كليدواژه :
شاخص تحمل , رويشي , تنش خشكي , زايشي،سويا
چكيده لاتين :
To study the effects of water deficit stress at different growth stages of soybean, 20 cultivars and lines of soybean were evaluated in a randomized complete block design of three replications in three environments of: non-stressed, water deficit stress of the reproductive stage (R), and water deficit stress at the vegetative and reproductive stages (V+R), at the research farm of Seed and Plant Improvement Institute (SPII) in 2002-2003. Morphological and phenological traits were evaluated during the study. Interaction between stress and cultivars was significant for such traits as plant height, node number, plant weight, as well as 100 seed weight. Means comparison of water deficit levels showed that water deficit stress in the vegetative and reproductive phases caused decrease in plant height, number of pods, number of branches, seed number, pod weight and 100 seed weight. Yield and harvest index were reduced as a result of water deficit stress. The only trait which increased as a result of drought stress was the seed protein percentage. Stress indices for genotypes were also evaluated in water deficit conditions. GMP and STI were found as better indicators than the others. The results of ranking as based on either index were found out to be the same. Under stress in reproductive stage, M4 , M12 and M]0 were more tolerant, while under stress in vegetative and reproductive stage, M4, Williams and Wisconsin were shown to be more stress tolerant than the other lines and cultivars.
