The aim of this study was to clarify the effect of post-anthesis shading stress on the eating quality of indica rice in Chengdu Plain, so as to provide the theoretical and practical basis for the selecting of shade-tolerant rice varieties in low light rice region.

Field light control experiments were conducted in 2019 and 2020 in Wenjiang, Sichuan by using indica rice varieties with different amylose contents as materials. The effect of shading stress on eating quality of rice was studied by measuring the components and RVA spectrum values of rice, as well as the texture properties and eating quality of cooked rice.

(1)Shading stress significantly decreased amylose, amylopectin, and total starch contents of rice, but significantly increased the contents of protein and fat. (2)Shading stress significantly decreased the peak viscosity and breakdown of rice, while increased the pasting temperature and setback. (3)Shading stress also significantly increased the hardness of cooked rice, but decreased the stickiness and elasticity, which contributed to a significant reduction in the comprehensive score of cooked rice by decreasing both appearance and taste. (4)The results of principal component analysis showed that the rice components, RVA spectrum values, and texture properties could explain 81.2% of the total variation of eating quality of cooked rice. The comprehensive score of rice was significantly and positively correlated with the amylose, starch content, peak viscosity, breakdown, elasticity and stickiness, but negatively related to the protein and fat contents.

The protein and fat contents possessed greater influence on the eating quality of cooked rice than that of amylose and starch contents under shading stress. The shading stress leaded to significant variations in starch, protein, and fat components in rice, which contributed to a decrease in peak viscosity and breakdown, but an increase in pasting temperature and setback. And then, those variations contributed to the significantly decrease in eating quality of cooked rice by increasing the hardness, but decreasing both stickiness and elasticity of cooked rice.