Evaluation of relation of grain yield with important agronomic traits of white bean (Phaseolus vulgaris L.) using different analyses methods under normal and water stress conditions

To study the phenotypic and genotypic diversity of some important agronomic traits associated with yield in white beans, 30 genotypes of white bean were evaluated using a randomized complete block design with four replications in two environments under water stress and non stress conditions. Analysis of variance for most of the traits showed significant differences among genotypes, indicating the existence of genetic variation among varieties. Most traits were affected by the stress. The results indicated that grain yield, weight of pod, biological yield, number of grain per plant and number of pod per plant in white bean reduced under water stress condition whereas, evaluation of drought resistance in bean genotypes, showed that stress tolerance index (STI) and mean productivity (MP) and geometric mean productivity (GMP) were the best criteria for recognizing tolerant genotypes (21 and 30). Under both condition weight of pod was highly correlated with the grain yield. Factor analysis was performed for genotypes both under water stress and non stress conditions and under both conditions three common factor have been extracted, which described most of traits variations. Stepwise regression analysis showed that in water stress conditions, pod weight, harvest index, 100 grain weight and number of grain per plant and in non stress conditions pod weight, harvest index and biological yield have the highest effect on grain yield. Result of path analysis showed that the highest direct positive effect was related to weight of pod under both condition. In classification of genotypes based on phenotypic characteristics, using cluster analysis (UPGMA), all genotypes classification into three separate groups under non stress and stress condition.