Abstract
Tetraploid wheats were divided into the Emmer (genomic constitution, AABB) and the Timopheevi (AAGG) groups based on the low level of meiotic chromosome pairing and sterility in their hybrids. Triticum dicocoides lines KU8821A and KU8821C and T. araraticum line KU8821B, which show a high level of meiotic chromosome pairing in the hybrids, have been considered to be intermediate types between the Emmer and the Timopheevi wheats. These intermediate types may play an important role in the differentiation of tetraploid wheats. Chromosome structural differentiation was examined by the N-banding technique. These lines showed either the banding patterns of the Timopheevi or of the Emmer groups, and were not intermediate plants between the two groups based on the chromosome structure. The present results suggest that the Emmer and the Timopheevi groups were derived diphyletically in the evolution of tetraploid wheats.
