عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In order to investigate interaction of drought stress and potassium application on potassium, calcium, magnesium concentration and oil of two species of canola and mustard, a factorial experiment based on randomized complete block design with three replications was conducted during two years (2007-2009) at Agricultural and Natural Resources Research Station of Zehak located in Sistan and Baluchstan province. Irrigation regimes in three levels (irrigation after 50, 70 and 90 percent depletion of soil available water), potassium sulphate fertilizer in three levels (0, 150 and 250 kg.ha-1 K2SO4) and two species of Brassica napus (Hyola 401 Hybrid of canola) and Brassica juncea (landrace cultivar of mustard native of Indian) were allocated to experiment factors. According to the results two species showed different pattern of potassium and calcium accumulation in their leaves. Mustard contained a higher leaf potassium and calcium contents than canola. Under severe drought stress, leaf potassium and magnesium increased but calcium change was not significant. Increasing potassium application in the soil increased potassium and decreased calcium concentration in the leaf. Potassium application did not show any significant effect on leaf magnesium concentration. Hyola 401 showed higher seed yield, oil yield and oil content than landrace of mustard. Seed and oil yield increased but oil percent decreased with increasing drought stress. Potassium application caused increasing seed yield and oil yield in different levels of water availability in both species. Seed yield had positive correlation with oil yield, oil content and potassium concentration but its correlation with leaf calcium and magnesium concentration was negative. Based on the results of this experiment, it can be reported that equilibrium supply of potassium and moisture increased grain yield, oil production and absorb of mineral nutrients in both species and property variation in nutrients absorption efficiency in brassica genus can be used in breeding programs for drought tolerance.