基于55K SNP芯片的小麦籽粒主要品质性状的全基因组关联分析

Genome-wide association study of major grain quality traits in wheat based on 55K SNP arrays

通过检测118份小麦材料3个环境下吸水率、蛋白质含量、容重、湿面筋含量、面团稳定时间、面团形成时间、沉降值和出粉率8个小麦籽粒品质的表型值,结合小麦55K SNP芯片分析基因型,采用Q+K混合模型进行全基因组关联分析。在不同环境下, 8个籽粒品质性状均具有广泛变异,其中沉降值的变异系数最大为16.47%~17.03%,各品质性状遗传力为0.71~0.85。118份小麦材料被分为3个亚群,亚群Ⅰ包括41(34.75%)份,安徽供试材料占绝大部分;亚群Ⅱ包括32 (27.12%)份,是以安徽、江苏、四川为主体的群体;亚群III包括45 (38.13%)份,主要为安徽及江苏省份材料。22个与小麦籽粒品质性状显著关联的稳定位点(P<0.001)在2个及以上的环境中被重复检测到,分布于染色体1B (4)、1D (1)、2B (1)、2D (1)、3B (2)、3D (1)、4D (1)、5A (1)、5B (1)、5D (3)、6B (2)、7B (3)和7D (1),解释了8.53%~16.32%的表型变异。稳定位点中包含3个一因多效显著关联位点, 14个可能控制小麦品质性状的新遗传位点,并筛选出11个可能与小麦籽粒品质性状相关的候选基因;有利等位基因的数量越多,品质性状表型值越高,并发现了在8个主要品质性状均携带有利等位基因的载体材料,其中,华成859和济麦44包含最多的有利等位基因,可供改良小麦品质的育种亲本使用。本研究结果为小麦优良品质小麦培育提供了理论依据、亲本材料和分子标记。

To meet people's demand for wheat quality,exploring relevant candidate genes can provide a theoretical basis for genetic improvement and molecular marker-assisted selection of high-quality wheat cultivars.In this study,phenotypic values of eight wheat grain quality traits,including water absorption,grain protein content,volume weight,wet gluten content,dough stability time,dough development time,sedimentation value,and flour yield,were detected in 118 wheat genotypes in three environments.The genotypes were analyzed using 55K SNP arrays,and a genome-wide association study was conducted using the Q+K mixed model.In three different environments,the eight grain quality traits had extensive variation,the maximum variation coefficient of sedimentation value was 16.47%-17.03%,and the heritability of each quality trait was 0.71-0.85.The 118 wheat genotypes were divided into three subgroups:subgroup I,consisting of 41(34.75%)genotypes,mainly from Anhui;subgroup II,consisting of 32(27.12%)genotypes,predominantly from Anhui,Jiangsu,and Sichuan provinces;and subgroup III,consisting of 45(38.13%)genotypes,mainly from Anhui and Jiangsu provinces.22 stable loci significantly associated with wheat grain quality traits(P<0.001)were repeatedly detected in two or three environments,distributed on chromosomes 1B(4),1D(1),2B(1),2D(1),3B(2),3D(1),4D(1),5A(1),5B(1),5D(3),6B(2),7B(3),and 7D(1),explaining 8.53%to 16.32%of the phenotypic variation.Among the stable loci,three exhibited significant pleiotropic effects,14 were identified as novel loci for controlling wheat quality traits,and 11 candidate genes possibly associated with wheat grain quality traits were screened.The higher the number of favorable alleles,the higher the phenotypic values of quality traits.Furthermore,it was discovered that several genotypes carried favorable alleles for all eight major quality traits.Among them,the wheat cultivars Huacheng 859 and Jimai 44 contained the highest number of favorable alleles,making them valuable breeding parents for improving wheat quality.The results of this study provide a theoretical basis,parental materials,and molecular markers for the breeding of high-quality wheat.