两个水稻骨干恢复系重要农艺性状的遗传基础研究

水稻骨干恢复系是指在杂交稻育种中广泛应用的一类恢复系。探明骨干恢复系的遗传基础,发掘其重要农艺性状基因/QTL,对分子标记辅助选择水稻恢复系育种具有重要应用价值。本研究以生产上广泛应用的三系骨干恢复系成恢727和两系骨干恢复系9311为亲本,培育了具有250个系的重组自交系群体。分别在2015年三亚和2016年合肥两个环境下进行了9个重要农艺性状表型和SSR分子标记基因型鉴定,用SAS9.2分析表型数据,用QTL Ici Mapping v4.1进行QTL定位分析。在三亚和合肥两个环境下共检测到39个QTL,三亚检测到16个,分布于第1、2、4、7、8、10、11和12染色体上;合肥检测24个,分布于第1、2、3、7、8、9、10和12染色体上。其中qPH1-1在三亚和合肥两个环境下都能检测到,加性效应分别为-1.75和-2.46。在检测到的39个QTL中,有24个QTL的增效等位基因来自恢复系成恢727,15个QTL的增效等位基因来自9311。共计有26个QTL曾被前人定位,13个属于尚未见文献报道的新QTL。另外,在RM279~RM521、RM336~RM3534、RM25~RM547、RM553~RM160、RM222~RM271区段内检测到5个多效性QTL位点。其中RM25~RM547位点与已经克隆的基因Ghd8位置相近。RM553~RM160位点是一个新的多效性位点,分别控制每穗实粒数、单株产量和结实率,而且效应和表型变异贡献率都较大。其余3个位点在前人的研究中分别有所报道,但其多效性则是在本研究中首次发现。在本研究新发掘到的QTL中,控制穗数的QTL qPN12-1,控制穗长的QTL qPL1-2和qPL10-1,控制总粒数的QTL qSNP2-1和qSNP10-1,控制结实率的QTL qSF3-1,控制千粒重QTL qTGW7-1和控制产量的QTL qGY1-1效应均比较大,解释的表型遗传变异比例也较高。本研究的结果将会为相关性状QTL的精细定位、克隆和育种应用奠定基础。

Study on the Genetic Basis of Important Agronomic Traits in Core Restorer Lines of Rice (Oryza Sativa L.)

The main restorer line is a kind of restorer lines which has been widely used in hybrid rice breeding practice.The study on the genetic basis of main restorer lines and identification of quantitative trait loci (QTL) or gene underlying important agronomic traits will facilitate the restorer development by the molecular marker assisted selection in rice.In this study,the population with 250 recombinant inbred lines (RIL)was developed with a threeline main restorer Chenghui 727 and a two-line restorer 9311 as parents,both of which have been widely used in hybrid rice breeding.The evaluation of 9 important agronomic traits and genotypic analysis of SSR markers were conducted in Sanya,Hainan of 2015 and Hefei,Anhui of 2016.The phenotype data was analyzed by SAS9.2 QTLs were mapped and analyzed by QTL IciMapping v4.1 software.A total of 39 QTLs were detected in two environments,among which 16 QTLs were identified in Sanya and located on the chromosome 1,2,4,7,8,10,11 and 12,and 24 QTLs were identified in Hefei and located on the chromosome 1,2,3,7,8,9,10 and 12.The qPH1-1was detected in both Sanya and Hefei,with the additive effects were-1.75 and-2.46 respectively.The increasing alleles of 13 QTLs come from Chenghui 727 and 16 QTLs from 9311.There are 26 QTLs identified here had been reported by the previous study and 13 QTLs were newly detected in this study.In addition,5 pleiotropic QTLs were found in the intervals of RM279-RM521,RM336-RM3534,RM25-RM547,RM553-RM160 and RM222-RM271.Among which the interval of RM25-RM547 was near the cloned gene Ghd8.The QTL located in RM553-RM160 was a novel pleiotropic QTL underlying the filled grain number per plant,grain yield per plant and spikelet fertility with large addivite effects and contributed more than 5 ％ of the phenotypic variation.The other three pheiotropic QTLs had been reported in previous study as a single QTL,however the pleiotropism was found in this study only.In present study,all the newly found QTL e.g.qPN12-1 underlying panicle number,QTL qPL1-2 and qPL10-1 underlying panicle length,QTL qSNP2-1 and qSNP10-1 underlying spikelet number per panicle,qSF3-1 underlying spikelet fertility rate,QTL qTGW7-1 under.lying grain weight and qGY1-1 underlying grain yield have large additive effects and explained high proportion of phenotypic variation.The results in this study will be helpful to the fine mapping,cloning and breeding for the related traits.