Evaluation of Soybean Genotypes (Glycin Max L) to Drought Tolerance at Germination Stage

Drought is one of the limiting factors for better and higher yield of plants. New variety selection is difficult due to the complex mechanism of drought resistance. Soybean is an important legume crop, known for its high quality protein and oil content, which selecting the varieties resistant to drought stress will increase the number of green seedlings and yield. For this purpose, the plants were grown in a completely randomized design with three replications as a factorial with two factors of drought stress and genotype. The genotype factor had 3 levels (Hamilton, M7 and L17) and the drought stress factor had 4 levels (0, -3, -6 and -9 bar). The experiment was done in Laboratory of Agronomy, Faculty of Agriculture Science, Guilan University in 2009 and traits were measured too. Analysis of variance showed that there were significant differences among genotypes for percent of germination. The different levels of drought stress showed significant differences for all studied traits. Genotype×drought interactions were significant for traits germination rate, shoot height and root height. At all levels of drought stress, growth parameters were reduced and the decreasing trend was observed in them but this reduction in the cultivars and traits were different. Out of these three genotypes, M7 genotype showed better response to drought stress in the germination stage and germination index had higher values than the other two genotypes. Here, the sensitive cultivars of all germination indexes were Hamilton. Also, results showed that there is a probability of drought conditions in the germination stage and non use of the stress-sensitive seeds is better and also Seeding quality in stress conditions must be considered.