Effect of terminal drought stress on seed yield and its components of some new winter rapeseed lines

Drought causes significant reductions in crop productivity in many parts of the world, including Iran. Identifying genotypes tolerant to drought stress is therefore one of the foremost goals of crop breeding programs. This study investigated the effect of terminal drought stress on yield and yield components of new winter rapeseed lines, and identified new winter rapeseed lines tolerant to terminal drought stress. A field experiment was conducted to evaluate 17 new winter rapeseed lines and two commercial cultivars (Ahmadi and Opera) under three moisture conditions (optimum irrigation, elimination of irrigation from flowering stage, and elimination of irrigation from silique stage) during two cropping seasons (2012-13 and 2013-14) at the Agricultural Research Station of Islamabad-e-Gharb, Kermanshah, Iran. Drought stress significantly affected all measured traits except days to flowering and 1000-seed weight. Based on the average of three conditions, KS7, KR4, L183, Opera, and HW118 had higher seed yields. These lines (except Opera) also produced higher seed yields when irrigation was eliminated from the flowering and silique development stages, and were identified as winter rapeseed lines tolerant to terminal drought stress with high seed yield potential underoptimum irrigation conditions.