Evaluation the effect of low irrigation stress on the quantitative and qualitative yield of promising sunflower cultivars

this research was carried out in order to recognition and evaluate the characteristics related to growth and yield as well as the adaptation of sunflower especially in relation to dehydration conditions.

This research carried as a split plots in a randomized complete block design with three replication and with two factor: irrigation as the main factor and cultivar as sub - factor were performed in the experimental farm of Safiabad Research Center.

Evaluation of means showed, severe irrigation low stress caused a decrease of 19.03, 26.97, 24.34 and 45.08 % respectively in stem height, stem diameter, head diameter and biological yield. Yield and grain yield components of sunflower cultivars also evalouation under the influence of low irrigation stress and the results show a decrease of 45.69, 49.94 and 50 %, respectively in number of grains/head, grain weight/head and grain yield. On the other hand, the percentage of grain oil decreased enough 26.67% under the influence of low irrigation. Oscar cultivar in control treatment with average grain yield of 5.34 t/ha and Shakira cultivar in severe irrigation low stress conditions with average grain yield 2.67 t/ha, respectively produced the highest and lowest grain yield/ha.

despite relative resistance sunflower dehydration stress, maximum grain yield is produced under normal irrigation conditions. Finally, Felix and Labad cultivars according to high grain yield and maintaining yield in conditions of low irrigation stress they are recommended as high yield and compatible cultivars in Dezful region and similar regions.