超级稻增产基因的聚合及分子设计育种利用研究

Yield trait, a complex quantitative trait, is controlled by multiple genes and environments. Molecular design breeding of ideotype super rice using increasing-yield genes is an important research direction of the breakthrough of rice yield bottleneck. In this study, based on deep resequencing RILs and SSSLs derived from some elite rice varieties Liang-You-Pei-Jiu (LYP9, Peiai64×9311), HGX74, ZH498 and Tian-You-Hua-zhan, map-based cloning strategy would be further used to isolate 2-3 high yield genes and heterosis, and to dissect the molecular mechanism and genetic network of these genes. Some key yield genes such as GL7、GS2、IPA1、DEP1、gs3、GW5、gw7、GW8 and Ghd8 via backcrossing will be introgressed into the mega rice cultivars. 9311, HGX74 and ZH498 near isogenic introgression lines containing the various target genes will be constructed. Multi-gene pyramiding lines and geno-phenotype (GP) database will be constructed too. We also analyze interaction relationship between the genes controlling the three compenents of yield (panicle number, grain number and grain weight), to elucidate the regulation patterns of yield. Using breeding value prediction program QuLine and CrossPredictor, to predict the target genotype effects under polygenes, multi-generations and in different environments, and to select the strongest gene pyramiding lines / strain and the optimum polymerization pathway of yield genes. To breed by design new-generation super rice, to enrich and develop the theory of molecular design breeding.

产量性状是受多基因和环境控制的复杂数量性状，利用增产基因分子设计培育理想株型超级稻是突破目前水稻产量瓶颈的重要方向。本项目利用水稻主栽品种（两优培九、华粳籼74、蜀恢498和天优华占等品种）衍生的遗传群体（RIL、SSSL），发掘一些具有育种利用价值的产量优异等位基因，解析产量性状形成的遗传基础及其调控网络。同时，将已克隆的增产基因GL7、GS2、IPA1、DEP1、gs3、GW5、gw7、GW8和Ghd8等基因，回交导入到主栽品种中，构建含目标基因的近等基因系和导入系文库；构建多基因聚合系的基因型-表型值（GP）数据库。在不同生态区预测多基因多世代的基因型效应值和目标基因型概论；选择最佳多基因聚合系和基因聚合途径，分子设计培育新一代超级稻，丰富和发展分子设计育种理论。

构建了6套超级稻染色体片段代换系或SSSL文库，为重要性状的分子遗传机理解析和设计育种奠定了材料基础。代换系包括主栽品种9311/培矮64、蜀恢498代换系、华粳籼74背景的SSSL文库。完善了超级稻两优培九、蜀恢498等RIL群体的全基因组信息和转录组信息，挖掘了一系列产量和品质的QTL，以及超级稻产量的遗传基础和基因辅助育种理想平台。解析了超级稻主栽品种中氮高效、产量和大穗性状的调控机理，并在育种中利用。利用9311/日本晴RIL群体克隆了ClO3-抗性的QTL，qCR2，编码NAD(P)H依赖型硝酸还原酶OsNR2，参与水稻氮同化，粳型OsNR2导入籼稻可显著增加NR活性，积累更多的NO3有机氮；多个NR基因聚合，有利于增产和农业可持续增长。还克隆了大穗QTL GN1a和粒型调控基因OsUBP15。OsUBP15能与OsDA1蛋白互作，调控粒型。利用国内外品种，挖掘了50多个IPA1、DEP1、GW5L、Gn1a、gw8、pid3/Ctb1等基因的有利等位基因和功能标记；将目标基因导入到主栽培品种，建立了6个产量相关基因的基因型-表型G-P数据库，并进行加代；利用已克隆的重要功能基因，对主推品种中的抗稻瘟病基因、产量、抗倒伏基因进行了全基因组等位性分析，并开发了分子标记，建立了水稻分子设计育种的技术平台。将系列优质、高产基因导入9311、蜀恢498、华粳籼74背景的SSSL，预测多基因型效应值，选择最佳聚合系，培育新组合。发表论文10篇，申请专利3项，培养研究生12名，品种审定6个。