基于GBS技术构建四倍体杂交冰草超高密度遗传连锁图谱

冰草是优良的牧草，也是小麦等麦类作物抗逆遗传改良的重要基因库。构建冰草超高密度遗传连锁图谱，有利于冰草的标记辅助育种和遗传分析。本研究利用基因分型测序（GBS）技术，对四倍体杂交冰草F₂分离群体的115个单株及其亲本蒙古冰草和航道冰草进行高通量SNP基因分型，经测序获得了超过584 Gb的数据，SNP鉴定以及完整度和偏分离过滤后，最终得到了5 035个高质量的SNP标记；采用Join Map 4.0作图软件构建四倍体冰草超高密度遗传连锁图谱，该遗传图谱包括14个连锁群，各连锁群的长度范围在68.959～280.309 cM之间，平均长度为153.473 cM，覆盖的基因组总长度为  2 148.621 cM，标记间的平均距离为0.427 cM。该图谱是目前冰草中分子标记数目最多、密度最高的遗传连锁图谱，为进一步开展冰草品质、抗性等重要性状的QTL定位、图位克隆及分子标记辅助育种研究等奠定了基础。

Construction of Ultra-High Density Genetic Linkage Map for Tetraploid Hybrid Crested Wheatgrass Based on GBS Technology

Agropyron is an excellent forage and an important gene pool for genetic improvement for Triticeae crops such as wheat.Construction of ultra-high density genetic linkage map can promote molecular marker-assisted breeding and genetic analysis of Agropyron,the genomic DNA extracted from 115 F₂ individuals of tetraploid crested wheatgrass and their parents(A.mongolicum Keng × A.cristatum cv. Fairway) were used for high-throughput single nucleotide polymorphism(SNP) genotyping based on genotyping-by-sequencing(GBS) technology. More than 584 Gb of data were obtained through sequencing. After SNP identification,filtration of integrity and partial segregation,a total of 5 035 high-quality SNP molecular markers were detected,which were used to construct an ultra-high density genetic linkage map of tetraploid crested wheatgrass containing 14 linkage groups by Join Map 4.0 mapping software. The entire linkage covered a total genome length of 2 148.621 cM,and the length of each linkage group ranged from 68.959 cM to 280.309 cM of the 14 linkage groups,with the average length of 153.473 cM and an average distance of 0.427 cM between adjacent markers. Compared with the genetic linkage maps of wheatgrass published previously,it is a map with the largest number of molecular markers and the highest density at present,which will serve as a foundation for further research on QTL mapping,map-based cloning,and molecular marker-assisted breeding of important traits such as quality and resistance.