Critical yield components for achieving high annual grain yield in ratoon rice

Ratoon rice is considered an eco-friendly and resource-efficient method for rice cultivation, providing innovative strategies to mitigate the global food crisis. To clarify the critical yield components for achieving high annual grain yield in ratoon rice, data from 136 widely cultivated rice cultivars were collected through a six-year field experiment. The study analyzed the correlations between yield components and yields for both the main season and the ratoon season, indicating that main yields vary between 5.9 and 10.9 Mg ha^-1, exhibiting a highly significant positive correlation with spikelets per panicle; ratoon yields range from 1.8 to 7.1 Mg ha^-1, showing a highly significant positive correlation with panicles per m², grain filling rate, and 1000-grain weight. Path analysis reveals that, in terms of contributing to ratoon yield, the grain filling rate is the most influential component, followed by panicles per m², and 1000-grain weight. Therefore, by selecting large-panicle cultivars in the main season and enhancing panicles per m², grain filling rate, and grain weight in the ratoon season, high annual yield in ratoon rice can be realized.