Cold tolerance of safflower genotypes in field conditions

To reduce cold damage in the cold and semi cold region in country, study and introduction of cold tolerant varieties is very important. In yield trials of winter safflower in Kabootar-Abad Agricultural Research Station different rates of cold damage on plants were observed. Therefore, study of cold tolerance of safflower genotypes was conducted in ۲۰۰۷-۲۰۰۸ at the Kabootar-Abad Research Station of Isfahan. In this experiment twenty safflower genotypes were planted in October ۲۰th using a complete block design with four replications. Genotype effect was significant on frost – bite percentage, No. of frost - bitten plants, period of rosette and ripening and corresponding GDD’s, plant height,۱۰۰۰ kernel weight, seed yield and oil percentage. Gol-Sefied Isfahan and kw۴ were the most tolerant and sensitive genotypes to winter cold and had the highest and lowest seed yield, respectively. Genotypes that had more tolerance to winter cold had longer rosette period and correlation between them was negative and highly significant. Sensitive genotypes to winter cold because of lower density produced larger seed and the correlation between seed size and frost-bite percentage was positive and highly significant. Correlation coefficients among frost–bite percentage and plant height and oil percent were not significant.To reduce cold damage in the cold and semi cold region in country, study and introduction of cold tolerant varieties is very important. In yield trials of winter safflower in Kabootar-Abad Agricultural Research Station different rates of cold damage on plants were observed. Therefore, study of cold tolerance of safflower genotypes was conducted in ۲۰۰۷-۲۰۰۸ at the Kabootar-Abad Research Station of Isfahan. In this experiment twenty safflower genotypes were planted in October ۲۰th using a complete block design with four replications. Genotype effect was significant on frost – bite percentage, No. of frost - bitten plants, period of rosette and ripening and corresponding GDD’s, plant height,۱۰۰۰ kernel weight, seed yield and oil percentage. Gol-Sefied Isfahan and kw۴ were the most tolerant and sensitive genotypes to winter cold and had the highest and lowest seed yield, respectively. Genotypes that had more tolerance to winter cold had longer rosette period and correlation between them was negative and highly significant. Sensitive genotypes to winter cold because of lower density produced larger seed and the correlation between seed size and frost-bite percentage was positive and highly significant. Correlation coefficients among frost–bite percentage and plant height and oil percent were not significant.

Keywords:

Correlation coefficient , Covariance analysis , Rosette period , Seed yield , Soil surface temperature