l i m o z n e E N-- R C k f F R R" " R " ";;% - 2 " Z wg 3 s- - - - - -6 k C Ewg - & - = r z , , q 3 s- 2 "3 -u,LD -6 s f q

l-?. " O ' " Z N " ' i; k- - - -- - Y 82 ; gE

- - - r

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hithe no recorded by any other study. W ~ t hhe abundance In Nam~biaof the twohybrid races, C C and DC, ~tcan be hypothesized tha t t he cou ntry could he an area ofnatural hybndizstlon of Caud atum and Duma followed hy the11 d~ ve rs ~f ic at ~o nntoIntermediate hybrid races. This phenomenon could be useful when parents are cho-sen for crop lmprovcment In the SADC reglon, generally, and Namlh~a, pecificallyBicolor IS almost absent from sou the m Africa, except for Angola whe re 30 .0% ofth e accessions are Bicolor types. Thls Is In line w ~ t h he dlstributlon of cultivatedsorghums given by de Wet et al. (1970).Malawi is predominantly a Gu~ne a-sorghum ountry (67% C . 14% C C ). Tanzania(25 W), Ztmhabwe (16.2%), and Botswana (11.0%) follow In the lmportancc ofGulnea in their sorghum ge rmplasm . Frequencies to those In Malaw1 were recordedIn Nigena for Guinea sorghums (Prasada Rao et al. 1985).Figure 1 shows the d~stribution f sorghum races w ~ t hverage ramfall for th e elght

SADC countries studied. From the frequenc~esof sorghum-race dlstr~butlon.~t isobserved that In Tanzania, Malawi, and Angola (countr~esbetween latitudes 2 and17'S, and w t h high average annual ramfall hetwe en 80 9 and 1 320 mm). baslc sor-ghum races were equally or more frequently ohserved than hybrid races. In contrast.In Namib~a,Z ~ mh a h we ,Botswana, Swaziland, and Lesotho (co un tr~ es urt he r away

. . . . . . . ..,.. ., , . , . ,

Tanz Mals Ango Nami Zimb Bots Swar LcsoCountries

Figure 1.Distributionof sorghum nveswith average an nu al rainfall for eight SADCcountries.

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from t h e eq ua tor , betwee n latitudes 17 and 32'S, and with lower average annualrainfall of 50 0-9 00 mm), hyb nd sorghum races were mo re, or as frequently, ob-served as th e basic races.Using th e analysts of pa tte rns of allozyme vanation in wdd and cultivated sorghu m,Aldrich et al. (1992) charactenwd the geographic dlstr~bution f gesletlc diversity Inbo th sorghum types. T heir analysis showed tha t levels of genetic diversity are greaterin wild sorghu m than in cultivated sorghum , although variability w ~ th in he culttvatedsorghum s was mo re than in wild sorghum s, according to de We t e t al. (1970). In usingallozyme analysis for crop Imp rovem ent, it would be necessary to study th e corres-pondence between Guinea and Caudatum of southern Afrlca and those of westernAfrica. The expected results would facilitate sorghum breeders to capitalize on ge-netic diversity and variablllty across t h e tw o regions.

ReferencesAldrich, P.R., Do ebley, J., Sch ertz, K.F., and Stee , A. 1992. Pattern5 of allozymevanation In cultivated and wild Sorghum bicolor. Theoretical and Applied Genetlcs85:451-460.Appa Rao, S., and Mushonga, J.N. 1987. A catalogue of passport and charactenza-tion data of sorghum, pearl mlllet and finger millet germplasm from Z~mbabwe.Rome, Italy: International Board for Plant Genetic Resources (now IPGRI). 74 pp.d e W et, J.M.J., Harlan , J.R ., and Price, E.G. 1970. Ongin of varlabil~ty n theSpmraneo complex of Sorghum bicolor. American Journal of Botany 57(6):704-707.Harlan , J.R., a nd d e Wet, J.M.J. 1972. A simplified classification of cultivated sor-ghum. Cr op Science 12(2):172-176.IBPGR an d ICRISAT. 1984. Revised sorghum de scriptors Rome, Italy: lnter na t~o na lBoard for Plant G en eti c Resources (now IPGRI) 36 pp.Mengesha, M.H., and App a Rao, S. 19 90 . Germ plasm from SADC countries main-tamed at ICRISAT, India, and ns implicattons on national programs. Pages 31-46 inProceedings of the S ~ a h eg~onalWorkshop on Sorghum and Millets ImprovementProgram , 18-22 Sep 1 989, Bulawayo, Zimbabwe Bulawayo, Zimbabwe:SADC/ICRISAT.Prasada Rno, K.E., Obilana, AT., and Mengesha, M.H . 1985. Collect~o n f Kaura,Fara-Fara and Gu ine en se sorghum s in northern Nigena. Journal d'Ag riculture Tradl-tionelle et d e Botantq ue AppliquCe. 32:74-81.Snowden, J.D. 93 6. Cultivated races of sorghum . London, UK : Adlard and Sons.274 pp.Snowden, J.D. 1955. T he wild fo dder sorghum s of th e section Eu-sorghum. JournalLinnean Society, Botany (London) 55:191-260.