沿江双季稻北缘区机插早稻的超高产群体特征

【目的】研究安徽沿江双季稻北缘区不同机插高产早稻品种产量差异及超高产品种的群体共性特征,为品种选育与精确定量栽培提供参考。【方法】试验于2018—2019年在安徽庐江进行,采用前期筛选获得的9个高产早稻品种为供试材料,分析不同品种的产量及构成、干物质积累、叶面积指数、有效光截获和利用率的差异。【结果】不同高产品种的产量间存在显著差异,通过聚类分析可进一步分为超高产（9.1—9.5 t·hm ^-2）、更高产（8.1—8.6 t·hm ^-2）和高产（7.6—7.8 t·hm ^-2）3种类型。超高产类型品种较更高产和高产类型品种显著提高了每穗粒数、颖花量和千粒重。超高产类型品种的平均日产量为82.4 kg·hm ^-2·d ^-1,分别较更高产和高产类型品种提高10.2%和19.8%。干物质积累量是不同类型品种产量差异的主要原因,与更高产和高产类型品种相比,超高产类型品种显著提高水稻中后期的阶段干物质积累量18.3%—21.4%。超高产类型品种具有更高的中后期有效光截获量和光截获利用效率,分别与其高的叶面积指数和库容量有关。相关性分析表明,穗分化期和抽穗期群体有效光截获量分别与每穗粒数和千粒重呈显著正相关,且超高产类型品种具有更高的响应效率。另外,与更高产和高产类型品种相比,超高产类型品种显著提高抽穗期总粒重/叶4.1%—11.3%,这与其高的中后期光截获利用率密切相关。【结论】沿江双季稻北缘区机插早稻品种适宜选用叶面积指数高（穗分化期5.6—6.0、抽穗期7.1—7.3）、穗粒数多（124—132）、千粒重高（25.8—27.0 g）,且日产量为80.8—83.7 kg·hm ^-2·d ^-1的品种,可获得超高产水平（>9.0 t·hm ^-2）。

Super-High Yield Characteristics of Mechanically Transplanting Double- Cropping Early Rice in the Northern Margin Area of Yangtze River

【Objective】The aim of this study was to identify the differences of yields among various high-yield varieties of double-cropping rice with machine-transplanted under the early season and the common characteristics of super-high yield varieties in the Northern Margin Area of Yangtze River. 【Method】In this study, nine pre-screening high yield varieties were compared for their yield formation, including dry matter accumulation (DMA), leaf area index (LAI) and the intercepted photosynthetically active radiation (IPAR), in field experiments in the early season of 2018 and 2019 in Lujiang county, Anhui province, China.【Result】The rice grain yields varied across the different high-yield varieties. Through cluster analysis, it could be further divided into three yield types: super-high yield (9.1-9.5 t·hm ^-2), higher yield (8.1-8.6 t·hm ^-2) and high yield (7.6-7.8 t·hm ^-2). Compared with higher yield and high yield varieties, the super-high yield varieties showed more spikelets per panicle, total spikelets and 1000-grain weight. The average daily yield of super-high yield was 82.4 kg·hm ^-2·d ^-1, 10.2% and 19.8% higher than that of higher yield and high yield, respectively. DMA was the main reason for the differences in yield among various varieties. The DMA of super-high yield varieties was 18.3%-21.4% higher than that of higher yield and high yield varieties from panicle initiation stage to maturity stage. Super-high yield varieties showed higher IPAR and the photosynthetically active radiation use efficiency (PUE) was related to the higher LAI and sink. IPAR in panicle initiation and heading stage was significantly positively correlated with the spikelets per panicle and 1000-grain weight, respectively. However, the super-high yield varieties showed higher response to the IPAR. The grain weight/leaf of super-high yield varieties was 4.1%-11.3% higher than higher yield and high yield varieties, which was related to the higher PUE from panicle initiation stage to maturity stage. 【Conclusion】 The common characteristics of super-high yield early rice varieties (>9.0 t·hm ^-2) were higher LAI (panicle initiation stage 5.6-6.0, heading stage 7.1-7.3), higher spikelet numbers per panicle (124-132), higher 1000-grain weight (25.8-27.0 g) and higher average daily yield (80.8-83.7 kg·hm ^-2·d ^-1) under machine-transplanted in the Northern Margin Area of Yangtze River.