Occurrence of rice preharvest sprouting varies greatly depending on past weather conditions during grain filling

Rice (Oryza sativa L.) preharvest sprouting (PHS) has been reported to be affected by the number of days after heading, the temperature, and the level of continuous rainfall at the time of PHS induction (i.e. maturity). However, the environmental conditions to which the crop is exposed earlier in the season, such as during grain filling, may also contribute to the occurrence of PHS. This study therefore analysed the effect of environmental factors on PHS occurrence during grain filling. For two consecutive years, differences in environmental factors during grain filling were produced by varying the transplanting date and rainfall exposure under identical accumulated temperatures of 1200 degrees C after heading. Although identical PHS induction treatments were performed, the intercultivar differences in PHS occurrence exceeded the intracultivar differences and depended on the weather conditions of the grain filling period. The PHS occurrence rate was most significantly influenced by the average temperature during this period and the amount of rainfall during temperature accumulation to similar to 1200 degrees C. Based on these findings, studies related to preharvest sprouting can be conducted to produce more reproducible data. The results from this study can also support planting and transplanting planning in order to reduce pre-harvest damage by avoiding high temperatures during maturation.

Automated summary

This study investigated the impact of environmental factors on preharvest sprouting in rice, finding that temperature and rainfall significantly influenced the sprouting rate.