普通小麦小穗粒数性状全基因组关联分析

Genome-Wide Association Study of Grain Number per Spikelet in Bread Wheat

为发掘小麦小穗粒数相关基因位点,以384个重要小麦品种(系)组成的自然群体为材料,利用3个环境获得的表型和55K SNP芯片分型数据进行全基因组关联分析。结果发现,142个SNP和小穗粒数显著关联,解释的表型变异范围为3.27%~6.09%。有8个SNP在2或3个环境下与小穗粒数显著关联,其中AX-109986855、AX-109875224和AX-109843323位于2D染色体523.12~526.25 Mb区段,AX-111054388和AX-110671159在2B染色体上物理距离仅0.62 Mb。这8个SNP位点中,每个SNP的2个等位变异在3个环境的小穗粒数均达到显著水平(P<0.01),例如,2D染色体上AX-109843323位点G/G等位变异在3个环境的平均小穗粒数分别比C/C等位变异增加0.32、0.37和0.39粒。8个SNP位点的优异等位变异在供试材料的分布比例为5.20%~76.80%,其中7个优异等位变异的分布频率低于45.00%。进一步分析小穗粒数优异等位变异对穗粒数的影响,发现8个SNP位点具有优异等位变异的材料穗粒数(48.45~53.61粒)明显高于具有非优异等位变异材料的穗粒数(45.04~47.37粒),而且材料聚合的优异等位变异数与其小穗粒数和穗粒数呈极显著正相关(相关系数分别为0.97和0.94,P<0.0002),表明这些小穗粒数相关位点可用于小麦穗粒数的遗传改良。

In order to explore genetic loci that associated with grain number per spikelet in bread wheat(Triticum aestivum L.),a genome-wide association study was conducted using the wheat 55K genotyping assay in a diverse panel of 384 wheat genotypes.Field trials for grain number per spikelet were conducted in one location for three consecutive years.A total of 142 significant SNPs were detected for grain number per spikelet,each of which contributed the phenotypic variation from 3.27%to 6.09%.Of these,eight SNPs were detected in two or three environments.Three SNPs(AX-109986855,AX-109875224 and AX-109843323)were located on the 523.12~526.25 Mb on chromosome 2D,and the physical distance between two SNPs(AX-111054388 and AX-110671159)was only 0.62 Mb on chromosome 2B.Significant differences for grain number per spikelet grouped by superior and inferior alleles in an SNP were detected(P<0.01)across the three environments in each of these eight SNPs.For example,cultivars carrying the G/G allele at AX-109843323 on chromosome 2D resulted in an increase of 0.32,0.37 and 0.39 grains per spikelet than that of cultivars with the C/C allele in the three environments,respectively.The percentages of cultivars carrying each of the superior alleles at the eight SNPs were varied from 5.20%to 76.80%.Seven superior alleles were present with a percentage of less than 45.00%in the accessions.Furthermore,the grain number per spike in these cultivars with superior alleles(ranging from 48.45 to 53.61)among the eight SNPs were higher than that of cultivars without superior alleles(ranging from 45.04 to 47.37).Significant association in the number of favorable alleles to grain number per spikelet and grain number per spike were observed(r=0.97 and 0.94,respectively,P<0.0002).These loci associated with grain number per spikelet are useful for improving grain numbers per spike in wheat.