The Effect of Different Levels of Drought Stress on some Physiological Traits and Chlorophyll Fluorescence of bean Genotypes (Phaseolus Vulgaris L.)

Due to the fact that drought is known as one of the most important factors limiting the growth and production of crops. Identification of tolerant drought stress genotypes is essential. The present study was conducted to evaluate the tolerance of bean genotypes and the effects of different levels of drought stress on some of their physiological traits and their chlorophyll fluorescence to different levels of drought stress. This study was carried out in a factorial experiment using randomized complete block design with drought stress (100%, 75%, 50% and 25% field capacity) in a research greenhouse in university of Tehran. According to the results, applying severe stress caused a decrease in the relative water content of the leaves, but the content of the electrolyte leakage and the leaf temperature of the samples were increased. On the other hand, leaves vegetation, Fm, Fv, Fv/Fm increased with gentle stress compared to control (75% capacity), but severe stresses showed a significant decrease in these traits. Also, F0 increased in severe stresses. The highest leaf vegetation, Fv/Fm, Fm and Fv, as well as the lowest leaf temperature and electrolyte leakage content were related to COS-16 and D81083 genotypes at all levels of stress, respectively. Accordingly, COS-16 and D81083 genotypes were recognized as tolerant and semi-tolerant genotypes for drought stress. Also, the results showed that drought stress had a negative effect on bean genotypes, but the magnitude of these damages was different due to differences in genotypes.