The Effect of Sowing Dates on Yield, Yield Components and Oil Content of Three Spring Safflower Cultivars (Carthamus tinctorius L.) Under Full Irrigation Regime in Tabriz

To study the effects of sowing dates on seed yield its components and oil content of three spring safflower varieties a factorial experiment based on randomized complete block design with three replications was conducted during the spring of 2009 at Agricultural Research Station, Agriculture Faculty Islamic Azad University, Tabriz branch, Iran. Treatments in this study consisted of four sowing date (26April, 2 May, 8 May, 14 May) and three safflower varieties (Mex33, Isfahan, Goldasht). Analysis of variance showed that late planting(26April) reduced seed yield and oil yield, seed number per head, head number per plant, 1000 kernel weight, planting height, number of leaf, shoot dry weight and oil content of seed. Analysis of variance also revealed that interaction effects of planting date by genotype was significant for height plant. The highest seed yield was observed in the first planting date (2267 kg/ha) and the lowest seed yield at the fourth sowing date (1124 kg/ha). The highest head number per plant was obtained at first planting date (13.44) and the lowest was at the fourth sowing date (6.77).The highest seed number per head was obtained at first planting date (57.78) and the lowest at the forth sowing date (36). The highest 1000 kernel weight at first planting date (37.78gr)and lowest 1000 kernel weight at the fourth sowing date (26.33g).It was also observed that the highest stem height belonged to Isfahan (87.50 cm) at the first planting date and lowest to Goldasht (55.90 cm) at the fourth planting date. The highest oil yield was obtained from first planting date (782.60 kg/ha) and lowest from fourth sowing date (292 kg/ha). However, the effect of sowing date on oil percentages was non significant.