Abstract: Dormancy indexes of hulled and dehulled seeds were investigated by using 109 F1 hybrids and their 19 cytoplasmic male sterile(CMS) lines and 9 restorer lines in indica hybrid rice. The seeds of each F1 and the parents were harvested at 35 days after flowering. Meanwhile, combining ability was analyzed in 25 combinations made by 5 CMS lines and 5 restorer lines (NCⅡ genetic design). The results showed that the seed dormancy index of F1 was positively and highly significantly correlated with those of their parents and midparent value. Out of the 109 combinations, 82 showed midparent heterosis, and 43 heterobeltiosis. Seed dormancy index of F1 and their parents declined dramatically in dehulled seeds compared with hulled seeds, indicating that the hull played an important role in seed dormancy. However, the trend was similar in hulled and dehulled seeds in terms of relationship between F1 and their parents in seed dormancy. The influence of hull on seed dormancy depended mainly on F1 genotype, not on hull itself of maternal parent. The variance of general combining ability(GCA) in female and male parents occupied 592% and 31.1% of total variance, respectively. The variance of specific combining ability(SCA) in combinations occupied 97% of total variance, indicating that gene additive effects were principal. Among the 5 CMS lines, Ⅱ112A had the highest GCA effect for seed dormancy, followed by D62A. Among the 5 restorer lines, IR112 had the highest GCA effect for seed dormancy followed by 2786. They were excellent materials as parents for breeding F1 hybrid rice with stronger seed dormancy.

Key words: hybrid rice, dormancy, multiple regression, general combining ability, specific combining ability, hull

摘要： 利用19个核质互作型不育系和9个恢复系，配制了109个杂交组合。花后35 d收获种子，分别检测每个杂交组合F1及其亲本种子在不剥壳和剥壳情况下的休眠指数。采用5×5 NCⅡ遗传设计配制了25个组合，利用其种子的休眠指数分析了配合力。结果表明，在不剥壳情况下，F1种子的休眠指数与双亲种子的休眠指数以及中亲值呈极显著正相关。109个组合中，82个组合超过中亲值，43个组合超过高亲值，具有明显的中亲优势。去除稃壳的双亲及F1种子的休眠指数均大幅度下降，表明稃壳对种子休眠性具有重要作用，但剥壳后双亲种子和F1种子休眠性之间的关系，仍然存在与不剥壳时相似的趋势。稃壳对种子休眠性的影响主要取决于F1的基因型，而不受控于母体稃壳本身。不育系、恢复系休眠性的一般配合力方差和组合的特殊配合力方差占总遗传方差的比例分别为59.2%、31.1%和9.7%，三者均达到极显著水平，说明基因的加性作用占主导地位。不育系Ⅱ112A 种子休眠性的一般配合力最高，D62A次之；恢复系以IR112一般配合力最高，2786次之。它们是选配强休眠杂交组合的优良亲本材料。

关键词: 杂交水稻, 休眠性, 多元回归, 一般配合力, 特殊配合力, 谷壳