تعيين شاخص هاي مناسب تحمل به خشكي براي گزينش ژنوتيپ هاي سويا

Determination of Suitable Drought Tolerance Indices for Selection of Soybean Genotypes

Water deficit is the prime limiting factor in soybean production in semi-arid regions. Therefore, increasing soybean seed yield in Iran requires selection of resistant and adapted cultivars to dry or water deficit conditions. In this investigation, the effect of drought stress on traits, determination of the suitable drought resistance indices and detection of the drought tolerant soybean genotypes were studied in a factorial experiment in a randomized complete block design arrangement with three replications. The factors under study were seven soybean genotypes and three levels of drought stresses (control, 50% and 30% available water). Six drought resistance indices, such as MP, GMP, TOL, SSI, STI and HARM were assessed on the basis of seed yield under both stress and non-stress conditions. Stress intensity for drought level of 50% was low (SI=0.261) while for 30% level was high (SI=0.516). Based on the results of correlation between drought resistance indices and seed yield in stress (S50% and S30%), and non-water stress environments, indices of MP, GMP, HARM, STI because of their high correlations with seed yield in both environments were found to be the suitable indices. According to the bi-plot graph, cultivar Williams at S50% and S30% levels of drought was recognized as the most tolerant cultivar to drought stress.