Abstract: Typical indica and japonica cultivars, cultivars with wide compatibility, indicaclinous and japonicaclinous strains and restoring lines were collected and crossed in this study. Twenty five F₁ hybrids between indica and japonica subspecies were selected and divided into five groups. Using characters such as biomass yield, straw weight, plant height, days from seeding to heading, number of spikelets per panicle, number of grains per panicle and seed-setting rate as basic data, transgressive heterosis and competitive heterosis for each combination were determined. The results showed that there existed a correlation between straw weight and seed - setting rate in F₁ hybrids between indica and japonica subspecies, and that the vigor contained two parts: usable and unusable. The heterosis in a typical indica-japonica F₁ hybrid was hard to use. However, pairing a wide compatibility line With an indicaclinous or a japonicaclinous restoring line or their derivatives, or pairing a wide compatibility line with another wide compatibility line, would allow partial use of the heterosis in hybrids between the two subspecies, and therefore should be emphoyed as an important breeding strategy in better use of the heterosis at present.

Key words: Indica-Japonica hybrid, Heterosis, Vegetative heterosis, Reproductive heterosis, Usability of heterosis

摘要： 搜集典型籼粳品种、广亲和品种、偏籼或偏粳品系及恢复系并进行杂交。选取25个籼粳亚种间杂种F1，将其划分为5类。以这5类25个组合的生物产量、茎叶重、秆高、出穗期、每穗颖花数、实粒数、结实率等性状为基本资料，分别计算其超亲优势与竞争优势。结果指出：籼粳亚种间杂种F1茎叶重与结实率存在负相关，杂种优势含可利用与非可利用两部分，典型籼粳F1杂种优势是难以利用的，利用广亲和系与偏籼或偏粳恢复系及其派生系或者偏籼广亲和系和偏粳广亲和系配组，实现部分利用亚种间杂种优势，应作为当前亚种间杂种优势利用育种战略的重要措施。

关键词: 籼粳亚种, 杂种优势, 营养优势, 生殖优势, 可利用性