Identification of Drought Resistant Genotypes in Sunflower (Helianthus annus L.)

To evaluate some agronomic and physiological characteristics under drought stress, determining the best quantitative indices for drought resistance, and identifying drought resistant sunflower genotypes, a field experiment with 36 sunflower genotypes was carried out in 2008-2009 at the research farm of Dryland Agricultural Research Institute (Sararood), Kermanshah, Iran. Thirty six genotypes of sunflower were evaluated in a 6 ´ 6 lattice design with two replications under normal and drought stress at flowering and seed development stages. Some agronomic and physiological characteristics under drought stress and seed yield under both conditions were measured during the growing season. The results of analysis of variance showed that differences among the genotypes for plant height, relative ionic leakage and cell membrane stability traits were significant at the 1% and for seed yield at the 5% probability levels. Drought tolerance indices MP, GMP, HarM and STI exhibited a high correlation with seed yield in both stress and non-stress conditions and were recognized as the best indices for selecting genotypes with high yield potential and resistant to drought stress. Using biplot method, SIL-237, SIL-218, SIL-210, SIL-206, SIL-240, SIL-140, SIL-42, SIL-96, SIL-238 and SIL-227were recognized as resistant genotypes. Genotypes that produced higher seed yield and were drought resistant can be used to develop resistant hybrids.