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
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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unpublished data • Extensive literature search done at Root Crops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)
An account of agronomic research in Uganda, 1990-2010
b) Cyanogenic potential in cassava tubers: (Variation in root yield & cyanogenic potential of cassava roots at different crop growth stages – Yona 1993)
• 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
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