中国春双端二体中端体的配对研究

Studies of Telocentric Chromosome pairing in Triticum aestivum L. cv Chinese Spring Double Ditelosomics

21个中国春双端二体与中国春品种杂交,观察了杂种F_1减数分裂中期Ⅰ端体与相应染色体的配对。结果表明:14个组合的中期Ⅰ具有1个异形三价体的PMC的百分数超过90%;有3个组合(6A、5B和6D)分别为89.87%、83.56%和85.71%;2个组合(4A和1B)低于80%。在4A、1B和5B的3个组合中,具有1个异形二价体和1个单价端体的PMC超过15%。在4A、1B和4D的组合中,还有一定频率的PMC具有2个单价端体。用21个组合中端体配对频率计算的二价体频率与中国春品种中期Ⅰ构型频率基本一致。这些结果表明,染色体臂作为端体时和它作为双臂染色体的一部分时,是以同样的方便程度配对的。

Meiotic analyses of PMCs at MI were conducted on the hybrids of Triticum aestivum L. cv Chinese Spring double ditelosomics and Chinese Spring. The results revealed that in most of the hybrids, the frequences of PMC with (ttl''') ranged from 70.45% -100%, those with (t',t') varied between 0% -12.5%, and those with (tl',t') were all lower than 15% except in the hybrids involving 4A, IB, and 5B, in which the PMCs with (tl'',t') accounted for 27.27%, 15.63% and 16.44%. respectively. The calculated frequences of bivalent on the telocentric pairing in the hybrids coincide basically with that of the chromosome pairing at MI of PMCs in Chinese Spring. On the basis of resulls obtained, it could be concluded that the telocentric chromosomes paired readily as the complete chromosomes.