Advances in cassava agronomy research in Uganda in …€¦ · · 2016-03-22Rwebitaba Zonal...

KAWOOYA RONALD Agronomist, NARO

Rwebitaba Zonal Agricultural Research & Development Institute

Advances in cassava agronomy research in Uganda in the last two decades

(1990 – 2010)

World Congress on Root and Tuber Crops Nanning, Guangxi, China, January 18-22, 2016

Content

•  Background

•  Methodology

•  Results

•  Opportunities for cassava agronomy research

•  Projected benefits (intermediate and long term) •  Conclusion

Cassava in Uganda •  Introduced crop in the 1850’s, has rapidly spread in

the different agro-ecologies of Uganda

•  Ranks 2nd (to bananas) in terms of area planted and per capita consumption of 120kg

•  Important as staple food, food security crop & source

of income

•  Area under cassava is about 500,000 Ha. •  Current production is estimated at about 5.4 million

MT

World leading producers of cassava

Objective •  Analyze past & present situation with aim of describing

the lessons learned from past interventions & their implications for a strategy for future investment in cassava agronomy research

Methodology • PARIs were the primary sources of both published & or

unpublished data • Extensive literature search done at Root Crops

Programme at NaCRRI • Other secondary sources included IITA data base with

specific reference to COSCA report • Undocumented data captured through appointments with

retired & serving scientists plus technicians

An account of agronomic research in Uganda, 1990-2010

1) Physiological studies a) Source sink relationships: (Effects of stripping frequency &

time of initiation of defoliation on growth & yield parameters of cassava)

•  Stripping frequency (5, 4, 3, 2 times of defoliation) •  Time of initiation of defoliation (60, 90, 140 and 180 DAP) •  TMS 30786, TMS 30395, Bukalasa 11 and Ebwanateraka •  Results indicated that frequency of defoliation appeared not to

have affected growth significantly until 140 DAP (Max. canopy)

Table 1: Effects of stripping frequency & time of initiation of defoliation on growth & yield parameters of cassava

Stripping Initiation Root Root Leaf Frequency Days after planting number yield yield

0 - 258.1a 8.1a 0

2 225 218.4b 7.2b 10.0

3 180 213.2bc 6.2b 10.9

4 90 212.4c 6.2b 10.9

5 60 203.9c 6.1b 10.4

Values followed by different letters in a column differ significantly (p<0.05)


b) Cyanogenic potential in cassava tubers: (Variation in root yield & cyanogenic potential of cassava roots at different crop growth stages – Yona 1993)

•  3 cassava varieties; Bukalasa 11, Nase 1, and Nase 2

(early, medium and late maturity) were used • Results = Cyanogenic potentials in the root were not

significantly different between 1 and 15 MAP • Cyanogenic potentials were not significantly different

btw 9 & 15 MAP which indicated that plant age at harvest had little effect on the potential tuber toxicity

9 Months CNp (in mg CN eq/kg dry weight) DM (%)

Genotype n Mean Range SD Mean SD TMS 30337 4 178.4 152.9-210.3 25.1 39.8 2.7 TMS 60142 4 131.3 105.5-181.6 35.4 42.6 3.1 Bukalasa 11 4 165.1 124.5-198.5 31.0 41.7 2.4 Variety Mean 3 158.3 131.3-178.4 24.3 41.4 1.4





Table 1: Cyanogenic potential (CNp) and root dry matter content of selected cassava varieties as influenced by harvesting time at Namulonge, Uganda.


An account of agronomic research in Uganda, 1990-2010….

2. Cassava Intercropping System (Biological efficiency of a cassava & maize intercropping system – Yona 1993)

•  4 cassava varieties (TMS 60142, TMS 30572, Bukalasa & Ebwanatereka)

•  Results = Root biomass & Harvest Index were stable indices for indentifying cassava clones for intercropping with maize

•  Competitive Ratio (CR) & Land Equivalent Ratio (LER) were

better measurements of competition levels

•  LER, Area Harvest Equivalent Ratio (AHER) & Competition Ratio for Cassava (CRC) increased consistently with sampling date & were lower under intercropping than sole cropping

An account of agronomic research in Uganda, 1990-2010…..

LER, AHER and CRC of four cassava genotypes intercropped with maize. 1991/92

Months after planting Cassava genotype Parameter 4 6 8 10 TMS 60142 LER 0.36 0.53 0.71 0.69

AHERa 0.36 0.53 0.66 0.54 CRCb 0.05 0.19 0.34 0.33

TMS 30572 LER 0.32 0.34 0.44 0.60 AHER 0.32 0.34 0.32 0.48 CRC 0.07 0.09 0.19 0.35

Bukalasa 11 LER 0.36 0.36 0.53 0.76 AHER 0.36 0.36 0.39 0.62 CRC 0.36 0.06 0.21 0.41 Ebwanateraka LER 0.37 0.51 0.53 0.76 AHER 0.37 0.51 0.38 0.61

CRC 0.06 0.18 0.19 0.38 1992/93 TMS 60142 LER 0.44 0.49 7.74 0.93

AHERa 0.44 0.49 0.63 0.82 CRCb 0.23 0.28 0.55 0.76

TMS 30572 LER 0.56 0.64 0.72 0.01 AHER 0.56 0.64 0.61 0.90 CRC 0.36 0.45 0.53 0.85

Bukalasa 11 LER 0.45 0.52 0.80 0.81 AHER 0.45 0.64 0.71 0.82

CRC 0.36 0.43 0.80 0.95 Ebwanateraka LER 0.62 0.01 0.88 0.90 AHER 0.62 0.01 0.78 0.80

CRC 0.49 0.95 0.80 0.82

An account of agronomic research in Uganda, 1990-2010…..

3. Cassava fertilizer studies (Ways of closing the cassava yield gap from small holder farms in Uganda – Fermont 2004/5).

•  Average yields under farmer management were 8.6 t ha-1 compared to 20.8 t ha-1 yields attained under optimal crop management

•  Poor soil fertility, early water stress & sub-optimal weed management limited cassava production by 6.7, 5.4 & 5.0 t ha-1, respectively

Regime i Farmer

management1

ii + improved crop establishment2

iii +improved genotype3

iv +NPK fertilizer4

SED

Minani - 13.0 (9.0-19.3) 16.4 (9.8-24.5) 25.3 (20.5-31.0) 1.78 Kisiro 8.3 (2.7-12.0) 11.9 (6.4-18.0) 15.1 (6.5-22.8) 23.2 (7.1-35.5) 2.72 Kikooba 11.2 (5.3-17.8) - - - - Chelekuru 11.7 (6.7-17.8) - - - - NaCRRI - 15.5 (11.6-18.9) 21.3 (15.5-27.3) 21.5 (14.8-30.4) 3.13

1Farmer estimates of average cassava yield in their farm; 2Yield of Nase 3 in the 2004 trials with improved crop establishment (1 m x 1 m spacing, no intercrop, timely planting); 3Yield of improved genotype TMSI92/0067 in the 2004 and 2005 trials with improved crop establishment; 4Yield of improved genotype TMSI92/0067 in the 2004 and 2005 trials with improved crop establishment and fertilizer use (100-22-83 N-P-K).

Opportunities for cassava agronomy research in Uganda

Focus areas in cassava agronomy research •  Development of technology packages for cassava & individual

management strategies - (Crop mgt & variety evaluation in major cassava cropping

systems, integrated weed management systems & soil fertility management)

•  Agronomic studies need to be complemented with economic

evaluations and trade-off studies comparing the economic returns for scarce inputs (labour, fertilizer, manure, herbicides) for cassava versus other crops

Projected benefits (intermediate and long term) of cassava agronomy research

•  Weed management options identified and packaged •  Fertility management recommendations for specific cassava cropping

systems •  Patterns and models used to develop nutrient management strategies for

increased cassava production •  Competition models fitted for different cropping systems and agro-

ecologies developed •  Indices and models to guide and accelerate cropping systems based

germplasm improvement generated

Conclusion

q  This review clearly demonstrates that the scope and depth of agronomic research in cassava is limited q  Most studies have limited themselves to a handful of agronomic issues q  Technology packages for cassava & individual management strategies should be tailored towards weed control, drought avoidance strategies & developments of a comprehensive plan for integrated soil fertility management

Acknowledgement

Global Cassava Partnership for the 21st Century

Rwebitaba Zonal Agricultural Research and Development Ins:tute

Thank you

Advances in cassava agronomy research in Uganda in …€¦ · · 2016-03-22Rwebitaba Zonal...

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