甘蓝型油菜与埃塞俄比亚芥杂交创制有限花序新种质

Innovation of New Determinate In?orescence Germplasm via Hybridization between Brassica napus and Brassica carinata

远缘杂交是作物遗传改良和种质创新的重要途径。本研究通过甘蓝型油菜(2n=38,AACC)与埃塞俄比亚芥(2n=34,BBCC)的种间杂交获得了形态属于两亲本中间型的杂种F1,且表现埃塞俄比亚芥的有限花序特性。该杂种具有预期的体细胞染色体数目(2n=36,ABCC),GISH分析显示含有8条B染色体组的染色体;在减数分裂终变期的花粉母细胞中出现多种染色体配对构型,在后期Ⅰ染色体分离多以17∶19分离为主,但在后期Ⅰ及后Ⅱ期均出现大量的落后染色体、染色体桥,导致花粉败育。将该杂种与亲本甘蓝型油菜品种中双11连续回交,获得有限花序的后代材料BC5F1,其他形态特征与中双11类似,其体细胞染色体数目恢复至2n=38,减数分裂染色体行为也正常;GISH分析虽检测到少数B染色体组信号,但没有整条的染色体。利用46对B基因组特异引物对有限花序杂种及后代材料进行SSR扩增,发现在杂种F1及部分BC5F1植株中都能检测到B基因组特异带,表明有埃塞俄比亚芥B基因组遗传成分的导入。所创建的有限花序新品系为油菜的遗传改良和选育适于机械化作业的新品种提供新材料。

Distant hybridization is an important approach in crop genetic breeding and germplasm creation.In this study,the F1 hybrids were produced by interspecific hybridization between Brassica napus L.(2n=38,AACC)and B.carinata A.Braun(2n=34,BBCC),and they showed determinate inflorescence characteristic from B.carinata A.Braun and the intermediate morphology of both parents.F1 hybrids showed the expected chromosomal composition(2n=36,ABCC)and eight B.carinata A.Braun(referred B)chromosomes from by GISH analysis.Their pollen mother cell(PMCs)showed multiple chromosome pairing configuration at diakinesis of meiosis,with main segregation rate of 17∶19 at anaphaseⅠ(AⅠ).A number of lagging chromosomes and chromosomal bridges appeared during AⅠand AⅡ,which caused pollen abortion.By continuous backcross using its parental line Zhongshuang 11(B.napus L.),the BC5F1 lines with determinate inflorescence were obtained and they had similar morphology with Zhongshuang 11.Their somatic chromosomes(2n=38)showed normal programmed meiosis,and only minor B chromosome signals but whole chromosomes were detected by GISH analysis.By marker assisted detection using 46 pairs of B genome specific SSR primers,B genome specific bands are detectable in F1 hybrid and a few of BC5F1.This result indicated that the chromosomal segments of B.carinata A.Braun were successfully introduced into B.napus L.Thus,a number lines with new determinate inflorescence will become useful in rapeseed breeding for new varieties suitable for mechanized operation.