The assessment of water stress and delay cropping on quantitative and qualitative traits of rapeseed genotypes

Abstract

To investigate the effects of water stress and delay cropping on the qualitative and quantitative traits of rapeseed genotypes, a factorial split-plot test was conducted in a complete randomized blocks design with three replications in Karaj, Iran. In this experiment, cultivations at two levels included well-timed cultivation (Oct. 7) and delay cropping (Nov. 1). The irrigation was conducted at two levels routine irrigation (control) and the elimination of watering after pod formation stage in factorial status in main plots and five rapeseed genotypes including HW2, HW1, SW102, BAL4, BAL1 and Okapi in subplots. The interaction effect of cultivation date × irrigation on the seed yield and erucic acid traits was significant at 5% level, and on the trait of oil yield was significant at 1% level. The interaction effect of cultivation date × cultivar was significant at 1% level on the traits of stearic acid, oleic acid and seed glucosinolate. The genotypes SW102 and HW1, having the maximum quantity of standard erucic acid, allocated maximum seed yield of 3877 and 3801 k/ha, respectively. Moreover, these two genotypes, containing maximum amount of oleic acid on average of 64.4 and 63.4% and minimum amount of seed glucosinolate on average of 23.5 and 23.8 μmol/g of meal in the delay cropping condition, are recommendable to be cultivated under delay cropping conditions. Therefore, by introducing of suitable varieties for delay cropping as well as by selection of varieties that produce reasonable economical yield and standard qualitative traits, it is possible to increase the under cultivation areas of this plant in the cold and temperate-cold regions with dry and semi-dry climates.