The effect of sowing date and plant density on yield and yield components of safflower (Carthamus tinctorious L.) in Rokh plateau .

To investigate the effect of sowing date and plant density on yield and yield components of safflower ( Carthamus tinctorious) as well as evaluating the possibility of the second sowing of the plant in Torbat Heidariyeh , a field experiment was conducted in Rokh, Cold Season Cereal Research Station 2005 . The experiment was conducted in split plot arrangement in complete randomized block design with four replications . Main plots were sowing date in five levels including 9 April, 10 May, 31 May, 20 June, 11 July and sub plots were plant density in three levels including 300000, 400000, 500000 plants per hectar. Some charactristics such as the number of capitulum per square meter, seed number in capitulum, seed weight, harvest index and seed yeild was evaluated.The highest seed yield was obtained in first sowing date in 3347 kg/ha and a delay in sowing date resulted a decrease in yield. The cold weather in (05/11/2005) caused flower fertility not accured, consequently, sowing was not successful . Results showed that the effect of sowing date on yield depends on the number of capitulum per unit area and the number of grains per capitulum. These two characteristics in th first sowing date in respect of the other dates were higher. The effect of density on yield was significant resulted on yield increase due to capitulum increase in unit area. As a result, the first sowing date with the highest density is recommended. However, The third and fourth sowing date can be considered as the second planting in a sequeational cropping system