It is widely reported that japonica/indica hybrids (JIH) have superior grain yield over other main varietal groups such as indica hybrids (IH) under sufficient resource inputs. To date, little attention has been paid to yield performance of JIH under input-reduced practices, and whether JIH could have better grain yield performance over IH under input-reduced practices. In this study, three JIH varieties and three IH varieties were compared in grain yield and their related morpho-physiological traits under two cultivation modes, i.e., conventional high-yielding method (CHYM) and double reductions in nitrogen rate and planting density (DRNP). Our results showed that JIH had 8.3 and 13.3% higher grain yield over IH under CHYM and DRNP, respectively. The superior grain yield of JIH over IH under DRNP was mainly attributed to larger sink size and improved sink filling efficiency. Three main morpho-physiological traits were concluded for better yield performance of JIH over IH under DRNP. Firstly, JIH had the reduced unproductive tillers growth, indicated by a higher percentage of productive tillers and the percentage of effective leaf area index (LAI) to total LAI at heading stage. Secondly, a synergistic increase in biomass accumulation and harvest index were achieved of JIH, supported by higher biomass accumulation and leaf area duration during the main growth periods, and improved non-structural carbohydrate (NSC) remobilization after heading. Thirdly, JIH had an improved canopy structure, showing as higher leaf area of upper three leaves and lower light extinction coefficient. Our results suggested that improved morpho-physiological traits of JIH could lead to better grain yield performance over IH under input-reduced practices.

据广泛报道，粳/ ind杂种（JIH）的谷物产量优于其他主要品种，例如in足够的资源投入下的混合动力车（IH）。迄今为止，很少有人关注减少投入的实践下JIH的产量表现，以及在减少投入的实践下JIH是否可以比IH有更好的谷物产量表现。在这项研究中，比较了三种JIH品种和三种IH品种在两种耕种模式下的谷物产量及其相关形态生理性状，即传统的高产方法（CHYM）和氮肥和种植密度双倍降低（DRNP） 。我们的结果表明，在CHYM和DRNP条件下，JIH的谷物单产分别比IH高8.3％和13.3％。在DRNP条件下，JIH的谷物单产高于IH，这主要归因于更大的汇池尺寸和更高的汇池填充效率。在DRNP条件下，总结出三个主要的形态生理性状，即JIH优于IH的产量表现。首先，JIH的非生产性分ers生长减少，表现为抽穗期较高的生产性分percentage和有效叶面积指数（LAI）占总LAI的百分比。其次，在主要生长期较高的生物量积累和叶面积持续时间以及抽穗后改善的非结构性碳水化合物（NSC）固定化的支持下，JIH的生物量积累和收获指数实现了协同增加。第三，JIH的冠层结构得到了改善，表现为上三叶的叶面积更大，而光消光系数更低。