Changes in Rice Yield and Quality from 1994 to 2023 in Shanghai, China

In recent years, there has been widespread cultivation of high-quality rice along the southeast coast of China, particularly in Shanghai. However, the specific changes in the yield and quality performance of rice in the Shanghai region have not been well understood. A study conducted on 194 rice varieties in the Shanghai region from 1994 to 2023 focused on yield, growth characteristics, and quality. The findings revealed significant increases in rice yield (+16.8%) and spikelets per panicle (+45.4%) in the Shanghai region over the past 30 years, along with a decrease in amylose content (−27.9%). However, parameters such as grain filling, 1000-grain weight, plant height, panicle length, chalkiness, and gel consistency showed no significant changes over the same period. Additionally, the study found that the yield, nitrogen application amount, growth period, and head rice rate of japonica rice and indica-japonica hybrid rice were higher than those of indica rice, although the panicle length was lower in comparison. Japonica inbred rice exhibited the lowest amylose content and superior taste. Correlation analyses suggested that the breeding of japonica rice varieties in the Shanghai region should focus on balancing nitrogen absorption and high chalkiness, plant biomass, and amylose content, and yield and the appearance and taste quality of rice. In addition, the potential rice yield per unit area in the Shanghai region in the future depends on the promotion of hybrid japonica rice planting and developing best management practices.