High frequencies of homoeologous and even non-homologous chromosome recombination in Brassica hybrids can transfer useful traits between genomes, but also destabilise synthetic allopolyploids. We produced triploid hybrids (2n = 3x = ABC) from the cross B. napus (rapeseed, 2n = 4x = AACC) × B. nigra (black mustard, 2n = 2x = BB) by embryo rescue and allohexaploid hybrids (2n = 6x = AABBCC = 54) by chromosome doubling of the triploids. These hybrids demonstrated resistance to blackleg disease (causal agent: Leptosphaeria maculans) inherited from their B. nigra parent. In order to assess the possibility of transfer of this resistance between the B genome and the A and C subgenomes of B. napus, as well as to assess the genomic stability of allohexaploids from the cross B. napus × B. nigra, frequencies of non-homologous chromosome pairing in these hybrids were assessed using classical cytogenetics and genomic in-situ hybridization. Meiosis was highly irregular, and non-homologous chromosome pairing between the B genome and the A/C genomes was common in both triploid hybrids (observed in 38% of pollen mother cells) and allohexaploid hybrids (observed in 15% of pollen mother cells). Our results suggest that introgression of blackleg resistance from the B genome into the A or C genomes should be possible, but that allohexaploids from this genome combination are likely unstable.

中文翻译：

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甘蓝型油菜和黑芥子之间的杂种表现出B和A / C基因组之间的频繁配对以及对黑腿病的抗性。

芸苔属杂种中高频率的同源甚至非同源染色体重组可以在基因组之间转移有用的性状，但也会破坏合成的异源多倍体。我们通过胚胎挽救和异源六倍体杂种（2n = 6x）从杂交油菜（油菜，2n = 4x = AACC）×黑芥（黑芥菜，2n = 2x = BB）生产三倍体杂种（2n = 3x = ABC） = AABBCC = 54）的三倍体染色体倍增。这些杂种表现出了对黑粉病父母的黑腿病（病原体：Leptosphaeria maculans）的抗性。为了评估这种抗性在B.napus的B基因组与A和C亚基因组之间转移的可能性，以及评估杂交B. napus×B. nigra的异六倍体的基因组稳定性，使用经典细胞遗传学和基因组原位杂交技术评估了这些杂种中非同源染色体配对的频率。减数分裂是高度不规则的，并且在三倍体杂种（在38％的花粉母细胞中观察到）和异六倍体杂种（在15％的花粉母细胞中观察到）B基因组和A / C基因组之间的非同源染色体配对很常见。 。我们的结果表明，应该有可能将黑脚病抗性从B基因组渗入A或C基因组，但这种基因组组合的异六倍体可能不稳定。B基因组和A / C基因组之间的非同源染色体配对在三倍体杂种（在38％的花粉母细胞中观察到）和异六倍体杂种（在15％的花粉母细胞中观察到）很常见。我们的结果表明，应该有可能将黑脚病抗性从B基因组渗入A或C基因组，但这种基因组组合的异六倍体可能不稳定。B基因组和A / C基因组之间的非同源染色体配对在三倍体杂种（在38％的花粉母细胞中观察到）和异六倍体杂种（在15％的花粉母细胞中观察到）很常见。我们的结果表明，应该有可能将黑脚病抗性从B基因组渗入A或C基因组，但这种基因组组合的异六倍体可能不稳定。