结球甘蓝染色体片段替换系构建

Construction of Cabbage Chromosome Segment Substitution Lines

以结球甘蓝(Brassica oleracea L.var.capitata)育种骨干亲本R2-P2(圆球形,抽薹晚,硫苷含量低,高感黑腐病、枯萎病和霜霉病)为轮回亲本,以野生甘蓝自交系R4-P1(不结球,抽薹早,蜡质厚,硫苷含量高,对黑腐病、枯萎病和霜霉病等多种病害具有抗性)为供体亲本,通过连续回交、自交和分子标记辅助选择,构建出一套由163个具有R2-P2遗传背景且具有R4-P1供体染色体片段单株组成的染色体片段替换系(Chromosome segment substitution line)。该替换系群体具有102个染色体替换片段,均匀分布在1~9号染色体上,平均每个株系携带1.3个染色体片段,平均替换长度为5.62 Mb。替换片段总长度为573.74 Mb,覆盖亲本R4-P1全基因组的73.4%,其中单片段替换片段总长度为139.91 Mb,覆盖全基因组的26.5%,双片段替换片段总长231.41 Mb,覆盖亲本R4-P1全基因组的43.82%,含有3个替换片段总长度为201.3 Mb,覆盖供体亲本基因组25.98%。

In this experiment,cabbage R2-P2,a foundation parent with head,late bolting and low glucosinolate content,high susceptibility to black rot,Fusarium wilt and downy mildew was served as the recurrent parent.On the contrary,the donor parent R4P1 is a wild cabbage inbred line R4-P1 with no-heading,early bolting,thick wax,high glucosinolate content,and resistance to black rot,Fusarium wilt,downy mildew and other diseases.Resultly,the Chromosome segment substitution lines(CSSLs)was both possessed the genetic background of R2-P2 and individual donor fragment of R4-P1.The CSSLs with 163 lines was constructed by continuous backcross,selfing and marker-assisted selection.The CSSLs contained 102 substituted segments totally,which were derived from genome of donor parent R4-P1 and evenly distributed on nine chromosomes.There were average 1.3 chromosome fragments on a line at least.The whole length of the substituted segments was 573.74 Mb with an average length of 5.62 Mb,which covered the 73.4%of complete DNA sample of R4-P1.Among them,139.91 Mb of single substituted segments covered the 26.5%of complete DNA.Besides,the double-segment replacement fragments were 231.41 Mb,which was accounted for 43.82%.Meanwhile,the total length of three replacement fragments was 201.3 Mb,covering 25.98%of the donor parent genome.