Evaluation and Selection of Sunflower Inbred Lines Under Normal and

Sixty six genotypes of sunflower including cytoplasmic male sterile lines along with their maintainers lines, restorer lines and commercial cultivars were evaluated in tow separate experiments under stress and normal conditions in a randomized block design with three replications in Khoy Agricultural and Natural Resources Research Station in 2004. Stressed experiment was irrigated after 150mm evaporation from class A pan to exert water stress. Each experimental plot consisted of three meter single row with 60cm row spacing and 25cm space between plants. During growing season, plant characteristics including number of days to flowering, growth period duration, plant height, head diameter, 1000 seed weight, seed number per head, oil content, harvest index, seed and oil yield was measured. Stress susceptibility index, stress tolerance index and MP and TOL indices calculated for seed yield. According to the were results, lines A312, A152, B225, CMS19 and R21A with SSI ranged from 0.47 to 0.63 were the highest tolerant lines to water stress. Considering STI, Azargol, line A28 and Alstar with STI 1.06, 0.99 and 0.96, respectively had the highest tolerance to water stress. Because of positive and significant correlation between head diameter, stem diameter and plant height with seed yield and STI, these traits could be used as criteria for determining drought tolerance in sunflower. STI had more efficiency than the other indices for determination of tolerant genotypes