披碱草和野大麦杂种F1与BC1代细胞遗传学研究

对亲本披碱草(Elymus dahuricus)和野大麦(Hordeum brevisubulatum)及其杂种F1和BC1代体细胞染色体数和花粉母细胞(PMC)减数分裂染色体行为进行观察和分析.结果表明:亲本披碱草的染色体数为2n=42,野大麦为2n=28;正、反交杂种F1染色体数均为35;BC1代染色体发生了数目上的差异,变异范围为28～35,并出现很多非整倍性植株;披碱草的PMCMI二价体配对频率很高,野大麦PMCMI出版少量的四价体、三价体和单价体,但以二价体占优势;正反交杂种F1减数分裂不规则,单价体的普遍存在是造成杂交不育的重要原因;BC1代的PMCMI单价体频率较F1代有所下降,二价体频率有所增高,有些株系的环状二价体占绝对优势,这为杂种育性恢复提供了细胞学依据.

Studies on Cytogenetics of Elymus Dahuricus, Hordeum Brevisubulatum and Their Hybrid F1 and BC1

The chromosome number in the root tip cell and chromosome behavior at meiosis in pollen mother cell were observed and analyzed. The results showed that chromosome numbers of parents E. dahuricus and H. brevisubulatum were 42 and 28 respectively. The chromosome numbers of both E. dahurcus X H. brevisubulatum F1 and H. brevisubulaturn X E. dahuricus Flwere 35. The chromosome numbers of BC~varied, ranging from 28- 35, and many no-ploidy plants appeared. The bivalent pairing frequency of E. dahuricus was very high. A few tetravalents, trivalents and univalents appeared in pollen mother cells of H. brevisubulatum at metaphase I, but bivalents were dominant. The meiosis of hybrid F1 was not regular and the general existence of univalents was the main cause of sterility of hybrid F1 The univalent pairing frequency in pollen mother cell of BC1 at metaphase I decreased in some extent, while the bivalent pairing frequency increased, with the bivalents in some lines becoming dominant. All this provided cytological basis for the sterility restoration of the hybrid.