Effects of drought stress on agronomic traits and yield of different rapeseed genotypes

The agronomic traits and yield components of rapeseed under drought stress during early flowering stage were studied for drought-tolerance breeding. Thirty genotypes of rapeseed were measured for plant height,number of branches,inflorescence length,number of pods,number of seeds per pod,weight of 1 000 seeds and yield. The plant height,number of primary branches,inflorescence length,number of pods on main inflorescence,number of pods per plant,number of seeds per pod and yield per plant decreased under drought stress,however,the weight of 1 000 seeds increased. The drought tolerance coefficients of plant height,number of primary branches,inflorescence length,number of pods on main inflorescence,pod length,number of pods per plant,number of seeds per pod and yield per plant showed highly significant correlations with the comprehensive evaluation value of drought tolerance,indicating that these traits can be used as indicators for drought tolerance indentification. Thirty genotypes of rapeseed were clustered into three groups based on the comprehensive evaluation value of drought tolerance,which were tolerant,moderately tolerant and sensitive. Three varieties,Fengyou730,Yangguang2009 and Xunyou8 are drought tolerant.