利用 SSR 分子标记构建四倍体杂交冰草的遗传连锁图谱

为构建四倍体杂交冰草分子遗传连锁图谱,对深入开展冰草产量、抗性等重要性状的QTL定位及分子标记辅助育种提供依据,以四倍体杂种F2分离群体的347个单株及亲本蒙古冰草和航道冰草为材料,采用SSR分子标记技术和Joinmap 4.0软件进行了遗传作图研究。试验从256对SSR引物中筛选出条带清晰稳定、多态性丰富的适宜引物30对,PCR扩增得到224个SSR标记位点,平均每对引物扩增出7.47个位点,其中多态性标记位点185个,占82.6%。偏分离分析显示,在185个SSR多态性标记位点中有24个标记产生偏分离,占13.0%,符合植物遗传作图时通常偏分离标记比率30%的要求,可用于遗传作图。构建了1张四倍体杂交冰草的分子遗传连锁框架图谱,该图谱包含14个连锁群、185个标记,其长度范围在123.0~202.6cM之间,连锁群LG4最长、LG12最短,各连锁群的平均长度167.32cM,覆盖基因组总长度2342.5cM,标记间的平均距离12.66cM。

Construction of a genetic linkage map for tetraploid hybrid wheatgrass using a SSR molecular marker

To establish a genetic linkage map in tetraploid hybrid wheatgrass genetic mapping was conducted u-sing a simple sequence repeats (SSR)molecular marker technique with ‘Joinmap’4.0 software.347 individu-als from the F2 segregating population and their parents were utilized,this helped lay the foundation for further study of marker-assisted breeding,and quantitative trait locus (QTL)location of important traits in wheat-grass,such as disease resistance and yield.Thirty optimal primers with clear,stable and high polymorphic bands were screened from 256 tested SSR primers.A total of 224 SSR loci were obtained from polymerase chain reaction (PCR)amplification with an average of 7.47 loci per primer,of which 185 were polymorphic lo-ci,accounting for 82.6% of all loci.Segregation distortion analysis showed that a total of 24 loci were distort-ed,accounted for 13.0% of all (185)polymorphic loci,which met the requirement of <30% segregation dis-tortion for plant genetic mapping.These polymorphic loci would be useful for genetic mapping.In this study, a molecular genetic linkage map of tetraploid hybrid wheatgrass was constructed which contained 185 loci and 14 linkage groups with length ranging from 123.0 to 202.6 cM.The longest and the shortest linkage group were LG4 and LG12,respectively.The average length of each linkage group was 167.32 cM,total length of the genome was 2342.5 cM and the average marker distance was 12.66 cM.