Response of seed quantity and quality of promising winter rapeseed genotypes to terminal water limitation

The present research was conducted to evaluate the effect of terminal drought stress on quantity and quality of seeds produced from six promising genotypes of winter rapeseed in East-Azerbaijan Research center for Agriculture and Natural Resources during growing season 2014-15. The factorial experiment based on randomized complete block design was laid out in three replicates including two factors of genotype (six winter rapeseed genotypes called Karaj2, Karaj3, KS7, L5, L146, L210) and water limitation (three levels of water deficit stress viz. full irrigation IW1, irrigation withholding from anthesis IW2 and irrigation withholding from seed set IW3). Imposing water restriction from anthesis caused more loss of silque and seed number and final yield. The least loss of seed yield obtained from L5 and L210 genotypes under drought stress during anthesis. The greatest and lowest fall in seed germinability were recorded in L146 under drought stress from anthesis and L5 and L210 under the same stress level, respectively. Under water limitation from anthesis, the least increase of seed electroconductivity was observed in genotype L5. The greatest length and vigor index of seedling was observed in genotypes L5 and L210 under irrigation withholding from flowering. In general, occurring terminal drought stress especially during anthesis of rapeseed caused significant drop in seed production, both quantitatively and qualitatively. On the other hand, genotypes L5 and L210 had the best yield under stress condition and would recommended for introducing to breeding program of drought stress tolerance.