亲本籼粳成分与两系杂交粳稻杂种优势的关系及遗传基础

以籼粳重组自交系(秋光×七山占，RILs)和粳型光温敏核不育系(GB028S)及其杂交F₁为材料，利用程氏指数法和分子标记法分析亲本的籼粳成分与杂种优势的关系及遗传基础。结果表明，采用程氏指数法和分子标记法在群体籼粳分类的结果上比较一致；RILs偏粳系数与F₁产量及其杂种优势均呈显著或极显著的二次曲线关系；F₁产量在偏粳系数0.55~0.70区间内出现高峰值，杂种优势在偏粳系数0.50~0.65区间内出现高峰值，即RILs偏粳系数为0.55~0.65时F₁有形成较高产量及杂种优势的潜力。Chr.8、Chr.11和Chr.12的籼粳成分与F₁产量及杂种优势关系密切，双亲的遗传距离与F₁产量和相关性状及杂种优势没有明显的关系。

Relationship between Indica-Japonica Index of Parents and Heterosis of Hybrid and Its Genetic Basis in Japonica Two Line Hybrid Rice

In order to further reveal the relationship between composition of subspecies lineage and heterosis in Oryza sativa L., we built a bridgefor morphological index, Cheng’s index (Chi) andmolecular index, japonica discrimination values (D_j) based on two populations, a recombinant inbred lines (RILs), derived from the cross betweenindicacultivar Qishanzhan and japonica cultivar Akihikari, and japonica photo-thermo sensitive genic male sterile(PTGMS) lineGB028S and their F₁ hybrids. Two indexs achieved relatively consistent results in two populationsindependently. Significant curvilinear relationship appeared among D_jvalues, F₁ yield and yield heterosis. The peaks of F₁ yield and yield heterosis were detected in D_jinterval from 0.55 to 0.70 and from 0.50 to 0.65 respectively, indicating that 0.55−0.65 is the preferential D_j interval for producing high yield and heterosis of F₁ hybrids. Compositions of subspecies lineage on Chr.8, Chr.11, and Chr.12 were closely related with yield and heterosis of F_1, however, the relationship among parent’s genetic distance, F₁ yield and heterosis was not significant.