黄淮麦区北片小麦穗部相关性状的全基因组关联分析

Genome-wide Association Study of Spike-related Traits of Bread Wheat in North Huanghuai River Valley Wheat Region

为了挖掘与穗部相关性状显著关联的标记位点及其优异等位变异,以黄淮麦区北片近30 a培育的132个小麦主栽品种及其衍生品系为材料,在8个环境中对穗长、总小穗数、穗粒数和穗密度等4个重要穗部相关性状进行表型鉴定,结合小麦55K SNP芯片基因分型开展标记-性状全基因组关联分析。结果表明,所检测到的121个与穗部相关性状显著关联的标记位点包括与穗长显著关联的位点38个,与总小穗数显著关联的位点15个,与穗密度显著相关的位点47个,与穗粒数显著关联的位点21个。其中,有8个显著关联位点在3个及3个以上环境中被重复检测到,包括与穗长显著关联位点AX-108730544-1D、AX-94755570-2A和AX-111703851-6D,与总小穗数显著关联的位点AX-111235532-2A和AX-110926142-2A,与穗粒数显著关联位点AX-110378404-5A,与穗密度显著关联位点AX-108730544-1D和AX-110963299-1D。对上述8个显著关联位点的地域分布进行分析,发现各个位点的优异等位基因频率在黄淮麦区不同省份品种中存在较大差异。基因聚合效应分析表明,穗长、总小穗数和穗密度表型值随优异等位基因数量增加而呈现提高的趋势。上述研究结果对小麦穗部性状优异等位基因挖掘和分子标记选择育种具有重要的参考价值。

In order to identify the significant association loci and the favorable alleles that are responsible for spike-related traits,genome-wide association study(GWAS)was conducted in this research using an association panel consisted of 132 elite wheat varieties and their advanced lines mainly from the North Huanghuai River Valley Wheat Region.Wheat 55K SNP array was used to perform marker-trait association analysis.Four spike-related traits were evaluated at 8 environments,involving spike length,total spikelet number per spike,kernel number per spike and spike compactness.A total of 121 significant association SNP loci were identified,containing 38 sites significantly associated with spike length,15 sites significantly associated with total spikelet number per spike,47 sites significantly associated with spike compactness,and 21 sites significantly associated with kernel number per spike.There were 8 SNPs detected in multiple environments,including AX-108730544-1D,AX-94755570-2A,AX-111703851-6D,AX-111235532-2A,AX-110926142-2A,AX-110378404-5A,AX-108730544-1D and AX-110963299-1D.Geographical distribution analysis indicated that frequencies of the favorable alleles at the 8 significant association loci were divergent among theprovinces in the Huanghuai River Valley Wheat Region.The pyramiding effect analysis showed that the phenotypic value of spike length,total spikelet number per spike and spike compactness were increased with incorporation of the favorable alleles.These results provide a fundamental basis for gene mining and marker-assisted selection breeding of wheat panicle traits.