effects of planting date on developmental stages and some agronomic traits of spring safflower varieties

in order to evaluation the effect of planting date on development stages and some characteristics of spring safflower varieties, an experiment was conducted as split plot based on randomized complete block design with six replications at the kabotar abbad research station, isfahan during two growing seasons of 2006-2007 and 2007-2008. three safflower varieties such as arak, sofea and goldasht cultivated at eight planting dates (including 6th march, 20th march, 4th april, 19th april, 5th may, 6th june and 23th june). the results showed that development stages of safflower were longer that it increased vegetative and reproductive growth at the first year of experiment. the highest yield of safflower was observed in the first planting time. by delaying from the first to the 7th planting time decreased photosynthetic areas and seed yield due to enhancing in development. these varieties of safflower were different about some of development. goldasht and sofea were the earliest and latest varieties, respectively. the effect of variety was not significant on seed yield of safflower. the maximum oil content and 1000-seed weight were observed in sofea and goldasht, respectively. goldasht had the minimum plant height.