الفهرس 
INTRODUCTION
Effect of drought on sunflower traitsOnly 14 pages are availabe for public view
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Abstract
Objectives: This study is aimed to obtain drought tolerant sunflower genotypes Methods& Results: This study is aimed simultaneously to screen large numbers of sunflower genotypes for all studied traits under normal irrigation and drought stress conditions. Continuously, half diallel crossing among sensitive and tolerant sunflower genotypes has been also investigated to estimate performance of parents and their F1 crosses; to identify the tolerant sunflower genotypes; to estimate phenotypic and genotypic correlations, combining ability, heterosis, nature of gene action and heritability for all studied traits under normal irrigation and drought stress conditions Conclusion: Sunflower genotypes which gave high mean performance for most of the studied traits under both conditions were L230, Sakha 53 and L245 in the first season and the crosses L92 x L245, Giza 102 x L245, and L34 x L245 in the second one and could be classified as drought tolerant sunflower genotypes. The parental sunflower genotypes Sakha 53 and L245 were good combiners for all studied physiological and yield traits; Giza 102 and L34 for all studied earliness traits and L92 for oil percentage. Positive and significant useful heterotic effects over mid and better parents under both irrigation treatments were exhibited by single crosses Giza 102 x Sakha 53, L34 x Sakha 53 and L34 x L245 for all studied physiological, yield and its contributing traits, in addition to negative and significant useful heterotic effects over mid and better parents under both irrigation treatments were showed by single crosses Giza 102 x L34, Giza 102 x Sakha 53 and L34 x Sakha 53 for earliness characters. The dominance gene effects were larger in its magnitude than additive for all studied physiological, earliness, yield and its contributing traits under both irrigation treatments