Evaluation of Drought Tolerance Indices in Sunflower Hybrids

In order to find drought tolerance cultivars and determine the appropriate Indices to select drought tolerance in sunflower hybrids, an experimental research was conducted as split plot design based on RCB at the research field of college of Abouraihan of university Tehran in Iran-Pakdasht, in 2009. Irrigation rates were considered in the main plots and sunflower hybrids as sub plots. The result showed that drought tress severely reduced seed weight, seed number per head and grain yield. The Allstar and Azargol hybrids in terms of optimum irrigation with 3448 and 2793 kg.ha-1 and in severe drought conditions Allstar and Hysun 25 hybrids with 829 and 704 kg.ha-1 had the highest grain yield. In order to determine the best indices by their correlation with yield and by exploring biplot and three dimensional graphs in moderate drought conditions GMP and MP indices and in severe drought conditions GMP and STI indices to select the best drought tolerance of sunflower hybrids were detected. Also based on the results of three-dimensional graphs in both moderate and severe drought stress conditions Allstar was the superior to others.