Journal of Crop Breeding

Drought is one of the most important abiotic stress factors worldwide that affects growth, development and final yield of crops. In order to evaluate the different genotypes of rapeseed under water stress conditions, an experiment was carried out as a split-plot design based on randomized complete block design (RCBD) with three replications. Three irrigation levels were applied in main plot included: non water stress, water stress from flowering stage and water stress from pod formation stages to growth of the seed and 14 different genotypes was in the sub factor. The results showed that there was a significantly variation among the genotypes based on the different traits studied at different levels of water stress. Water deficit stress reduced all studied traits except the harvest index. The cluster analysis of different genotypes of rapeseed based on UPGMA method at different levels non-stress, water stress from flowering stage and pod formation stage, distinguished genotypes in 3, 4 and 4 groups, respectively. In principal component analysis two factors was found at all levels of water stress, which had an eigenvalue higher than one. Pod length, pod area, number of pods per plant, number of seeds per pod, absolute growth rate, grain yield and harvest index at all stress levels were the highest factor load in the positive direction (1% level). In water stress at flowering stage level, grain yield showed significant correlation with all traits except plant height and number of actual pods to potential. The results of the experiments showed that in non-stress conditions, L155(3929 ha^-1), L14 (3947 ha^-1), HL2012 (3952 ha^-1) and WPN6 (4159 ha^-1) genotypes had suitable yields, but under water stress conditions at flowering stage WPN6 (2156 ha ^-1), L155 (2158 ha ^-1), SW102 (1983 ha^-1), L14 (2174 ha^-1) and HL3721 (2136 ha^-1) genotypes and under water stress at the pod formation stages, the genotype HL2012 (3295 ha^-1) had a significantly higher grain yield than that of other genotypes.