RT - Journal Article T1 - Effect of potassium fertilizer and irrigation levels on grain yield and water use efficiency of rapeseed (Brassica napus L.) and Indian mustard (Brassica juncea L.) species JF - agrobreed YR - 2009 JO - agrobreed VO - 11 IS - 3 UR - http://agrobreedjournal.ir/article-1-205-en.html SP - 271 EP - 289 K1 - Grain yield K1 - Indian mustard K1 - Potassium fertilizer K1 - Rapeseed and Water Use Efficiency. AB - To study the effect of potassium fertilizer under different irrigation levels on grain yield and water use efficiency of two rapeseed (Brassica napus L.) and Indian mustard ( Brassica juncea L.) a field experiment was conducted in a factorial experiment using randomized complete block with three replications at Zahak field station, Agricultural and Natural Resources Research Center of Sistan in 2007-2008 cropping season. Three irrigation levels including (S1=irrigation after 50 percentage depletion of soil water (control), S2 =irrigation after 70 percentage depletion of soil water and S3 =irrigation after 90 percentage depletion of soil water), two Brassica species (Hyola401 Hybrid and a landrace of Indian mustard) and three levels of potassium fertilizer (K0=0 ,K1=150 and K2= 250 kg.ha-1 K2SO4) comprised the experimental factors. Results showed that the effects of irrigation levels, Brassica species and potassium fertilizer on grain yield, number of silique.plant-1, number of grain.silique-1, number of aborted silique. Plant-1, 1000 grain weight and water use efficiency was significant. Considering grain yield and water use efficiency Hyola401 performed better than Indian mustard landrace by 17% and 15%, respectively. Production efficiency of rapeseed was higher in this experimental condition. With increasing stress intensity, grain yield reduced and water use efficiency increased significantly. Grain yield in severe water stress treatment (S3 ) was 27% lower than the control (S1), however, water use efficiency increased by 16%. Increasing water use efficiency reduced water used in S2 and S3 treatments by 7% and 39% as compared with control (S1). With increasing potassium application rate, negative effect of water stress on grain yield was ameliorated and grain yield improved. Application of 250 kg.ha-1 of potassium increased grain yield and water use efficiency by 21% and 22%, respectively. Interaction of irrigation × potassium application was significant for grain yield, water use efficiency and number of aborted silique.plant-1, but not for the other traits. The results also showed that in S3 treatment differences between lowest grain yield at K0 and highest grain yield at K2 was 779 kg.ha-1 which was 52% greater than the control. Results of this study showed that potassium application can positively affect grain yield and water use efficiency of rapeseed in severe and mild stress conditions. It is concluded that potassium application was effective on plant growth and formation of economic yield in conditions of Sistan region by ameliorating damages caused due to water stress. LA eng UL http://agrobreedjournal.ir/article-1-205-en.html M3 ER -