关键词: 杂交粳稻, 常规粳稻, 收获时期, 品质

Abstract:

The effects of different harvest time on the rice quality of japonica hybrid rice and inbred japonica rice in Northern China were studied to provide the theoretical basis for improving the quality of hybrid japonica rice and inbred japonica rice through adjusting cultivation measures. Two hybrid japonica rice varieties and three inbred japonica rice varieties were used as test materials. Sampled every 7 days after 30 days from the full heading, quality traits were measured after air drying. The results showed that the effects of different harvest time on the brown rice rate, the milled rice rate and head rice rate of hybrid japonica rice and inbred japonica rice were significant. With the delay of harvest time, the brown rice rate and milled rice rate increased gradually and reached a maximum at 65 days after heading stage, and then decreased sharply. The head rice rate fluctuated significantly with no obvious regularity before 65 days after heading, but decreased significantly after 65 days after heading; The chalkiness rate and chalkiness degree of hybrid japonica rice showed an increasing trend. There was no significant difference on chalkiness rate and chalkiness degree in the inbred japonica rice varieties. An increasing trend was found on the whiteness value of the five cultivars. Most of the effects of different harvest time on the protein and amylose content did not reach a significant level. Except for Fengjin was no significant difference in taste value among different harvest time treatments, the other four varieties decreased with the postponement of harvest time and there was a significant difference at the level of 0.05 but no distinctive difference at the level of 0.01.During the same harvesting time, the processing quality (including brown rice rate, milled rice rate and head rice rate) of inbred japonica rice was significantly better than that of hybrid japonica rice, and the whiteness of hybrid japonica rice was significantly better than that of inbred japonica rice. The difference between inbred japonica rice and japonica hybrid rice on chalky grain rate and chalkiness degree was not significant, the same on amylose content, protein content and taste value. There were no significant differences on the best harvest time. The suitable delay of harvest could promote the improvement of processing quality, usually on 58 days after full heading. The suitable advance of harvest could promote the improvement of appearance quality and taste value, preferably from 30 to 37 days after full heading.

Key words: Hybrid japonica rice, Inbred japonica rice, Harvest time, Quality