Comparison of agronomic performance between inter-sub-specific hybrid and inbred japonica rice under different mechanical transplanting methods

摘要

Mechanical transplanting has been applied to rice cultivation to save labor costs and ease labor shortages in Asian countries,especially in China. However, little information is available related to the characteristics of agronomic performance whencomparing inter-sub-specific hybrid rice （!HR） and inbred japonica rice （I JR） under mechanical transplanting method. In2013 and 2014, field experiments were conducted using IHR （Yongyou 2640） and I JR （Wuyunjing 24） under two cultivationpatterns, that is, pot seedlings mechanically transplanted （PS） and carpet seedlings mechanically transplanted （CS）.Grain yield, yield components, leaf area index （LAI）, leaf area duration （LAD）, aboveground biomass, crop growth rate（CGR）, nitrogen （N） uPtake, and N accumulation were investigated. When compared with CS, PS displayed significantlyincreased grain yield for both varieties because the larger sink size allowed higher N accumulation from panicle initiationto maturity. Moreover, total aboveground biomass under PS increased significantly compared with that under CS; thatis, higher photosynthetic productivity resulted from a greater LAI and higher LAD during the grain filling stage. Higher Nabsorption capacity in the middle and late growth periods resulted in significantly enhanced total N uptake under PS. Whencompared with I JR for both treatments, IHR generated 75.2% more grain yield. However, the characteristics creating highyield of IHR were different from those of I JR. Greater aboveground biomass production as well as higher N uptake andaccumulation created higher grain yield in IHR than in I JR. These results suggest higher yield could be achieved using PSwith IHR, attributing to exploit both yield superiority and productive potential.