Background

Wild-abortive cytoplasmic male sterility (CMS-WA) and Honglian CMS (CMS-HL) are the two main CMS types utilized in production of three-line hybrid rice in xian/indica (XI) rice. Dissection of the genetic basis of fertility restoration of CMS-WA and CMS-HL in the core germplasm population would provide valuable gene and material resources for development of three-line hybrid combinations.

Results

In this study, two F₁ populations with CMS-WA and CMS-HL background respectively were developed using 337 XI and aus accessions being paternal parents. Genome-wide association studies on three fertility-related traits of the two populations for two consecutive years revealed that both fertility restoration of CMS-WA and CMS-HL were controlled by a major locus and several minor loci respectively. The major locus for fertility restoration of CMS-WA was co-located with Rf4, and that for fertility restoration of CMS-HL was co-located with Rf5, which are cloned major restorer of fertility (Rf) genes. Furthermore, haplotype analysis of Rf4, Rf5 and Rf6, the three cloned major Rf genes, were conducted using the 337 paternal accessions. Four main haplotypes were identified for Rf4, and displayed different subgroup preferences. Two main haplotypes were identified for Rf5, and the functional type was carried by the majority of paternal accessions. In addition, eight haplotypes were identified for Rf6.

Conclusions

Haplotype analysis of three Rf genes, Rf4, Rf5 and Rf6, could provide valuable sequence variations that can be utilized in marker-aided selection of corresponding genes in rice breeding. Meanwhile, fertility evaluation of 337 accessions under the background of CMS could provide material resources for development of maintainer lines and restorers.

中文翻译：

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全基因组关联研究揭示了水稻（/稻/ in稻和澳种）CMS-WA和CMS-HL育性恢复的遗传基础

背景

野生败型细胞质雄性不育（CMS-WA）和宏联CMS（CMS-HL）是在生产的三系杂交稻使用的两种主要类型的CMS仙/籼稻（XI）水稻。在核心种质群体中解剖CMS-WA和CMS-HL的育性恢复的遗传基础将为开发三系杂交组合提供有价值的基因和物质资源。

结果

在这项研究中，使用337 XI和aus亲本作为亲本，分别开发了两个具有CMS-WA和CMS-HL背景的F ₁种群。连续两年对这两个种群的三个与生育相关的性状的全基因组关联研究表明，CMS-WA和CMS-HL的生育恢复分别受一个主要基因座和几个次要基因座的控制。为CMS-WA的育性恢复的主要基因座共同位于Rf4表示，并且对于CMS-HL的育性恢复共同位于RF5，其被克隆主要的育性恢复（RF）的基因。此外，Rf4的单倍型分析，RF5和RF6，三个克隆的主要RF基因，分别使用337个父本种质进行。确定了Rf4的四个主要单倍型，并显示了不同的亚组偏好。Rf5鉴定出两种主要的单倍型，而功能型则由大多数父本种系所携带。此外，确定了Rf6的八种单倍型。

结论

三种单倍型分析的RF基因，Rf4表示，RF5和RF6，可以提供一种可以在在水稻育种相应基因的标记辅助选择来利用宝贵的序列变异。同时，以CMS为背景的337份种质的生育力评价，可以为维持系和恢复系的开发提供物质资源。