Drought is a wide spread limiting problem seriously influencing rapeseed (Brassica napus L.) growth, production and quality, mostly in dryland regions. However, identification and development of resistant varieties is prohibited by destitute of effective selection criteria. The aim of this study was to evaluate the prevention possibility of rapeseed varieties against terminal-season water deficit stress through selecting suitable varieties. Thirty-four rapeseed varieties were tested in a split plot design based on randomized complete block design (RCBD) with four replications for two years (2005- 2006 and 2006-2007) at Seed and Plant Improvement Institute of Karaj, Iran. Two irrigation levels consisting of irrigation after 80 mm evaporation from class “A” pan during full growing season as normal irrigation (I) and water deficit stress (S) by restricting watering from the flowering phase until full maturity were established in main plots, and subplots were devoted to split application of varieties. Water deficit stress caused noticeable decrease in plant height, silique plant^-1, seed silique^-1, 1000-kernel weight, seed yield, oil percentage, oil yield and harvest index. There were significant positive correlations between seed yield and yield-related components. Meanwhile, the highest correlation was recorded for number of seeds per siliqua (r= 0.64; P < 0.01), suggesting that late-season water deficit stress could be used in selecting drought tolerant varieties. Among varieties, ‘Sunday’ produced the highest seed yield (4938 kg ha^-1) and oil yield (2317 kg ha^-1) in normal irrigation, and ‘ORW20-3002’ had the highest seed yield (2348 kg ha^-1) and oil yield (1000 kg ha^-1) in water deficit stress conditions. Accordingly, ‘ORW20-3002’ and ‘Sunday’ can be reported as varieties with sustainable productivity in stress and non-stress conditions.

oil yield; rapeseed; seed yield; water deficit stress

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia