A total of 66 chromosome segment substitution (CSS) lines,derived from a cross between indi-ca rice inbred line IR24 (as the recurrent parent) and japonica rice inbred line Asominori (as the donor par-ent),were used to investigate the heterotic loci in three-line rice hybrids (IAS).Each CSS line as male parent was crossed with four CMS lines Zhong 9A,Rongfeng A,1133A,1A as female parent,and the heterosis of each F1 hybrids was estimated by comparing the male parent CSSLs.Field experiments were carried out across two different environments (1133A/CSSL,1A/CSSL in 2012,Zhong 9A/CSSL,Rongfeng A/CSSL in 2013)in Nan-chang to evaluate the yield-related traits in the 65 CSS lines and each corresponding F1 hybrids.Quantitative trait loci (QTL) analyses were conducted using a likelihood ratio test based on the stepwise regression.QTL were de-tected by statistical software QTL IciMapping using mid-parental heterosis as basic phenotypic data through anew different SSR map.The LOD threshold was set at 2.0 which represented the significant effect of QTL.As a result,ninety-four heterotic loci of yield-component traits were identified with significant effects in different en-vironments.Three heterotic loci were linked closely with marker RM5474,RM336,RM287 on chromosome 3,7,11 respectively which impact panicles per plant,panicle length,seeds density,thousand-grain weight was detec-ted in four test F1 populations simultaneously.Pleiotropic effects of individual loci might be one of the genetic basis for the formation of heterosis.%拟用一套以籼型恢复系IR24为背景亲本,渗入粳稻Asominori血缘的共有65个家系的染色体片段置换系(chromosome segment substitution(CSS)lines of IR24 as recipient parent and Asominori as donor parent,简称IAS群体)为父本,以荣丰A、中9A、1133A、1A 4个籼型不育系为母本,测定与产量相关的5个农艺性状的杂种优势.利用染色体片段置换系已有的分子标记图谱和QTLIciMapping软件,采用逐步回归和极大似然估计相结合的方法,以LOD值≥2.0作为经验阈值来判断QTL是否存在来检测影响杂种优势的数量性状位点.研究结果表明,4套测交群体共检测到94个杂种优势位点,在所有检测到影响单株有效穗数,平均穗长,着粒密度,千粒质量等性状杂种优势位点中,分别位于第3,7和11染色体上的分子标记RM5474,RM336,RM287能够在4套测交群体中检测到,表现出一因多效现象,因此认为,QTL的一因多效可能也是杂种优势形成的遗传基础之一.
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