EVALUATION OF CHICKPEA GENOTYPES FOR RESISTANCE TO ASCOCHYTA BLIGHT IN RIFT VALLEY, KENYA

Abstract

In Kenya dry highlands where wheat, maize and barley are main crop, chickpeas are considered as off-season crop (October-February) before the next cropping season providing an alternative source of income to farmers. Chickpea introduction into these areas has not been adopted without abiotic and biotic stresses. Ascochyta blight (AB) a fungal disease is one of the major hindrance causing up to 100% yield loss under favorable climatic conditions. Although the disease can be controlled by use of fungicides, host plant resistance is the cheaper and ecologically sustainable. The objectives of this study were; To screen chickpea genotypes for resistance to Ascochyta blight under controlled environment and field and to assess the extent of variability among chickpea genotypes regarding adaptability to Ascochyta blight in the dry highlands of Kenya. The cultivars were screened in glasshouse in Egerton University and in three sites; University of Eldoret Farm, Koibatek ATC and Egerton University representing the lower highlands & upper midland respectively. Twenty-five genotypes were obtained from Egerton University’s Seed Unit for evaluation in the three sites and in the glasshouse. In the glasshouse genotypes were planted in earthen pots of 7.5×15 cm laid in Complete Randomized Design (CRD) and scored for AB severity 14 days after inoculation. Field experiments were laid in RCBD design with three replications. Data on disease incidence, severity, initial plant stand, days to flowering, days to podding, days to maturity, plant height, spreading, hundred seed weight and grain yield were collected. Data was subjected to analysis of variance using Genstat release 14.0 and means separated using Duncan multiple range test comparison at α ≤ 0.05. Test genotypes showed significant difference (P ≤ 0.001) on resistant levels. Genotypes FLIP 94079C, GENESIS 079, GENESIS 090, GENESIS KALKEE, HOWARD, HOWZAT, ICCV 98801, SONALI, PBA STRIKER, PBA SLASHER, PBA HATTRICK, DOOLIN, THOMAS, LYONS, JIMBOUR, FLIPPER, AMETHYST, KYABRA and LYLE showed resistance YORKER showed moderate resistance and ICCV 00305, ICCV 00108, ICCV 92944, ICCV 95423 and ICCV 97105 showing susceptibility. Genotypes JIMBOUR, YORKER, FLIP 94079C and ICCV98801 were found to be resistant, with stable grain yield and highly adaptable across the environments. Genotypes HOWZAT, THOMAS, SONALI, AMETHYST, DOOLIN, and GENESIS 079 which are resitant but low yielding are recommended for further breeding aimed at improving its grain yields. Genotyping of tolerant genotypes should be done to understand physiology of the expressed tolerance.