Path analysis of the relationships between grain yield and some morphological characters in spring safflower (Carthamus tinctorius) under normal irrigation and drought stress condition

Abstract

Safflower seeds is a nutritional addition to poultry feed. Historically, safflower (Carthamus tinctorius L.) was used for medicinal and culinary purposes. Today, safflower is grown commercially for its seed oil, homemade dyes and birdseed or animal feed mixes. The association among yield components and their direct and indirect influence on grain yield of safflower were investigated in two conditions. In this purpose, thirty spring safflower genotypes were tested via the randomized complete block design with three replications in normalirrigation and drought stress conditions in the research station of Faculty of Agriculture, Islamic Azad Shabestar University in 2009. The phenotypic correlation among the traits and their path coefficient were estimated in both condition. Positive and significant correlations were observed between grain yield and days to maturity, number of seeds per head, plant height, plant weight, hectoliter weight, biological yield and oil yield. Positive direct effects were exhibited for plant height, 100 seed weight, plant weight, hectoliter weight on grain yield under irrigated conditions. In case of drought stress conditions, grain yield was positively and significantly correlated with number of seeds per head, effective head weight, plant weight, harvest index and oil yield. Positive direct effects were observed for number of seeds per head, 100 seed weight, days to 50% flowering on grain yield and negative direct effect was observed for days to maturity on grain yield under drought stress conditions. Therefore, improvement of the grain yield will immensely be efficient via 100-seed weight based selection in both conditions. Also direct selection could be made for plant height, plant weight and hectoliter weight for the improvement of grain yield under irrigated conditions. Under drought stress conditions selection could be made for number of seeds per head, 50% days to flowering. Key words: Drought stress, grain yield, path analysis, phenotypic correlation, safflower, yield components.