Document Type : Research Paper
Associate Professor, Department of Plant Production and Genetics, Faculty of Agricultural Sciences and Engineering, Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran.
Ph.D. of Crop Physiology, Department of Plant Production and Genetics, Faculty of Agriculture, University of Maragheh, Maragheh, Iran.
To evaluate the genetic diversity and the effect of drought stress on grain yield of wheat, 56 wheat genotypes were evaluated for drought stress tolerance in field environments in the Kermanshah of Iran during 2010-2011. The experiments were conducted at the Razi University using alpha-lattice design with two replicates under non-stress and drought stress conditions. Several new stress tolerance indices were evaluated. The result of analysis of variance indicated high significant differences among genotypes for grain yield trait. In general, terminal drought stress reduced 27.2% of grain yield. The Shiroudi, Rassoul, Darab-2, Marvdasht, Argh, and Shiraz genotypes which are high reduction of grain yield (61.1, 51.3, 48.4, 44.1, 43.1, and 43.0%, respectively) and also genotypes 318, Ghohar, 330, Mahdavi, and Alamout which are low reduction of grain yield with drought stress (4.1, 4.7, 7.0, 7.5, and 10.2%, respectively). Furthermore, results showed that wheat genotypes can be classified as normal and stress situations using cluster analysis. The correlation analysis among grain yield under non-stress and drought stress conditions with different drought tolerance indices showed that stress tolerance index (STI), yield index (YI), K1STI, and K2STI indices were appropriate indicators to identify the high grain yield genotypes. Based on these indicators, Mughan-1, Golestan, Navid, 330, Darab-2, and Bahar genotypes had the highest grain yield under both experimental conditions. Therefore, these wheat genotypes are suitable for cultivation in Mediterranean regions that are constantly exposed to drought stress at the end of the growing season, and areas with similar climatic conditions.