Fertile allohexaploid Brassica hybrids obtained from crosses between B. oleracea and B. juncea via ovule rescue and colchicine treatment of cuttings
Fertile allohexaploid Brassica hybrids obtained from crosses between B. oleracea and B. juncea via ovule rescue and colchicine treatment of cuttings
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DOI：
10.1007/s11240-019-01728-x
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发表时间：
2019-11
期刊：
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通讯作者：
M. Mwathi;Mehak Gupta;Daniela Quezada-Martinez;A. Pradhan;J. Batley;A. Mason
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文献类型：
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作者：
M. Mwathi;Mehak Gupta;Daniela Quezada-Martinez;A. Pradhan;J. Batley;A. Mason
异源六倍体高粱（2n = AABBCC）在自然界中并不存在，但由于其具有将六种栽培高粱中的有用性状结合起来的潜力而引起人们的兴趣，这些栽培高粱具有A、B和C基因组的组合，并具有额外的等位基因杂种优势。本研究旨在通过B. juncea和一些拟南芥C基因组物种。我们利用胚珠拯救克服杂交障碍，并采用不同的秋水仙素处理方法诱导ABC杂种染色体加倍为AABBCC异源六倍体，从而恢复育性。只有十字架。oleracea×B. junca是成功的，从一个基因型组合产生了6个三倍体杂种。含秋水仙素的再生培养基不能使这些杂种的染色体数目加倍，但用0.05 - 0.25%的秋水仙素处理插穗成功地产生了~ 200粒S1异源六倍体种子。S_1代植株减数分裂中期Ⅰ产生7-84%的花粉，结实0-390粒，二价体23-27个，单价体0-3个。我们的研究结果突出了与野生C基因组物种一起工作的困难，但表明我们的方法对于在该杂交组合中产生整倍体、染色体加倍的后代具有实用性。此外，甘蓝×B.异源六倍体杂种可能包含有用的遗传因子，以改善异源六倍体种质库中的减数分裂稳定性和育性。
An allohexaploidBrassicacrop (2n = AABBCC) does not exist naturally, but is of interest for its potential to combine useful traits found in the six cultivatedBrassicaspecies which share combinations of the A, B and C genomes with additional allelic heterosis. In this study, we aimed to produce 2n = AABBCC hybrids by crosses betweenB. junceaand a number ofBrassicaC genome species. We used ovule rescue to overcome hybridization barriers and different colchicine treatment methods to induce chromosome doubling of ABC hybrids to AABBCC allohexaploids, thus restoring fertility. Only the crossB. oleracea×B. junceawas successful, with six triploid hybrids produced from one genotype combination. Colchicine-containing regeneration media was unsuccessful in doubling chromosome number in these hybrids, but treatment of cuttings with 0.05 to 0.25% colchicine successfully produced ~ 200 S1allohexaploid seeds. The S1plants produced 7–84% viable pollen and set 0–390 seeds per plant, with 23–27 bivalents and 0–3 univalents during metaphase I of meiosis. Our results highlight the difficulties in working with the wild C genome species, but showed that our methods have utility for producing euploid, chromosome-doubled progeny in this cross combination. Further,Brassica oleracea×B. junceaallohexaploid hybrids may contain useful genetic factors for improved meiotic stability and fertility in allohexaploid germplasm pools.