白桦AFLP遗传连锁图谱的构建

以80个中国白桦(Betula platyphylla Suk)×欧洲白桦(Betula pendula Roth)的F1个体为作图群体, 利用扩增片段长度多态性(Amplified fragment length polymorphism, AFLP)标记, 按照拟测交作图策略, 分别构建了中国白桦和欧洲白桦的分子标记遗传连锁图谱。从64对AFLP引物组合中筛选出34对多态性丰富的引物组合, 这些入选的引物组合在分离群体中共检测到451个多态性位点。χ2检验结果表明, 有362个位点符合1∶1分离(拟测交分离位点), 41个位点符合3∶1分离, 20个位点符合1∶3分离, 28个位点属偏分离位点。在符合拟测交分离的位点中, 201个位点来自中国白桦, 161个位点来自欧洲白桦。利用2点连锁分析, 来自中国白桦的201个标记构成了14个连锁群(4个以上标记), 10个三连体和14个连锁对, 45个为非连锁位点, 连锁标记覆盖的总图距为1 296.1 cM, 平均图距15.5 cM。而来自欧洲白桦的161个标记构成了17个不同的连锁群(4个以上标记), 8个三连体和4个连锁对, 15个为非连锁位点, 连锁标记覆盖的总图距为1 035.8 cM, 平均图距12 cM。

Construction of genetic linkage maps of silver birch based on AFLP markers

Based on the inheritance and segregation of amplified fragment length polymorphism (AFLP) markers, the first middensity linkage map for silver birch was constructed using a pseudotestcross mapping strategy. A segregating popula-tion including 80 progenies from the cross between Betula platyphylla Suk and B. pendula Roth was obtained. A set of 64 primer combinations were screened, and 34 pair primer combinations were selected to generate AFLP markers within a sample of 80 F₁ progenies. A total of 451 segregating sites were identified. Among them, 362 belonged to 1:1 segregating site, and 41 belonged to 3:1 segregating site, 20 belonged to 1:3 segregating site, and others were found distorted from the Mondelian ratio. Altogether 362 sites segregating 1:1 (testcross configuration) were used to construct parent-specific link-age maps, 201 for B. platyphylla and 161 for B. pendula. One linkage maps resulted consisted of 201 marker sites in 14 groups with four or more sites per group, 10 triples and 14 pairs for B. platyphylla, which covered a map distance about 1 296.1 cM (Kosambi units), and the average map distance between adjacent markers was 15.5 cM. Another linkage maps resulted consisted of 161 marker site for B. pendula were mapped onto 17 groups with four or more sites per group, 8 triples and 4 pairs, which covered a map distance about 1 035.8 cM, and the average map distance between adjacent markers was 12 cM. Those maps can be used in QTL analysis and molecular assistant selection in birch breeding.