Effects of water-nitrogen interaction on grain protein quality, nitrogen use efficiency and water use efficiency of Jimai 20.

The field experiments were carried out to determine the effects of water-nitrogen interaction on the protein quality,nitrogen and water use efficiency of strong gluten wheat Jimai20.Three nitrogen application treatments N0(0 kg·hm-2),N1(180 kg·hm-2),and N2(240 kg·hm-2),and four irrigation treatments W0(no irrigation),W1(irrigation before sowing,at jointing stage and at anthesis),W2(irrigation before sowing,before winter,at jointing stage and at anthesis) and W3(irrigation before sowing,before winter,at jointing,at anthesis and at grain filling stages) under each nitrogen treatment were set.The results showed that the activity of nitrate reductase(NR),glutamine synthetase(GS),endopeptidase(EP),carboxypeptidase(CP) and aminopeptidase(AP) in flag leaf were highest under N2 treatment and lowest under N0 treatment.Under the same nitrogen fertilizer rate,the W0 treatment got the lowest NR and GS activities,and W3 treatment had the higher NR and GS activities at later grain filling stage than that W1 and W2 treatments,but the EP、CP and AP activities were lower than that under W1 and W2 treatments.The protein content was the highest under W3 treatment when the nitrogen rate was 0 kg·hm-2,and there were no significant difference among W1,W2 and W3 treatments when the nitrogen rate were 180 and 240 kg·hm-2.The sedimentation volume,wet gluten content,dough stability time,grain yield,N apparent recovery rate,N productive efficiency and water use efficiency were the highest under N1 treatment.Sedimentation volume was the highest under W1 treatment,and there were no significantly difference on wet gluten content,dough stability time,grain yield,N apparent recovery rate,N productive efficiency between W1 and W2 treatments,but were higher than that of W0 and W3 treatments.The water use efficiency was higher under W1 treatment than those of W2 and W3 treatments.All the results above suggested that the N1W1,with 180kg N·hm-2 and three times irrigation(irrigation before sowing,at jointing stage and at anthesis),was the best treatment with high yield,good quality and high efficiency.