大白菜回交导入系群体构建及其遗传分析

The Development of Backcross Introgression Lines (BILs) and Genetic Analysis for Brassica campestris

利用大白菜栽培品种的DH系Z16和白菜型油菜自交系L144杂交的F1获得包括119个株系的DH群体。用相同亲本的F1与Z16进行独立回交,利用25个独立回交的BC2分别得到这些株系的DH系,选择每个BC2的4～6个DH系构建121个株系的BIL群体。进一步利用SSR和SRAP标记构建了DH群体遗传图谱,由10个连锁群组成,包括245个分子标记,总长度714cM,平均遗传图距2.9cM。再以此图谱为参照,用锚定在染色体上的97个SSR标记研究供体亲本L144的染色体片段在BIL群体中覆盖基因组比率。在BIL群体中来源于L144的基因组片段占0.84%～35.00%,平均为11.31%,接近理论遗传预期值12.50%。在25个BC的BIL株系中供体亲本L144等位位点占1.69%～27.36%,平均为11.03%。

This paper reported the genetic structure analysis for a backcross introgression lines （BILs） of Brassica campestris L. based on a genetic linkage map constructed using a doubled haploid （DH） population. the BILs population with 121 lines derived from a cross between a DH line of a commercial F1 （ Z16 ） and an oil-type B. campestris inbred line （L144） , which was developed by twice consecutively backcrossing using Z16 as a reeipient parent. The characteristics of introgression of L144 in BILs was analyzed using 97 SSR markers mapped on the DH genetic map. The results showed that the variation of percentage of the donor parent （L144） genome presenting in the BILs was from 0. 84% to 35.00% , with an average of 11.31% , consistent with the theoretical expectation of 12.50%. The percentage of the donor parent （L144） alleles presenting in the 25 BC2 of BIL plants ranged from 1.69% to 27.36% , and the average ratio was 11.03%.