水稻低温发芽力QTL定位和遗传分析

以Kinmaze(粳稻)／DV85(籼稻)的重组自交系F10世代群体检测了影响水稻低温发芽力性状的数量性状基因座(QTL)。通过测定不同时期的低温发芽率，确定了15℃低温、第10d为检测低温发芽率的最适处理温度和时间，该条件下能够充分检测到品种的差异和分离群体的变异。通过设置对照，证明所检测的低温发芽率不受休眠及二次休眠的影响。15℃低温、第10d时，Kinmaze的发芽率达35％，DV85的发芽率只有7％，两亲本之间存在明显差异，该群体81个家系的低温发芽率变幅在0％～99％之间。QTL分析结果检测到5个与低温发芽力相关的基因座，分别位于第2、6、7、11和12染色体上。位于第2、6和11染色体上的qLTG-2、qLTG-6和qLTG-11贡献率分别为27．1％、17．1％和15．0％，对低温发芽力性状的增效基因来自DV85；位于第7、12染色体上qLTG-7和qLTG-12的贡献率分别为22．9％和8．8％，增效基因来自Kinmaze。其中，qLTG-6和qLTG-11在染色体上的位置与已报道的有关低温发芽力QTL位置相似，而qLTG-2、qLTG-7和qLTG-12为新检测的低温发芽力基因座。上位性分析结果显示，第3与第5染色体上存在影响低温发芽力的互作位点，其互作可以提高低温发芽力，而第7染色体上的两位点之间的互作降低了低温发芽力。

Inheritance and QTL Mapping of Low Temperature Germinability in Rice(Oryza sativa L.)

Quantitative trait loci (QTL) controlling low temperature germinability (LTG) in rice were identified using 81 recombinant inbreed lines (RILs) derived from a cross between a japonica variety Kinmaze and an indica variety DV85.The accurate condition of LTG evaluation was assumed at 15℃ for 10 d after removing the effect of dormancy and the second dormancy.By setting check,the scores of LTG in this study were evaluated.The germination rate at 15℃ for 10 d was scored to represent the LTG.The LTG of the RILs ranged from 0 to 99%.By single point analysis,simple interval mapping,and composite interval mapping,5 putative QTL,qLTG-2,qLTG-6,qLTG-7,qLTG-11 and qLTG-12 were detected on chromosomes 2,6,7,11 and 12 respectively.At the regions of qLTG-2,qLTG-6 and qLTG-11,DV85 alleles increased the LTG,while Kinmaze alleles increased it at the regions of qLTG-7 and qLTG-12.Among the five QTLs reported here,qLTG-2,qLTG-7 and qLTG-12 were newly detected,while the other two QTL-containing regions were close to those previously reported.Epistatic QTL were also detected in this paper.