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剩余杂合系是QTL精细定位的较好衍生群体,它是在重组自交系构建过程中形成的。本研究均匀选择了遍布大白菜全基因组的51对前景/背景标记,随机选择了重组自交系群体构建过程中的57个家系,从中选株系的F_5跟踪检测至F_8。研究数据表明:从F_5至F_8,特定位点的平均剩余杂合率分别是7.06%、3.51%、1.38%和0.38%;剩余杂合位点在所选株系内的基因组覆盖率分别是90.19%、76.47%、52.94%和21.57%,覆盖率迅速降低。值得关注的是:在F_5代时,剩余杂合位点不仅覆盖了90%以上的基因组范围,且特定家系多个杂合位点多位于不同的染色体上,在接下来F_6代的筛选中很容易得到单位点剩余杂合单株。因此,本研究基于前景/背景标记的检测数据认为,高效率筛选剩余杂合单株的时期是F_5~F_6世代。这为提高作物农艺性状精细解析和精准定位提供了参考依据。
The remaining heterozygous line is a better derivative population of QTL fine mapping, which is formed during the construction of recombinant inbred lines. In this study, 51 pairs of foreground / background markers were randomly selected from all genomes of Chinese cabbage. Fifty-seven pedigrees of the recombinant inbred lines were selected randomly from F5 to F8. The data showed that the average residual heterozygosity at the specific loci from F_5 to F_8 was 7.06%, 3.51%, 1.38% and 0.38%, respectively. The coverage of the remaining heterozygous loci in the selected lines was 90.19 %, 76.47%, 52.94% and 21.57%, the coverage rate decreased rapidly. It is noteworthy that at the F5 generation, the remaining heterozygous loci not only cover more than 90% of the genome range, but also more than one heterozygous locus on different chromosomes of a specific pedigree. In the next F6 generation screening It is easy to get the remaining single hybrid plants. Therefore, based on the detection data of foreground / background markers, this study suggests that the screening of the remaining hybrid plants with high efficiency is from F_5 to F_6 generation. This provides a reference for improving crop agronomic traits and precise positioning.