This study was conducted to investigate the dwarfness and earliness traits and the possibility of transferring these traits from dwarf plants with low yield to tall plants with high yield and also to evaluate the effects of drought stress on intra-specific hybrid plants.The plant materials were included C4110, PI537652 and A82 parental genotypes and the F 2 progenies of an intra-specific hybridization between parental genotypes.The experiment was carried out as a randomized complete block design with three replications with 2 levels of irrigation-water amount included non stress( irrigation after 80 mm cumulative evaporation from /plant, the number of primary branches and 100-seed weight. Mean comparisons of genetic groups at non stress condition showed that there were significant difference between the genetic groups and the higher values for all traits were observed on tall group. At drought stress conditions, the same result was observed except for 100-seed weight and higher values for all traits were observed on tall group.Mean comparisons between two genetic groups at stress and non stress conditions showed that in tall genetic group except for days to stem elongation, head/plant and the number of primary branches, the other traits had higher values at non stress condition than the stress condition. Also in dwarf genetic group, except for days to stem elongation, 100-seed weight and height, non stress condition had higher mean values than stress condition. Analysis of regression for height on earliness traits could separate early and late maturing and tall and dwarf groups. The results showed that dwarf and tall plants are early and late maturing respectively. The results of genetic analysis including chi-square test and genetic variance showed that only one single gene was effective on the control of height and earliness showed by A and B alleles( dominant genes) and a and b alleles( recessive genes) for height and earliness, respectively. Key words : safflower, intraspecific hybridization, height, earliness. .
