Evaluation of Drought Tolerance Indices in Soybeans

Forty selected soybean (Glycine max L. Merr) in the form of a randomized complete block design with three replications under normal irrigation and stress conditions in two separate locations, in the research farm of Karaj Seedling and Seed Breeding Research Institute in 2015-2015 crop year Was examined.Based on performance under non-stress (Yp) and stress (Ys) conditions, quantitative indices of drought tolerance, tolerance index (TOL), geometric mean (GMP), stress tolerance (STI), stress sensitivity (SSI), dry sensitivity (SDI), stress sensitivity percentage (SSPI), harmonic mean (HARM), stability Yield (YSI), relative dryness (RDI), were calculated. The results of analysis of variance showed a significant difference in genotypes in terms of yield per hectare under normal conditions at 5% probability level and a significant difference at 1% probability level of genotypes under water stress conditions. The results of mean comparison showed that the highest mean yield in irrigated and rainfed conditions belonged to 19 and 34 genotypes, respectively. The lowest values ​​of tolerance index, stress sensitivity, stress sensitivity percentage, drought sensitivity, belong to cultivars 7, 10, 7, 10, respectively, and the highest values ​​of geometric mean index, stress tolerance, performance stability, relative drought, harmonic mean, Belonged to the numbers 1,7,7,7,1, respectively. Correlation analysis of yield and drought tolerance indices in stress and non-stress environment showed that STI and GMP indices are the most suitable indices for selection top genotypes. Factor analysis also showed that the first two factors explain 98% (the first factor of 58.9% and the second factor of 39.3%) of the studied changes in stress and non-stress conditions. Based on biplot analysis based on the first and second main components, genotypes 1 and 34 are located in the region with high production potential and low sensitivity to stress, and biplot analysis justifies the selection of stress tolerant genotype based on GMP.STI ​​index.