籼粳杂种F_1结实率稳定性研究

Studies on Seed Setting Percentage Stability in F_1 Hybrids between Indica and Japonica Rice Varieties

以品种间Ｆ１为对照，观察籼粳交杂种Ｆ１在不同播期下的结实率。结果表明：由于广亲和基因的作用，籼粳杂种Ｆ１的结实率可达７０％以上，但６７％的Ｆ１结实率对环境敏感，９月中旬抽穗的亚优２号等出现高度不育，结实率仅为１０％左右，而同期的汕优６３等品种间杂种结实率仍达８０％以上。籼粳杂种Ｆ１结实率的稳定性在组合间差异很大，０２４２８／特青等５个组合稳定性较好。结实率的稳定性与亲本选择有关，０２４２８等与中国籼稻杂交的Ｆ１比与东南亚籼稻杂交的Ｆ１结实率稳定，带有粳稻血缘的培矮６４Ｓ等与粳型广亲和系配制的Ｆ１具有较好的稳定性。正反交对结实率的稳定性表现没有影响，籼粳杂种的花粉育性对环境敏感是导致结实率不稳定的主要原因。

Based on the study and use of the wide compatibility gene(S5n), some Indic-Japonica hybrids, such as Yayou 2, have been used in rice production in recent years. However, the seed setting percentage of these hybrids appeared unstable in various degrees, which weekened the het erosis of hybrids. In this experiment, some Japonica varieties with S5n were collected and crossed with Indica varieties. The seed setting percentages of hybrids with different seeding dates were observed. The results showed that the seed setting percentages of all hybrids could come to 70% and more. 67% of the hybrids appeared sensitive to the environment. Some hybrids, such as Yayou 2,heading in the second ten-day of September, appeared highly sterile, while all intervarietal hybrids had normal seed setting percentage. Compared with Indica varieties from southeast Asia, those from China showed more stable hybrid seed setting percentage as crossed with 02428, a Japonica variety with S5, and its derivative lines. The hybrids of Indica varieties having some affinity with Japonica, such as Peiai 64S, had good stability of seed setting. The sensitivity of pollen fertility of Indica-Japonica hybrids to the environment resulted in the unstability of seed setting percentage.