Syudy of relationships between traits and path analysis in cultivated (Carthamus tinctorius) and wild (Carthamus oxyacanthus) safflower genotypes under normal and water deficit conditions

To investigate the relationship between different traits, discover factors affecting this relationship and to identify components of seed yield in cultivated and wild safflower genotypes, this investigation was conducted at Isfahan University of Technology research farm under two different water regimes during 2008. Significant differences were observed between genotypes belonged to the two species for drought tolerance. Wild genotypes were more tolerant than the cultivated genotypes. In cultivated genotypes under normal moisture condition, number of seed per head, days to flowering, head weight and plant height had a positive correlation with seed yield. Under water deficit condition, seed yield showed non-significant correlation with number of seed per head. Similarly in wild safflowers number of heads per plant and seed weight per head had positive correlation with seed yield under normal condition. Under stress; seed yield was correlated with plant height, number of head per plant and thousand seed weight. Results of step wise regression showed that the kind and order of seed yield components in cultivated safflower was more affected by drought condition. Path analysis indicated that moisture stress changed direct and indirect effects of traits on seed yield. Under normal irrigation regime development of reproductive system (increasing number of head per plant and number of seed per head) directly affect yield, while under deficit irrigation, thousand seed weight was the effective parameter. Results indicated that wild species had high drought tolerance which can be used for breeding of cultivated safflower.