Genetic improvement of oleic and linolenic acid content through marker-assisted selection in brassica napus seeds | 分子标记辅助选择改良甘蓝型油菜种子油酸和亚麻酸含量

中国人. 摘　　要：本研究以甘蓝型油菜SWHickory×JA177产生的SJDH群体为材料,利用混合分离群体法（Bulked Segregant Analysis,BSA）的原理快速筛选到2个SSR分子标记（BRMS007和BRGMS630）与油酸含量相关,4个SSR分子标记（sN2025,BoGMS798,Na12_D09和OI10_D03）与亚麻酸含量相关。通过构建包含这些标记的局部遗传连锁图,在A5染色体上定位到1个控制油酸含量的主效QTL,可解释油酸表型变异的85.3%;定位到2个位于A4和C4染色体上的亚麻酸含量的主效QTL,可分别解释亚麻酸表型变异的21.5%和59.7%。利用油酸主效QTL两侧的SSR标记BRMS007和BRGMS630在SJDH群体中进行了油酸性状选择效果的鉴定,发现同时使用两侧标记进行选择可将错选率降低到11.7%。然后,从SWHickory×JA177的F2代开始,以JA177为轮回亲本开展回交育种工作。在此过程中,进行油酸的前景分子标记选择、油酸和亚麻酸的表型选择以及分子标记的遗传背景选择。最终在BC2F2和BC3F2代获得了高油酸或低亚麻酸含量且遗传背景基本回复为JA177的改良单株。本研究还探讨不同分子标记类型和不同回交世代对遗传背景选择效果的影响。

英语. Bulked segregant analysis was applied to rapidly identify SSR markers associated with oleic and linolenic acid content in a SJ double haploid （DH） population derived from a cross between two Brassica napus lines SW Hickory and JA177. Two SSR markers, BRMS007 and BRGMS630, and four SSR markers, sN2025, BoGMS798, Na12_D09 and OI10_D03, were identified to be associated with oleic and linolenic acid content, respectively. A major QTL for C18：1, located on the linkage group A5 which explained 85.3% of the oleic acid content variation, and two major QTL for C18：3, located on linkage groups A4 and C4 which respectively explained 21.5% and 59.7% of the linolenic acid content variation, were detected based on the partial linkage maps. The selection efficiency of molecular markers on oleic acid content was further tested in the SJ DH population, and it was found that the rate of false selection could be decreased to 11.7% when selected with BRMS007 and BRGMS630 together. And then BRMS007 and BRGMS630 were used as foreground markers of oleic acid content in the backcross breeding program, in which JA177 was the recurrent parent. The phenotypic selection of oleic and linolenic acid content as well as genetic background selection by molecular markers were also used in the breeding program. And excellent individuals with improved oleic or linolenic acid content and well recovery of genetic background of JA177 were identified in the BC2F2 and BC3F2 generations. The impact of molecular marker types and backcross generations on background selection was also discussed in the present study.