Yield performance of inbred rice grown under labor-saving crop establishment methods

Labor-saving crop establishment methods have rapidly developed for rice (Oryza sativa L.) production in China to address a labor shortage in agricultural production resulting from urban expansion, and many rice farmers who adopt such methods prefer to choose inbred varieties with reduced seed costs. This study aimed to determine which of two labor-saving establishment methods, zero tillage and direct seeding (ZTDS) and rotavator tillage and mechanical transplanting (RTMT), achieves higher grain yield in inbred rice. Field experiments were conducted at two sites across 3 yr to determine grain yield and yield attributes of elite inbred rice cultivar Jinlongsimiao, established under ZTDS and RTMT. Results showed that RTMT produced an 11% higher grain yield than ZTDS. Higher spikelet number per panicle was observed under RTMT compared with ZTDS, but spikelet number per square meter was not necessarily higher because it was compensated for by a reduced panicle number per square meter. The RTMT-established rice conferred higher spikelet filling percentage but lower grain weight than ZTDS-established rice. There was no consistent or significant difference in crop growth rate, total biomass production, or the source/sink ratio between RTMT and ZTDS rice. The RTMT method produced a higher harvest index than ZTDS. These results suggest that RTMT is the favorable method for inbred rice establishment to improve the partitioning of assimilates and, consequently, increase spikelet filling percentage and grain yield compared with ZTDS.