Effects of planting date on yield and yield components of spring safflower cultivars in Markazi province

In order to evalute the effects of planting date on yield and yield components of spring safflower cultivars, this study was carried out in Arak, Iran, in year 2000. A split-plot arrangment of treatment in a randomized complete block design with four replications was used. Planting date were assigned in the main plots and cultivars were arranged in the subplots. Seed were sown by hand (whitout preplanting irrigation) on April 24, May 9 and May 24, 2000. Five cultivars of spring safflower including Gila, UC - 1, Nebraska - 10, Arak -2811 and Esfahan local cultivar were used. Each subplot consisted of 4 rows, 7 m long with 50 cm between rows and 5 cm between plants on the rows. In this study, grain yield and it's related characteristics such as: date of emergence, plant height, branching height, number of branches, number of bolls per plant, number of infertile bolls per plant, number of seed per boll, 1000 seed weight, biological yield, seed oil percentage, oil yield and harvest index were assessed. Results indicated that Arak - 2811 and Esfahan local cultivars were significantly superior to the other cultivars. Considering the earliness of Gila cultivar, it could be included in a crop rotation after barley without concern of unsuitable weather of autumn, and an acceptable grain yield could be harvested.