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采取胚胎挽救技术,培养103个子房获得4个Brassica juncea×Brassica barrelieri F_1杂种植株。杂种形态介于两亲本之间,花期长,分枝多,花粉高度不育,减数分裂表现异常。F_1花粉母细胞的减数分裂中期(MI),来自两亲本物种的染色体按染色体组彼此分开,集中分布成10/18状,呈现罕见的染色体组界沟。10与18条染色体之间最多见3个二价体联会。并观察到染色体组内的次级联会现象。根据染色体组间和组内联会的特点,作者认为两个亲本物种的染色体组构型可以表示为aabbccdefg(B.barrelieri)和bcdhhhiiijjkklmnop(B.juncea)。研究表明,(1)两个亲本物种在形态和染色体的同源性等方面具有较大差异,B.barrelieri的分类地位值得进一步商榷。(2)两个亲本存在一定的遗传同源性并具有遗传物质交流的可能性。(3)第一次减数分裂中期染色体组隔沟的出现以及染色体有规律的分布显示两个物种间的基因重组主要发生在部分同源的染色体之间,无同源性的染色体之间的重组将十分困难。
Take embryo rescue technology, cultivate 103 ovary to obtain 4 Brassica juncea × Brassica barrelieri F_1 hybrid plants. Hybrid between the two parents in between, long flowering, more branches, pollen highly sterile, abnormal performance of meiosis. The metaphase (MI) of F_1 pollen mother cells, the chromosomes from the amphipathic species separated from each other by chromosomal group, concentratedly distributed in 10/18 shape, showing a rare ditch of the genome. The most common 3 bivalent associations between 10 and 18 chromosomes. And observed secondary associations within the genome. Based on the characteristics of the chromosomal and intramuscular associations, the authors consider that the chromosomal configuration of the two parental species can be expressed as aabbccdefg (B. barrelieri) and bcdhhhiiijjkklmnop (B. juncea). Studies have shown that (1) the two parental species have great differences in their morphological and chromosomal homologies, and the classification status of B. barrelieri is worthy of further discussion. (2) The two parents have certain genetic homology and the possibility of genetic material exchange. (3) The appearance of the first meiotic metaphase genomic ditches and the regular distribution of chromosomes showed that the recombination between the two species mainly occurred between partially homologous chromosomes and no homologous chromosomes Reorganization will be very difficult.