Objective  The study was conducted to explore the comprehensive effects of nitrogen and phosphorus regulation on the yield and quality of hybrid rice, and the response of rice quality of high-quality rice varieties to nitrogen and phosphorus regulation under environmental conditions in Sichuan rice region.

Method  The hybrid rice Deyou 4727 was treated with 4 levels(0, 90, 150, 270 kg/hm²)of nitrogen and 4 levels(0, 30, 60, 120 kg/hm²)of phosphorus. The grain yield characters, milling quality, appearance quality, taste value, RVA profile characteristic value and amylose content were determined to explore the response of grain yield and quality to nitrogen and phosphorus regulation.

Result  With the increase of nitrogen fertilizer application rate, the yield of Deyou 4727 increased significantly, and the yield reached the maximum under the condition of 270 kg/hm², while the effect of phosphate fertilizer on rice yield was not significant. The effects of nitrogen fertilizer and phosphate fertilizer treatments on milling quality and appearance quality reached significant or extremely significant levels: with the increase of nitrogen fertilizer application rate, the brown rice rate, chalkiness and chalky grain rate of Deyou 4727 showed a trend of first decreasing and then increasing. The polished rice rate showed a decreasing trend, and the head rice rate first increased and then decreased. Phosphate fertilizer application could increase the brown rice rate, polished rice rate and head rice rate of Deyou 4727, and reduce the chalkiness of rice. There was a significant correlation between the application of nitrogen fertilizer and phosphate fertilizer and rice cooking and eating quality: nitrogen fertilizer had a very significant positive correlation with paste temperature, and a very significant negative correlation with amylose content; phosphate fertilizer had an extremely significant negative relationship with peak viscosity, hot paste viscosity and cold paste viscosity, and a significant negative relationship with the disintegration value. With the application of nitrogen fertilizer, Deyou 4727 significantly reduced the eating quality, which decreased by 4.37%, 10.90% and 12.13% respectively under the low, medium and high nitrogen treatments.

Conclusion  By appropriately increasing the application amount of nitrogen fertilizer and controlling the input of phosphate fertilizer at the same time, better quality can be obtained under the premise of ensuring the yield of rice.