Response of chalkiness in high-quality rice (Oryza sativa L.) to temperature across different ecological regions

Field experiments were conducted to determine the relationship between chalkiness of high-quality rice and temperature during grain filling period in 2016–2017. Significant differences in chalkiness and response to temperature during grain filling period were observed among the cultivars and years of production. A positive correlation between chalkiness and temperature that includes daily minimum temperature (T-min), daily mean temperature (T-mean) and daily maximum temperature (T-max) during grain filling period was observed. The correlation between chalkiness and T-min during 7 days after heading was lower than that of other stages, while the correlation between chalkiness and T-mean during the ripening stage was the highest than other stages. The chalkiness values of some varieties such as Jiuxiangzhan, Zhendao18 and Yongyou1538 were sensitive to temperature, however, it might be reached optimum level through suitable ecological regions. Other varieties such as Huanghuazhan, Wangxiangyouhuazhan and Ganchangjing1 could maintain lower level of chalkiness regardless of different ecological regions in southern China. These high-quality rice varieties with low and relatively stable chalkiness could be moderately planted in Chinese double-rice cropping systems, and could be used as breeding materials to cope with the adverse effects of future global temperature increase (mainly night temperature) on the appearance quality of rice.