Effects of nitrogen levels on grain yield and quality of rice

With a typical indica hybrid Shanyou 63 and a japonica cultivar Wuyujing 3 as materials and six nitrogen levels,0,8,16,24,32 and 40 g·m-2,as treatment factors,the effects of nitrogen levels on the grain yield and quality were investigated under field-grown conditions.The results showed that nitrogen levels,ranged from 0 to 40 g·m-2,had no significant effect on brown rice,milled rice,kernel length/kernel width,and amylose content.The protein content was increased with the increase of nitrogen levels.The panicle number,spikelets per panicle,grain yield,head rice,peak viscosity,and values of breakdown in rapid viscosity analyzer(RVA) profiles were increased,whereas chalky grains,chalkiness,setback values were reduced,when the nitrogen level was from 0 to 16 g·m-2 for Shanyou 63 and from 0 to 24 g·m-2 for Wuyujing 3.The filled grains,1000-grain weight,grain yield,head rice,peak viscosity,and values of breakdown decreased,whereas chalky grains,chalkiness,setback values increased,when the nitrogen level was higher than 16 g·m-2 for Shanyou 63 and higher than 24 g·m-2 for Wuyujing 3.The results indicated that the nitrogen rate at 160 and 240 kg·hm-2 could be as an optimum amount of nitrogen application for Shanyou 63 and Wuyujing 3,respectively,in the production for the high yield and good quality of rice.