小麦SSR和SNP标记在Taichung29×白芒麦重组自交系群体中的偏分离分析

为明确小麦SSR和SNP标记在Taichung29×白芒麦重组自交系群体中的偏分离现象及产生原因,提高遗传图谱构建的质量,以我国小麦农家品种白芒麦与感病品种Taichung29杂交构建的包含181个F8代重组自交系(recombinant inbred line,RIL)为试验材料,利用筛选得到的110个SSR标记和6 859个SNPs多态性标记进行偏分离分析。结果显示,共有1 069个标记位点表现出偏分离,占标记总数的15.3%。其中,683个标记偏向于白芒麦,占偏分离标记数的63.9%;386个标记偏向于Taichung29,占偏分离标记数的36.1%。偏分离位点在染色体上分布大多数是成簇出现,有76.3%的偏分离标记形成偏分离热点区域(segregation distortion region,SDR),共检测到了74个SDR,分布在15条染色体上,其中B染色体组包含有最多的SDR,偏分离方向为白芒麦。抗病亲本白芒麦和感病亲本Taichung29的基因型在RIL群体中分布比例为1.03∶1.00,接近1∶1的理论比例,标记在RIL群体整体分离比基本平衡,显示出偏分离主要是由遗传因素引起。

Genetic analysis of segregation distortion of SNP and SSR markers in wheat RIL population from the Taichung29×Baimangmai

The analyses of segregation distortion phenomenon and reasons in the Taichung29×baimangmai recombinant inbred wheat lines by using SSR and SNP markers are helpful for improving the quality of the genetic map. By using a population consisting of 181 F₈ recombinant inbred lines (RIL) derived from a common wheat variety Taichung29 crossed by a landrace Baimangmai, segregation distortion analysis was performed with the 110 SSRs and 6859 SNPs polymorphic markers developed for the population. The results showed that a total of 1 069 marker loci showed segregation distortion, accounting for 15.3% of the total marker number of the wheat genetic maps, of which 683 markers (63.9% of the segregation distortion total markers) distributed on wheat genomes distorted to parent Baimangmai, and 386 markers (36.1% of the segregation distortion total ones) distorted to parent Taichung29. Meanwhile, segregation distortion regions usually distributed as clusters. Among the segregation distortion markers,76.3% formed segregation distortion regions (SDRs), and a total of 74 SDRs were detected, scattering on 15 chromosomes. Most SDRs lay on genome B, genetically distorted to parent Baimangmai. The distribution proportion of the resistant parent baimangmai and susceptible parent Taichung29 genotypes in RIL population was 1.03:1.00, close to the theoretical ratio of 1:1, and the overall separation ratio was basically balanced, showing that segregation was mainly caused by genetic factors.