【摘要】 【目的】为探寻四川盆地丘区一季中稻机插秧最适穴距和穴苗数配置，在保证产量同时提高群体质量和减少用秧（种）量，为该地区水稻机械化生产提供依据。【方法】以杂交中籼稻品香优玉稻为材料，采用两因素裂区设计大田试验，研究2种机插穴距（D1、D2）、3种穴苗数（G1、G2、G3）处理下水稻产量及产量构成因子、单茎与群体干物质积累和收获指数的差异及成因。【结果】不同穴距和穴苗数对千粒重、结实率的影响小，对穗粒数、穗数的影响大，对产量的影响不显著，其原因在于群体内部通过调节穗粒数与穗数的关系，在机插较大群体库容（颖花量）基础上实现水稻稳产；但相比于其他处理，D1G3可减少用秧量20.63%～60.44%。不同穴距和穴苗数对机插群体质量影响显著，且穴距较穴苗数作用更大，较宽穴距（22 cm）下单茎质量更优，收获指数更高，抗倒伏能力更强，因而群体质量更优。相关分析、通径分析和单茎穗粒数分布结果表明，机插条件下单茎质量与单茎籽粒重密切相关，而穗粒数是决定单茎籽粒重的最重要因子，较宽穴距下平均穗粒数较多的原因是大穗比例更高。【结论】机插中籼稻群体起点高，可通过适当扩大穴距合理稀植提高单茎质量促进大穗，进而提高收获指数和群体质量，保证较高产量同时减少用秧量；穴距22 cm、穴苗数3～4苗，是四川丘区中籼杂交稻机插的最佳配置。更多还原

【Abstract】 【Objective】 This study aims to identify the optimal plant spacing and seedling number per hill for mechanically transplanted single-crop mid-season rice in the hilly areas of the Sichuan Basin, with the goals of improving rice population quality, reducing seedling(seed) input, and maintaining yield, thereby providing a scientific basis for mechanized rice production in the region. 【Method】 Using the hybrid mid-season indica rice variety Pinxiangyou-Yudao, a field experiment with a two-factor split-plot design was conducted to evaluate the effects of two transplanting spacings(D1, D2) and three seedling number treatments(G1, G2, G3) on rice yield and its components, individual-plant and population dry matter accumulation, and harvest index. 【Result】 Different spacing and seedling number treatments had minimal effects on thousand-grain weight and seed-setting rate, but significantly influenced grains per panicle and panicle number. Yield differences were not significant across treatments, as the population compensated through trade-offs between grains per panicle and panicle number, achieving stable yield under a higher population spikelet capacity. Compared to other treatments, D1G3 reduced seedling usage by 20.63% to 60.44%. Both spacing and seedling number significantly affected population quality after mechanical transplanting, with spacing having a greater effect than seedling number. Wider spacing(22 cm) resulted in better individual-plant growth, higher harvest index, and stronger lodging resistance, leading to superior population quality. Correlation analysis, path analysis, and panicle size distribution indicated that individual-plant quality was closely related to grain weight per plant under mechanical transplanting conditions. Grains per panicle were the most critical factor determining individual-plant grain weight, and wider spacing increased the average grains per panicle by promoting a higher proportion of large panicles. 【Conclusion】 Mechanical transplanting of indica rice benefits from a high initial population capacity. Appropriately widening plant spacing and reducing seedling number per hill can improve individual-plant quality, promote large panicle formation, increase harvest index, and enhance population quality, thereby ensuring high yield with reduced seedling input. A configuration of 22 cm hill spacing with 3-4 seedlings per hill is recommended as the optimal practice for mechanized transplanting of mid-season hybrid rice in the hilly areas of Sichuan更多还原