Abstract: It is important to clear the relationships of growth duration with rice yield and quality in determining the breeding objectives and cultivation strategies. In this paper, plants of japonica rice varieties Ning 111 and Chunjiang 302 with different growth durations resulted from short-day treatment were used to investigate the changes of yield and rice quality. The results showed that, the growth duration of more than 152 d had little effect on yield, but when less than 152 d, there was a significant positive correlation between growth duration and yield or dry matter accumulation; the smallest length and width of rice, as well as lowest protein content and setback of amylum were observed in the treatment G2 or G3, which had moderate growth duration of 131–132 d, the growth duration more than or less than 131–132 d would both increase the values of these rice quality indices; amylose content also showed a similar trend, and the minimum value in two species all appeared in treatment G3 (132 or 137d), while for breakdown of amylum, the trend was just opposite. The percentage of chalky grains, chalkiness and gelatinization temperature in two varieties rose with shortening growth duration; the effects of growth duration on milling quality were generally lower.

Key words: Rice, Growth duration, Yield, Rice quality