Differences in antioxidant, morphological and biochemical responses to drought stress in different cultivars of common bean (Phaseolus vulgaris L.)

Drought stress is the most common environmental stress that can significantly influence crop productivity. In this study, morphological and biochemical properties of 17 genotypes of common bean were evaluated under different levels of drought stress and the most sensitive and tolerant genotypes were identified using multivariate analysis. The results indicated that morphological and biochemical characteristics of common bean were significantly influenced by drought stress, genotype, and genotypes ×drought stress interaction. Principal component analysis summarized the 14 indices to four components which explained 85.71%, 84.52%, 85.86% and 84.94% of the total variation at control, moderate, severe and combined data, respectively. The correlation coefficients among most of the quantitative traits were statistically significant at all drought stress levels. A significant and positive correlation between chlorophyll and carotenoids with ascorbate peroxidase activity was observed at both moderate and severe drought stress conditions. These associations suggest that this enzyme plays an important role in ROS scavenging under drought stress. Clustering analysis grouped the genotypes into four divergent groups. The genotype-by-trait biplot analysis indicated that genotypes 1 and 2 were the most drought-tolerant and genotypes 12 and 16 were the most drought-sensitive genotypes under both moderate and severe drought stress conditions.