Kenya Agricultural Research Institute Mwea Tebere Annual Report

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Kenya Agricultural Research Institute
Cotton plant is a self-pollinated, with about 1 % - 7.5% out crossing depending on intensity of the pollinator. There is a possibility of genetical contamination when varieties are grown in close proximity to one another. Genetic purity of germplasm is therefore maintained on yearly basis to evaluate breeder's seed for centre's varietal trials and hybridization programme. Germplasm from that were recently acquired from the National Genebank of Kenya (NGBK) and 29 others that are maintained at the centre were rejuvenated at Kirogo Farm for further varietal trials and hybridization program. The germplasm were dry-planted at a spacing of 100 x 30 cm at the onset of 2008 short rain season at KARI-Mwea. Hand weeding was done while spraying chemicals were used to control pests. Artificial self pollination (selfing) was undertaken and the seed stored. From the varieties GBK 003056 and GBK 003084 had seedcotton yield of over 4 t ha- I , while the often used germplasm A540, Ca (70) 43 and Vered and three introductions from the NGBK GBK 003042, GBK 003084 and GBK 003047 yielded over 2.8 t ha- I . These are potential alternatives to HART 89M and National Performance Trials (NPT) on these varieties will be carried out in the 2010 crop season.