Evaluation of Advanced Common Bean (Phaseolus vulgaris L.) Breeding Lines for Multiple Disease Resistance and Yield in Western Kenya

Common bean (Phaseolus vulgaris L.) is one of the most important legume crops in the world, grown for economical and nutritional value. However, its productivity is constrained by diseases such as angular leaf spot, anthracnose, common bacterial blight, halo blight and bean scab. Under favourable conditions, yield losses of between 50 -100 percent have been reported in susceptible cultivars. Identifying and using resistant common bean genotypes with broad resistance is the best economical and sustainable option to reduce the impact of such diseases. So far, no cultivars have been identified with desirable agronomic traits possessing multiple disease resistance (MDR) to these diseases for adoption by dry bean farmers in western Kenya. Field experiments were carried out to evaluate thirty-six advanced dry bean breeding lines for their resistance to major diseases and agronomic performances. The experiment was laid using 6 x 6 lattice design replicated 3 times during the long rain cropping season of 2020. Data on disease severity and agronomic traits were recorded and subjected to analysis using SAS statistical software. Major diseases observed in the field included Angular leafspot, anthracnose, bean scab, common bacterial blight and halo blight. Analysis of variance indicated significant (p < 0.05) variations existed among the genotypes for yield and disease resilience. Nine genotypes (CAL 110, CAL 97, RWR 2245, CAL 232A, CAL 51, CAL 70, CAL 94A, CAL 273 and CAL 257) were identified to possess anthracnose, ALS, CBB, halo blight and scab resistance. Among these, genotypes CAL 70, CAL 110, CAL 51, CAL 232A, RWR 2245 and CAL 257 executed well for grain yield. The identified genotypes possessing multiple disease resistance and with good yield potential stand out as potential candidates for release to farmers in the target area and other similar agro-ecologies in Kenya even though further evaluations on farmers’ fields are recommended. Key words: Phaseolus vulgaris L., elite germplasm, disease resilience, agronomic performance, yield