甘蓝型油菜千粒重性状的QTL初步定位研究

千粒重是油菜重要的产量相关性状之一,构建油菜遗传连锁图谱是研究其产量性状基因的前提。本研究利用小孢子培养技术,选育出了甘蓝型油菜大粒品系(G-42)和小粒品系(7-9)的纯合DH系DH-G-42和DH-7-9,其千粒重分别为6.24 g和2.42 g,二者比值达2.58。以DH-G-42为母本、DH-7-9为父本,构建了含190个单株的F2遗传作图群体,利用SSR和SRAP标记技术绘制遗传连锁图谱,该图谱共包含20个连锁群,涉及128个SSR标记和100个SRAP标记,图谱总长1546.6cM,标记间平均图距为6.78cM。本研究共检测到3个与千粒重性状相关的QTL,分别位于A9和C1连锁群,其中qSW-A9-1和qSW-A9-2贡献率分别达到10.98%和27.45%,均可视为控制粒重的主效QTL。本研究为后续进行油菜千粒重性状QTL的精细定位分析、分子标记辅助选择育种及新基因的克隆等奠定了基础。

Preliminary QTL Mapping for 1000-seed Weight Trait in Brassica napus

Thousand-seed weight of Brassica napus is one of most important yield traits. Construction of the genetic linkage map will provide the basis for research on the genetic base of quantitative trait in Brassica napus. By microspore culture technology, we screened the pure lines DH-G-42 with large seed and DH-7-9 with small seed, their thousand-seed weights were 6.24 g and 2.42 g, respectively, and the ratio of 1000-seed weight for two lines is 2.58. A genetic linkage map with F2 population including 190 individuals derived from a cross of DH-G-42  DH-7-9 were established by SSR and SRAP markers. The map consisted of twenty linkage groups anchored 128 SSR and 100 SRAP markers and covered 1546.6 cM with an average marker interval of 6.78 cM. QTLs located in A9 and C1 linkage group were identified to be significant for the 1000-seed weight trait. The qSW-A9-1 and qSW-A9-2 explained 10.98% and 27.45% of the phenotypic variation, which could be considered as main effect QTL for the 1000-seed weight trait. Our study will be beneficial to the fine QTL mapping, the marker-assisted breeding and the novel genes cloning in Brassica napus.