Studying on chromosome pairing at metaphas Ⅰ in the F1 hybrids between the 6x primary amphidiploid of Triticum durum-Dasypyrum villosum and ph1b Chinese Spring and four bread wheat landraces from Sichuan shows marked differences in chromosome pairing depending on the wheat genotypes used, which suggested there is a ph or ph-like gene(s) in the population of landraces in Sichuan. Homologous pairing within the A and the B chromosomes are disturbed by the monosomic chromosomes of V and D genomes to some extent. Transmission of the chromosomes in the F1 gametes is evidently not at random. The chromosome numbers in F2 and BC1F1 plants of these AABBDV hybrids range between 29 and 65. It is possible that some gametes originating from dyads, triads, pentads, and hexads, besides normal tetrads at the telophase Ⅱ involved in the process of fertilization in F1 hybrids. The results suggest that the progenies of the AABBDV hybrids could be developed form not only the higher-polyploidy (8x), but also the lower-polyploidy (4x and 6x), and genotypes with mixed V and D genomic constitution are likely to develop.%对初级六倍性硬粒小麦-簇毛麦双二倍体与来源于四川的三个地方品种(系)和一个栽培普通小麦品种(包括ph1b中国春小麦)所形成的杂种F1在减数分裂中期Ⅰ的配对行为进行了研究.结果表明,小麦亲本不同,杂种F1之间的染色体配对存在明显的差异.四川的地方品种群体中可能存在ph或类似干ph的基因,促进染色体的配对.另外,在杂种F1(AABBDV)中,单倍性染色体组D和V的存在部分地扰乱了A和B染色体组的同源配对.末期Ⅱ中,除了正常的四分体外,还存在二分体、三分体、五分体及六分体.对杂种F2和BC1F1的染色体计数研究表明,其染色体数目的变化范围为2n=29至2n=65,有的植株的染色体数目超过了预期的染色体数目,说明染色体通过杂种F1的传递偏离了随机模式.部分二、三、五或六分体所形成的配子参与了受精结实.因而在硬粒小麦-簇毛麦双二倍体与普通小麦的杂种后代中,不仅可望获得混合有D、V染色体结构的2n=42的植株,而且还可能获得其它高倍性(8x)和低倍性(4x)的植株,从而为物种的进化指出了一种可能的途径.
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