College of Horticulture and Landscape, Southwest University, Chongqing, China.
College of Agronomy and Biotechnology, Southwest University, Chongqing, China.
PLoS One. 2018 Mar 1;13(3):e0193548. doi: 10.1371/journal.pone.0193548. eCollection 2018.
The strategies of crossing B. napus with parental species play important role in broadening and improving the genetic basis of B. napus by the introgression of genetic resources from parental species. With these strategies, it is easy to select new types of B. napus, but difficult to select new types of B. rapa or B. oleracea by self-pollination. This characteristic may be a consequence of high competition with B. napus gametes. To verify the role of gamete viability in producing new B. napus individuals, the meiotic chromosome behavior of the interspecific hybrid between B. napus (Zhongshuang 9) and B. oleracea (6m08) was studied, and microspore-derived (MD) individuals were analyzed. The highest fitness of the 9:19 (1.10%) pattern was observed with a 5.49-fold higher than theoretical expectation among the six chromosome segregation patterns in the hybrid. A total of 43 MD lines with more than 14 chromosomes were developed from the hybrid, and 8 (18.6%) of them were B. napus-like (n = 19) type gametes, having the potential to broaden the genetic basis of natural B. napus (GD = 0.43 ± 0.04). It is easy to produce B. napus-like gametes with 19 chromosomes, and these gametes showed high fitness and competition in the microspore-derived lines, suggesting it might be easy to select new types of B. napus from the interspecific hybrid between B. napus and B. oleracea.
通过将亲本物种的遗传资源导入油菜，油菜与亲本物种的杂交策略在拓宽和改善油菜遗传基础方面发挥了重要作用。利用这些策略，很容易选择新型油菜，但通过自交很难选择新型白菜或甘蓝。这一特性可能是与油菜配子高度竞争的结果。为了验证配子活力在产生新型油菜个体中的作用，研究了油菜（中双 9 号）和白菜（6m08）种间杂种的减数分裂染色体行为，并对小孢子衍生（MD）个体进行了分析。在杂种中，观察到最高的 9:19（1.10%）模式的适应性为理论预期的 5.49 倍，六种染色体分离模式中的适应性最高。从杂种中总共开发了 43 条具有 14 条以上染色体的 MD 系，其中 8 条（18.6%）为油菜样（n = 19）类型配子，具有拓宽天然油菜遗传基础的潜力（GD = 0.43 ± 0.04）。很容易产生具有 19 条染色体的油菜样配子，这些配子在小孢子衍生系中表现出高适应性和竞争力，表明从油菜与白菜的种间杂种中很容易选择新型油菜。
