Investigation of Winter Survival of Safflower Genotypes in Isfahan-Iran

Too often crop production is facing with different intensity of cold damage. In some years the damage is severe and has a large social and economic consequence. Therefore, selection and introduction of cold tolerant cultivars is very effective in reducing cold damage and increasing crop production. Frequently, in winter safflower yield trails in Isfahan province, depending on the intensity of winter cold, different degrees of damage are observed. Cold tolerance study of safflower was conducted in Isfahan province in central Iran during 2007-2008. In this experiment, 20 safflower genotypes were compared in a randomized complete block design with four replications. The effect of genotype on the survival rate, the length of the rosette and ripening period, and their corresponding GDD, plant height, 1000 seed weight, seed yield, and oil content was significant at the 1% probability level. The correlation coefficients between the survival rate with seed yield, length of the rosette period, and corresponding GDD were positive and significant. The correlation coefficient between the survival rates with 1000 seed weight was negative and significant. Covariance analysis showed that Parnian and KW4 had the highest and lowest seed yield with 79 and 7.9% winter survival, respectively. According to the results, genotypes with a longer rosette period such as Parnian,Varamin 295 and Zarghan 279 showed more tolerance to cold damage.