Grain-Filling Characteristics and Yield Formation of Rice at Saline Field

Abstract

It is of great interest to utilize saline fields to promote rice production in China. It has still not been established how salinity stress affects grain-filling characteristics and the relationships with yield formation of rice in a saline field. This experiment was conducted with Ningjing 7 (salinity-tolerant rice variety) and Wuyunjing 30 (salinity-susceptible rice variety) in a non-saline field and a high-saline field in 2021 and 2022. The grain yields of Ningjing 7 and Wuyunjing 30 in a high-saline field were 37.7% and 49.8% lower (p p p p < 0.05) than those in a non-saline field, and the reductions were more pronounced for Wuyunjing 30. The maximum grain-filling rate and mean grain-filling rate were decreased, while the time to achieve the maximum grain-filling rate was increased in a high-saline field compared to a non-saline field, especially for Wuyunjing 30. The mean grain-filling rate and grain-filling amount in superior and inferior grains during the early, middle, and late stages were lower in a high-saline field than in a non-saline field. For Ningjing 7 and Wuyunjing 30, the reductions in the grain-filling amount in the inferior grains during the early, middle, and late stages in a high-saline field were greater than those in superior grains. Our results suggest that salinity stress inhibited the grain-filling rate, reduced the total starch content and affected key enzyme activities, which led to the poor sink-filling efficiency and yield performance of rice in a saline field, especially for the salinity-susceptible variety.

Keywords

• rice
• salinity stress
• grain yield
• grain-filling characteristics
• starch formation