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

Transcription

1 Advances in cassava agronomy research in Uganda in the last two decades ( ) KAWOOYA RONALD Agronomist, NARO Rwebitaba Zonal Agricultural Research & Development Institute World Congress on Root and Tuber Crops Nanning, Guangxi, China, January 18-22, 2016

2 Content Background Methodology Results Opportunities for cassava agronomy research Projected benefits (intermediate and long term) Conclusion

3 Cassava in Uganda Introduced crop in the 1850 s, has rapidly spread in the different agro-ecologies of Uganda Ranks 2 nd (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

4 World leading producers of cassava

5 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for future investment in cassava agronomy research Methodology PARIs were the primary sources of both published & or unpublished data Extensive literature search done at Root Crops Programme at NaCRRI Other secondary sources included IITA data base with specific reference to COSCA report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

6 An account of agronomic research in Uganda, ) 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 a 8.1a b 7.2b bc 6.2b c 6.2b c 6.1b 10.4 Values followed by different letters in a column differ significantly (p<0.05)

7 An account of agronomic research in Uganda, 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

8 An account of agronomic research in Uganda, Table 1: Cyanogenic potential (CNp) and root dry matter content of selected cassava varieties as influenced by harvesting time at Namulonge, Uganda. 9 Months CNp (in mg CN eq/kg dry weight) DM (%) Genotype n Mean Range SD Mean SD TMS TMS Bukalasa Variety Mean Months CNp (in mg CN eq/kg dry weight) DM (%) Genotype n Mean Range SD Mean SD TMS TMS Bukalasa Variety Mean Months CNp (in mg CN eq/kg dry weight) DM (%) Genotype n Mean Range SD Mean SD TMS TMS Bukalasa Variety Mean

9 An account of agronomic research in Uganda, 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

10 An account of agronomic research in Uganda, LER, AHER and CRC of four cassava genotypes intercropped with maize. 1991/92 Months after planting Cassava genotype Parameter TMS LER AHER a CRC b TMS LER AHER CRC Bukalasa 11 LER AHER CRC Ebwanateraka LER AHER CRC /93 TMS LER AHER a CRC b TMS LER AHER CRC Bukalasa 11 LER AHER CRC Ebwanateraka LER AHER CRC

11 An account of agronomic research in Uganda, 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 management 1 ii + improved crop establishment 2 iii +improved genotype 3 iv +NPK fertilizer 4 Minani ( ) 16.4 ( ) 25.3 ( ) 1.78 Kisiro 8.3 ( ) 11.9 ( ) 15.1 ( ) 23.2 ( ) 2.72 Kikooba 11.2 ( ) Chelekuru 11.7 ( ) NaCRRI ( ) 21.3 ( ) 21.5 ( ) Farmer estimates of average cassava yield in their farm; 2 Yield of Nase 3 in the 2004 trials with improved crop establishment (1 m x 1 m spacing, no intercrop, timely planting); 3 Yield of improved genotype TMSI92/0067 in the 2004 and 2005 trials with improved crop establishment; 4 Yield of improved genotype TMSI92/0067 in the 2004 and 2005 trials with improved crop establishment and fertilizer use ( N-P-K). SED

12 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

13 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 agroecologies developed Indices and models to guide and accelerate cropping systems based germplasm improvement generated

14 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

15 Acknowledgement Global Cassava Partnership for the 21 st Century Rwebitaba Zonal Agricultural Research and Development Ins:tute

16 Thank you