烟草染色体片段代换系的构建与遗传评价

Construction and Genetic Evaluation of Chromosome Segment Substitution Lines in Tobacco(Nicotiana tabacum L.)

以综合性状优良的烤烟种质Y3为轮回亲本,抗烟草黑胫病（0号和1号生理小种）和赤星病的雪茄烟种质Beinhart 1000-1及优质烤烟品种K326为供体亲本,连续回交并结合分子标记辅助选择,构建国内外第一套由256个具有烤烟Y3遗传背景并渐渗有Beinhart 1000-1和K326染色体片段株系代换系群体。该群体携带377个代换片段,分布于烟草24条连锁群上。每个株系携带1~5个代换片段,代换片段长度介于0.05~36.88 c M,平均长度7.75 c M。代换片段重叠累加总长度为2922.57 c M,是烟草基因组总长度的2.61倍。代换片段覆盖总长度为1114.32 c M,烟草基因组覆盖率为99.45%。本研究构建的片段代换系可用于烟草基因定位、复杂性状的QTL分析和标记辅助选择育种。

A set of chromosome segment substitution lines（CSSLs） of tobacco（Nicotiana tabacum L.） were first developed by molecular marker assisted selection（MAS） and successive backcrossing with Y3, the flue-cured tobacco germplasm with comprehensive traits as the recipient parent, and two common tobacco cultivars Beinhart1000-1 and K326 as the donor parents. The cigar tobacco cultivar Beinhart 1000-1 carries a variety of resistance traits including black shank（race 0 and race 1） and brown spot resistance, while the flue-cured tobacco K326 is a commercial cultivar with high quality. In 256 CSSLs, a total of 377 substituted segments derived from donor Beinhart 1000-1 and K326 with genetic background of Y3 distributed on 24 linkage groups. Each CSSL contained only 1–5 substituted segments and the length of substituted segments ranged from 0.05 to 36.88 c M with an average of 7.75 c M. The total length of the overlapped substituted segments was 2922.57 c M, which was 2.61 times of the whole tobacco genome length. And the CSSLs covered length was 1114.32 c M, with a covered ratio of 99.45% in the recurrent tobacco genome. The CSSLs constructed in this study are excellent genetic materials for gene mapping, QTL analysis of complicated traits, and developing varieties by marker assisted selection in Nicotiana tabacum L.