Evaluation of Bread Wheat Germplasm and Identification of Water Deficit Tolerant Genotypes in Rain-Fed Conditions of Zanjan Region

In order to evaluate the tolerance to water deficit stress in bread wheat genotypes, 144 genotypes in square lattice with two replications and in two modes of supplementary and water deficit irrigation were evaluated in the rainfed research station of Zanjan Agricultural Research Center during the 2016-2017 crop year. Based on grain yield under supplementary and water deficit irrigation conditions, different stress tolerance indices were measured. The results of analysis of variance showed the existence of genetic diversity between the studied genotypes based on water stress tolerance indices. Comparison of mean genotypes in terms of yield in supplementary and water deficit irrigation conditions showed that 82, 101, 116, 13, 86, 131 and 65 have the highest yield in both environmental conditions. Based on STI, MP, GMP and HM indices, G88 and based on TOL, SSI and YSI indices, G41 genotype were identified as tolerant genotypes. Apart from SSI and YSI indices, other studied indices had a significant correlation with environmental performance and therefore can be used effectively to select cultivars tolerant to drought stress. Using bi-plot diagrams obtained from analysis to the main components, genotype tolerance indices were divided into two separate groups. The genotypes identified by STI, MP, GMP and HM indices were grouped and the genotypes identified by TOL, SSI and YSI indices were placed in a separate group. The genotypes identified in this study can be used in future breeding programs of bread wheat to tolerate water deficit stress in the region.