Screening of beans (Phaseolus vulgaris L.) genotypes for drought tolerance

Drought is an important factor limiting crop yield and food insecurity globally. Sixty- percent of the bean production areas are prone to drought and subsequently result in eighty-percent of yield reduction. It is emerging as a rising threat to farming communities in Bhutan. Limited studies on crop drought tolerance done in Bhutan. Six bean genotypes (Orey serbu, Orey regtang, Orey brokchilu, Yadhipa orey, Kerongree orey, Brokopali) chose to ascertain drought tolerance. The study was a factorial experiment with Completely Randomized Design (CRD) with six treatments and three replications. Genotypes were subjected to drought stress after 50% flowering till the start of pod formation. The drought condition induced for ten days during the pod formation and the irrigation resumed till harvesting. Means of water-stressed genotypes compared to their corresponding non- stressed with an All-pairwise comparison using the Bonferroni test at the significant level p<.05. The growth (leaf area, relative water content, root length, shoot weight, maturity) and yield parameters (the number of pods, pod length, the number of seeds number per pod, seed weight) determined during the time of harvest. There were significant differences (p<.05) in all the parameters measured under stress and non-stress conditions. Water-stress decreases plant growth and development of all the bean genotypes. With regards to drought susceptibility index (DSI), Orey serbu(1), Orey regtang(1), Yadhipa orey(1), and Kerongree orey(1) had the lowest DSI value. The lesser the susceptible indices, the greater is the tolerance level to the drought and vice versa.