Morphological and Cytogenetic Analysis on the Advanced Generations of Generic Hybrids between Brassica napus and Orychophragmus violaceu

[Objective] This study aimed to reveal the genetic changes of advanced generation hybrids between Brassica napus and Orychophragmus violaceus. [Method] The morphological characteristics such as the plant shape, branching sites, leaf shape, leaf color, primary branches and secondary branches, as well as the cytological characteristics of the advanced generation hybrids (F8-F10) between B. napus and O. violaceus were observed. [Result] The morphology analysis revealed that the hybrid progeny was more like B. rapa in leaf shape, leaf color, plant shape and early flowering phenotype, whereas more like B. napus in number of secondary branches, silique length and 1 000-seed weight. Analysis on the cytogenetics characteristics showed that these advanced inbred progenies were hypoploids with less than 38 chromosomes; moreover, all the chromosomes from O. violaceus had been lost. Chromosome pairings at meiotic diakinesis of hybrids between the advanced inbred progenies and B. rapa revealed that chromosomes lost in hypoploids possibly belonged to the C genome of B. oleracea. With generations developing, chromosomes number of plants from two populations gradually increased and developed into the number of B. napus (2n=38). [Conclusion] This study will provide reference to reveal the source of chromosome lost in hypoploids and the morphological change of hybrids.

甘蓝型油菜与诸葛菜属间杂种后代亚倍体类型及细胞遗传学研究

在甘蓝型油菜与诸葛菜属间五倍体杂种后代中 ,鉴定出多种亚倍体类型。在P3 群体中 ,细胞学观察发现诸葛菜染色体替代甘蓝型油菜的 1对染色体异代换植株 ,体细胞由 36～ 38条染色体的 3种类型组成 ,但具 38条的体细胞与花粉母细胞 (PMC)占绝对优势 ,育性正常。在P4群体后代中鉴定出 3株具有 37条染色体的单体类型 ,形态与结实率均不相同。其中 1株生长势很强 ,其体细胞与PMC均由多种类型构成 ,但具 37条的体细胞与花粉母细胞占主要比例 ,未配对的染色体形态较小 ,对生长无明显影响。在染色体数为 4 4与 4 1的两种超倍体 (P3 群体 )后代 ,鉴定出具有 2 9～ 32条染色体的 4种亚倍体 ,除染色体数为 2 9的植株外 ,其余均为混倍体 ,它们的减数分裂异常 ,花粉育性低。

甘蓝型油菜和诸葛菜属间杂种高世代材料形态学和细胞学分析

[目的]进一步揭示甘蓝型油菜和诸葛菜属间远缘杂种高世代(F8～F10)材料的遗传变异规律。[方法]以甘蓝型油菜和诸葛菜属间杂种高世代群体为材料,对甘蓝型油菜和诸葛菜远缘杂交后代表型偏白菜型油菜变异群体进行形态、细胞学方面的研究。[结果]形态学分析表明,杂种后代叶型、叶色、株型、早花性状偏向白菜型油菜,而二级分枝数、角果长度和千粒重与甘蓝型油菜Oro更为接近;细胞学研究表明,这些杂种高世代材料细胞中已不含诸葛菜染色体,多数植株都为少于38条染色体的亚倍体;与白菜型油菜杂种的减数分裂配对结果显示,这些亚倍体后代细胞中丢失的可能是来自C基因组的染色体,随着世代的增加,体细胞染色体数目都有向甘蓝型油菜2n=38升高和回归的趋势。[结论]该研究为揭示杂种后代亚倍体中丢失染色体的来源及形态学改变的原因奠定基础。

甘蓝型油菜亚倍体(2n=30)后代的染色体及基因组组成分析

甘蓝型油菜亚倍体（2n=30）与白菜杂交后代的染色体数目为2n=22、24—28、31，自交后代的染色体数目为2n=30—36。对此亚倍体自交后代进行扩增片段长度多态性（AFLP）指纹分析并按照类平均法（UPGMA）进行聚类分析，它们被明显分为甘蓝型油菜类（I）和白菜及白菜型油菜类（Ⅱ）两类。I类植株基因组组成与甘蓝型油菜相似，Ⅱ类植株则与白菜及白菜型油菜相似。在花粉的可染性、单角结实率和单株结角率等性状上，Ⅱ类植株较I类植株表现更好。据此推测白菜型后代是由A基因组染色体和与A基因组同源性较高的部分C基因组染色体的配子结合而产生。