不同生态环境下籽粒大小相关性状QTL定位

QTL Mapping of Seed Size Traits under Different Environment in Rice

为了揭示不同环境下籽粒大小性状的分子遗传基础,鉴定新的调控籽粒大小相关的基因,为培育适宜籽粒大小的高产优质品种提供新的基因"元件"。以龙稻5(Longdao 5,LD5)和中优早8(Zhongyouzao 8,ZYZ8)杂交衍生的重组自交系(Recombinant inbred lines,RILs)群体为试验材料,采用QTL Ici Mapping v4.0软件基于完备复合区间作图法在不同生态环境下(沈阳,2015;南昌,2016年;海南,2016年)对籽粒大小性状进行QTL分析。在3种环境条件下,龙稻5和中优早8的籽粒大小性状均存在显著差异,在RILs群体中,籽粒大小性状存在较大幅度变异,呈现双向超亲分离,近似于正态分布,这表明籽粒大小性状均为多基因控制的数量性状;不同环境下共检测到35个控制籽粒大小性状相关的QTL,分布于第2,3,4,5,8,10和11号染色体上,单一QTL解释5.76%~38.88%表型变异;4个QTL能在3个环境下稳定表达,分别为q ST8、q SL11、q SV11和q TGW11,7个QTL能在2个环境下被检测到,分别为q SV2b、q ST3、q SLW3、q SLW8、q TGW8、q SW8和q SV8。此外,籽粒大小相关的QTL成簇分布于第2,3,8和11号染色体上,位于第8和11号染色体上检测到的2个QTL簇q SS8(q SW8、q ST8、q SLW8、q SV8和q TGW8)和q SS11(q SL11、q SV11和q TGW11)存在明显的多效性和环境钝感特性,对籽粒大小具有明显的调控作用,其中q SS8可能是一个新的位点。结果对进一步发掘和利用新的水稻籽粒大小相关的QTL具有重要意义。

To reveal the genetic basis of seed size traits,identification of novel QTL related to grain size under different environments,which is important to provide us with useful information for marker-assisted improvement of the higher yield and quality in rice.A recombinant inbred lines(RILs)derived from the cross between Longdao 5(Japonica)and Zhongyouzao 8(Indica)was used to identify QTLs for seed size under multi-environments(Shenyang,2015;Nanchang,2016;Hainan,2016),QTLs were mapped by QTL IciMapping v4.0 software,using ICIM method for seed size traits.Analysis of variance test showed that a significant difference was detected between the parents under three different conditions.A normal distribution of phenotypic values for seed size traits were observed,which indicated that seed size traits were controlled by multiple genes.Thirty-five QTLs for seed size were detected on the chromosome 2,3,4,5,8,10 and 11 under three different environments,the range of individually explaining phenotypic variation from 5.76%to 38.88%,eleven were stable expression across two or three environments,qST8,qSL11,qSV11 and qTGW11 were detected under three environments,qSV2b,qST3,qSLW3,qSLW8,qTGW8,qSW8 and qSV8 were detected under two environments,respectively.These QTLs clustered on the chromosome 2,3,8 and 11,which these QTLs cluster qSS8(qSW8,qST8,qSLW8,qSV8 and qTGW8)and qSS11(qSL11,qSV11 and qTGW11)were located on the chromosome 8 and 11 with pleiotropic genetic overlap effect and stable expression,which a novel major QTL qSS8 and these research results have an obvious effects on seed size with the significant value of theoretical and breeding practice.