9311背景的越光染色体片段置换系群体的构建及籼稻食味分子设计育种研究

Indica rice has larger planting area for its high yield potential. However, Japonica rice has better eating quality. The development of Indica rice variety combined with high yield and good eating quality from Japonica rice is not only a worth engaging scientific research, but also is promising for further practical application. In the present research, by successive backcrossing combined with molecular marker-assisted selection, a whole-genome coverage chromosome segment substitution line pool will be constructed using the Indica variety 9311 as receptor and the famous Japanese Japonica variety Koshihikari as donor; Based on the abundant polymorphism between the two sub-species, a high-density genetic map will be constructed and QTLs related to eating quality will be identified; The QTLs controlling the eating quality traits will be further fine mapped by the construction of the secondary mapping population and these QTLs will be dissected with the help of the available genome sequence information of 9311; The genetic effects of each QTL and the interaction effects between (among) different QTLs will be evaluated. By the phenotype prediction of different genotype combinations, the ideal genotypes coping with the breeding targets will be identified. The molecular breeding by design strategy for improving the eating quality of Indica rice will be facilitated.

籼稻种植范围广，但粳米的食味品质更佳，如何让籼稻具有粳米的食味既是一个重要的科学问题，又具有广阔的应用前景。本研究以我国代表性籼稻品种9311为受体、日本著名粳稻品种越光为供体，通过杂交和连续回交，结合分子标记辅助选择，建立覆盖9311全基因组的越光染色体片段置换系库；依据籼粳亚种间丰富的序列多态性，建立高密度的遗传图谱，鉴定稻米食味QTLs；进一步构建食味QTLs次级群体，将目的片段再分割成长度更短的片段，并借助9311序列信息，精细定位控制食味的QTLs；分析各个QTL的遗传效应，以及QTL之间的互作，模拟预测各种可能基因型的表现型，从中选择符合特定育种目标的基因型，在此基础上制定籼稻9311携有越光优良食味的分子设计育种方案。

以籼稻品种9311为受体亲本，粳稻品种越光为供体亲本，通过杂交和连续回交，结合分子标记辅助选择，建立了9311为背景的越光染色体片段置换系（CSSLs）库；通过全基因组分子标记基因型检测，获得一套覆盖全基因组的CSSLs138个。稻米淀粉黏滞性（RVA）能区分表观直链淀粉含量相似的水稻品种的食味品质优劣，对于研究控制稻米食味品质的遗传基础具有重要意义。利用构建的138个CSSLs对精米粉RVA谱7个特征值（峰值黏度、热浆黏度、冷胶黏度、崩解值、消减值、回复值及起始糊化温度）进行QTL定位。通过单因素方差分析和Dunnett多重比较，分析置换系群体与受体亲本之间相关RVA特征值的差异，选择检测到的显著差异位点作为稳定表达的QTL。一共定位10个控制RVA特征值的QTL，分布在第1、2、3、4、5和9染色体上。其中qHPV-2位于第2染色体RM341与RM525标记之间，qBDV-2位于第2染色体RM341与RM1385标记之间，可能第2染色体上与支链淀粉合成有关的两个基因与RVA谱特征值有密切关系。