Effects of nitrogen applied rate and transplanting density on grain quality of japonica rice.

Using Liaoyou 5218,a japonica hybrid rice variety,and Liaoxing 1,a japonica inbred rice variety,as the materials,the effects of nitrogen rate(N) and transplanting density(D) were studied on grain quality of japonica rice.The results showed that the chalky rice percentage(CP) and chalkiness degree(CD) of Liaoyou 5218 were significantly higher than those of Liaoxing 1.There were no significant effects of N and D on CP,CD and the length-width ratio of milled rice(L/W) in both varieties.Increasing N or decreasing D raised the level of protein content(PC) but lowered the taste value(TV) of the grains of both varieties.However,the effects of N and D on the amylose content(AC) varied with the variety(V).It is found that lower N and higher D would improve the nutritive and eating quality of both japonica hybrid and inbred rice varieties,but the higher CP and CD of japonica hybrid rice could only be improved through breeding methods since cultivation practices have not a remarkable effect on them.