Potted-Seedling Machine Transplantation Simultaneously Promotes Rice Yield, Grain Quality, and Lodging Resistance in China: A Meta-Analysis

Potted-seedling machine transplantation (PSMT) is an innovative method of mechanical rice transplanting to improve seedling quality and reduce mechanical injury relative to blanket-seedling machine transplantation (BSMT). However, the responses of yield, grain quality, and risk of lodging in rice to PSMT have not yet been comprehensively defined. Here, we present a meta-analysis of 67 peer-reviewed studies with 382 field observations to investigate the impacts of PSMT on rice yield, grain quality, and lodging resistance in mainland China. The results indicated that compared to BSMT, PSMT increased grain yield, aboveground biomass, and nitrogen uptake by an average of 8.4%, 6.2%, and 7.2%, respectively. PSMT boosted grain yield with hybrid rice (+10.2%) more strongly than with inbred rice (+6.9%). PSMT improved the brown rice rate (+0.74%), milled rice rate (+1.1%), head rice rate (+2.3%), and gel consistency (+4.4%) while reducing the amylose content by 3.7% with no significant effects on the chalky grain rate, chalkiness, length/width ratio, or protein content. The increase in the milled rice rate under PSMT was greater with hybrid rice than with inbred rice. PSMT reduced the lodging index at the first (-5.1%), second (-9.4%), and third (-8.0%) internodes. In conclusion, PSMT is a promising practice for simultaneously improving rice yield, milling quality, cooking and eating quality, and lodging resistance in paddies. In addition, the grain yield and milling quality of hybrid rice under PSMT are higher than those of inbred rice.