Evaluation of Soybean (Glycin max L.) Genotypes under Drought Stress using Total Ranking Index (TRI)

In order to study the drought stress in soybean (Glycin max L.), experiments with two stages and 25 soybean genotypes based on Simple Lattice Design 5×5 with two replications in two locations (normal and drought condition) were carried out in Bojnourd. Also evaluation of germination traits with three replications based on Completely Randomized Design has performed. Drought stress was applied in farm after plant establishment at second trifoliate (V2) by irrigation period and in germination experiment, drought stress, has been applied in two levels (normal and -9 bar). Results revealed that among 20 measured traits in field condition, the most reduction in yield components were related to biomass with 32.6% and number of seed per plant with 26.6% respectively. Also drought stress caused a reduction in yield in area by 46.7% and single plant yield by 35.2%. Korona genotype with 69.9% had the highest reduction and Capital genotype with 10.7% had the lowest reduction regarding final yield. Germination assoys showed that plumule with 83.3% and seed length index with 80.44% had the most significant reduction. Considering the Total Ranking Index (TRI), Capital, Chaleston and Jame×Williams genotypes were more resistant to drought stress and Korona and Amuroska were more sensitive to drought stress. Ranking was done by two methods SDI, TRI. Mann Whitney nonparametric test did not show significant differences among genotypes ranking in these two methods.