关键词: 水稻, 食味, 直链淀粉, 蛋白质, 粒厚, 光合速率

Abstract: In order to identify the quality characteristics of high quality rice varieties and its relationship with leaf photosynthesis，breed and screen new rice varieties with good taste, eight high-quality rice varieties along the Yellow River rice area in Henan province were used as experimental materials under field cultivation. This study measured and analyzed rice amylose content, protein content, processing quality characteristics (brown rice rate, milled rice rate, head rice rate) and appearance quality characteristics (chalky grain rate and chalkiness), and measured the photosynthetic rate of sword leaf in the grain-filling stage. The results showed that the brown rice rate, milled rice rate and head rice rate of eight excellent rice varieties were higher, the coefficient of variation among the varieties was lower. The chalky grain rate and chalkiness varied among rice varieties, and their coefficients of variation among the varieties were 39.73% and 36.49%, respectively. The coefficients of variation of amylose content, protein content and taste value affecting taste qualities of rice were relatively small, less than 5%. The correlation analysis showed that the protein content had a significant left-biased parabolic relationship with the food taste value（r=0.827*）, the straight-chain starch content had a very significant negative correlation with taste value (r=-0.905**). The grain thickness of brown rice had a significant open-down parabolic relationship with the taste value（r=0.747*）. The appearance quality, protein content and taste value were negatively correlated with leaf photosynthetic rate in the middle and late grain filling stage, but positively correlated with amylose content. These results showed that the lower the content of protein and amylose, the better taste quality of rice. The taste quality became better with the increase of grain thickness in a certain range, but decreased with the grain thickness of brown rice exceeding more than 2.1 mm. Increasing the photosynthetic rate of rice leaves in the middle and late grain filling stage could help to improve the appearance and nutritional quality of rice, while the increase of  amylase content led to the reduction of rice taste value. Therefore, the high photosynthetic efficiency of rice leaves had some certain selection pressure in the quality rice breeding. It was of great significance for improving taste quality of rice by reasonably regulating the photosynthetic rate of leaves in the middle and late grain filling stage.

Key words: rice, food taste, amylose, protein, grain thickness, photosynthetic rate