从携带S5n基因的水稻种质中发掘San、Sbn和Scn基因

花粉不育是籼粳杂种F₁优势利用的主要障碍之一。包括S_a、S_b和S_c等至少6个基因座位内的等位基因互作会引起花粉不育，这些座位上的中性等位基因可以克服不育性。所以，发掘和利用中性等位基因具有重要意义。本文用携带S₅ⁿ的水稻种质，分别与台中65及其携带花粉不育基因的一套近等基因系杂交，组配具有单个座位互作和多个座位同时互作的杂种F₁，首先通过观察杂种F₁的花粉育性并比较相应杂种F₁育性的差异，初步判断是否具有中性等位基因，然后，采用与S_a、S_b和S_c座位紧密连锁的分子标记对F₂植株基因型的分离进行检测，并分析其分离比例的符合度，确定存在中性等位基因的真实性。结果发现在所鉴定的6份材料中有2份(灰背子和Madhukar)同时携带S_aⁿ和S_bⁿ，3份(饭毫皮、秕五升和粤泰B)携带S_bⁿ，1份(Jackson)携带S_cⁿ。这些材料同时携带可克服杂种F₁胚囊不育和花粉不育的基因，是克服籼粳杂种F₁不育性的重要基因来源。

Excavation of Neutral Alleles San, Sbn, and Scn from the Rice Germplasm Harboring S5n Gene

One of the principal barriers in utilization of heterosis between indica and japonica subspecies of Asian cultivated rice is F₁ pollen sterility. According to the “specific compatibility gene” theory, there are at least six loci, which cause indica and japonica hybrid pollen sterility. Excavation and utilization of neutral alleles for overcoming F₁ hybrid sterility have great importance in hybrid breeding. Varieties carrying S₅ⁿ gene were used to cross with Taichung 65 and its near isogenic lines (NILs) to produce F₁ hybrids with single-locus interaction, double-loci interaction and triple-loci interaction. Pollen fertility and seed setting rate of these hybrids were observed in F₁ to pre-judge the existence of neutral alleles and then F₂generation was genotyped with molecular markers tightly linked to S_a, S_b and S_cloci to verify the presence of S_aⁿ, S_bⁿ and S_cⁿ by detecting segregation ratio. The results showed that two materials (Huibeizi and Madhukar) carried S_aⁿ and S_bⁿ, three materials (Fanhaopi, Biwusheng and YuetaiB) carried S_bⁿ and one material (Jackson) carried S_cⁿ. These materials have wide compatibility and neutral alleles are important germplasm for hybrid breeding and knowing the molecular mechanisms underlying hybrid male sterility.