PAIRING AND TRANSMISSION OF CHROMOSOMES OF THE HYBRIDS BETWEEN AMPHIDIPLOID OF TRITICUM DURUM DESF.-DASYPYRUM VILLOSUM(L.)CANDARGY AND TRITICUM AESTIVUM(L.)

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。

PAIRING AND TRANSMISSION OF CHROMOSOMES OF THEHYBRIDS BETWEEN AMPHIDIPLOID OF TRITICUM DURUMDESF.-DASYPYRUM VILLOSUM(L.) CANDARGYAND TRITICUM AESTIVUM (L.)

Studying on chromosome pairing at metaphas Ⅰ in the F1 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 F1 gametes is evidently not at random. The chromosome numbers in F2 and BC1F1 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 F1 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.