Study the effect of drought stress on agronomy traits of new sunflower hybrids

In order to study of drought stress effects on yield and it,s components also determine drought tolerant and high sunflower hybrids 3 experiment was carried out in with replications using randomized complete block design in Islam Abad station in 2011-2012. Levels of drought stress including moderate stress and high stress was arranged in main plots and new hybrids of sunflower consisting of Farrokh, Shf81-90, Ghasem and Barzegar was arranged in sub plots. Results of combined variance analysis showed effect of drought stress had significant effect on all of traits consisting number of leaf, days to reproductive phase, beginning of flowering, complete of flowering, end of flowering, physiological ripening, filling period, head diameter, seed per head, plant height, seed yield, biological yield and harvest index at 1% level. Effect of genotype was statistically significant for all traits expect number of leaf at 1%. Interaction effect between drought stress and Genotypes was statistically significant for number of leaf, days to complete flowering, physiological ripening, filling period, plant height, head diameter, seed weight, biological yield and harvest index at 1% level and for grain yield at 5% level. Mean comparison of data by Duncan showed that days to maturity for full irrigation and severe drought stress conditions was different and with 102 and 98 were located in class A and C, respectively. Days to maturity for Barzegar and Farrokh was 105 and 96, respectively. Mean of hybrids yield under full irrigation and severe drought stress conditions were 4192 and 2570 kg/ha, respectively. seed yield under drought stress with 2570 kg/ha was the least and located in class C. Mean comparison of hybrids by Duncan showed that barzegar and ghasem with 4087 and 2500 kg/ha were located in class A and C, respectively. Results showed that barzegar and ghasem had the highest and lowest seed yield under full irrigation with 5007 and 3283 kg/ha, respectively. Under severe drought stress, barzegar had the highest seed yield with 3072 kg/ha.