利用东乡野生稻染色体片段置换系鉴定穗部性状主效QTL

Mapping Major QTLs for Panicle Traits Using CSSLs of Dongxiang Wild Rice(Oryza rufipogon Griff.)

【目的】稻穗是水稻产量的主要承载者,发掘穗部性状相关的主效QTL对进一步精细定位、克隆和育种利用具有重要意义。【方法】以粳稻日本晴为受体、东乡野生稻为供体构建的一套染色体片段置换系(chromosome segment substitution lines,CSSLs)群体为材料,在4个生态环境下进行穗部性状表型鉴定与主效QTL定位分析。【结果】不同生态环境下CSSL群体穗部性状存在较大幅度变异,东乡野生稻染色体片段的导入显著改变背景亲本的穗部性状,具有明显的增产效应;早季、中季、晚季和海南环境下共检测到64个控制每穗颖花数和籽粒大小的QTL,其中qPL2、qSN1.2、qSN2、qFGN3、qTGW2、qTGW12.1和qSL2在3个环境下稳定表达,21个QTL在2个环境下被重复检测到,其余QTL仅在单一环境下被发现;主效QTLqSN1.1、qSN1.2、qSN2、qSN3和qSN12对每穗颖花数具有明显的影响,多个QTL聚合具有明显调控每穗颖花数的功能;主效QTLqSL2、qSL3.2、qSLW3.1、qSLW3.2、qTGW8.1和qSLW10对籽粒大小具有明显的影响。这些位点分别作用于粒长、粒宽和长宽比,相互作用、共同决定籽粒大小;同时,穗部性状QTL成簇分布于10个染色体区段,其中主效QTL簇qGNS1.1、qGNS1.3、qGNS2.1、qGNS3.1、qGNS9、qGNS10和qGNS12包含多个调控每穗颖花数及籽粒大小性状的QTL,可在不同环境下稳定表达。来自东乡野生稻的等位基因具有明显调控产量表型的功能。【结论】研究结果不仅为东乡野生稻优异基因发掘奠定基础,也可为水稻穗部性状的分子育种提供新基因源。

【Objective】Panicles are the primary yield determinants in rice,making it essential to explore major QTL associated with panicle traits for subsequent fine mapping,cloning,and breeding purposes.【Method】We employed a population of Chromosome Segment Substitution Lines(CSSLs)generated by crossing Nipponbare(japonica)with C35(Dongxiang wild rice)and conducted phenotypic evaluations and major QTL mapping across four distinct ecological environments.【Result】Significant variations in panicle traits were observed in the CSSL populations across different ecological environments.The introduction of Dongxiang wild rice chromosome segments brought about substantial changes in panicle traits,leading to a noticeable increase in production.A total of 64 QTLs controlling grain number per panicle and grain size were identified across early-season,mid-season,late-season in Jiangxi,and Hainan environments.Among these QTLs,qPL2,qSN1.2,qSN2,qFGN3,qTGW2,qTGW12.1,and qSL2 consistently expressed in three environments,and 21 QTLs were detected in two environments,while others were specific to a single environment.Major QTLs,including qSN1.1,qSN1.2,qSN2,qSN3,and qSN12,exhibited significant effects on grain number per panicle,suggesting that multiple QTL aggregations play a crucial role in regulating grain number.Major QTLs such as qSL2,qSL3.2,qSLW3.1,qSLW3.2,qTGW8.1,and qSLW10 had evident effects on grain size,influencing grain length,grain width,and the length-to-width ratio.Interactions between these loci jointly determined grain size.Additionally,we observed clusters of panicle trait QTLs on 10 chromosome segments.These major QTL clusters,qGNS1.1,qGNS1.3,qGNS2.1,qGNS3.1,qGNS9,qGNS10,and qGNS12,contained several QTLs that regulated grain number and grain size traits.These clusters exhibited stable expression across diverse environments,underscoring the regulatory role of alleles from Dongxiang wild rice in enhancing yield.【Conclusion】These findings not only serve as the foundation for uncovering valuable genes in Dongxiang wild rice but also provide new genetic resources for the rice molecular breeding.