Evalution of sunflower varieties for yield production under drought stress conditions using statistical tolerance indiceseces. Applying of different stress evaluation indices for studying sunflower cultivars yield in drought condition

Effects of In drought stress were examined in three sunflower cultivars for the order to evaluate water stress on yield of three yield production. A split plot sunflower cultivars an experiment based on a randomized complete block desighn with three replications was conducted in a RCBd based split plot with three replicates in the aAgriculturl rRResearch Station of Islamic Azad University, IAU Tabriz Branch. branch. Five drought tolerance evaluation indices including MP (Mean Productivity), GMP (Geometric Mean Productivity), TOL (Stress Tolerance), STI (Stress Tolerance Index) and SSI (Stress Susceptibility) were estimated for each varietycalculated. The rResults showed that significant threre were ddifferences between three among cultivarُ s for the yield. The variety named Armavirsky with produced the highest yield (586 kg/ha) per hectar in non-stess produced highest yield in contorol condition as compared to other varieties but v (without stress). ariety Euroflour cultivar produced (67 kg/ha) the highest yield in stress with 67 kg per hectar produced higher grain yield under stress condition (67 kg/ha) in comparsion with the two others. cultivars. The hHighest amount of STI was estimeted for belonged to Armavirsky with a value of 0. 57. Based onConsidering the GMP index, variety Armavirsky was also a high tolerant toleerantce cultivar (586 kg/heha). However, based according toon SSI and TOL indicesexes, Euroflour was more tolerantstand at the top as a toleranttolerance cultivar, whereas variety and Armavirsky still showed higher value of tolerance by MP. Correlation analysis between Ys and Yp with other stress indices showed revealed that there was no relation between Ys and other tolerance indices but Yp has higher correlatedion with STI, TOL, GMP and MP. It is concluded that variety Euroflour can be recommended in stress and variety Armavirsky in non-stress conditions. Indeed, indicesIndeces such as and MP. GMP, STI and MP was are reliable suitable for selecting stable genotypes with high potential productivity. yield stability evaluation and selecting high yield cultivars.