Karyotype Analysis inTriticum: II — Analysis ofT. AraraticumJakubz. andT. TimopheeviZhuk. and Their Relationships with Other Tetraploid Wheats

Abstract

SUMMARYAnalysis of karyotypes of T. timopheevi and T. araraticum (respectively a cultivated and a wild tetraploid wheat belonging to the same species) demonstrated an identical chromosome morphology. Both are quite different from the karyotypes presented by other tetraploid wheats belonging to T. turgidum group. Differences in total chromosome length and arm ratio are evident, particularly in satellited chromosomes. Moreover, chromosomes with subterminal and median centromere are more frequent in timopheevi than in turgidum lines. Differences in chromosome morphology support the hypothesis of a distinct origin of the two groups of tetraploid wheats or, at least, give the evidence of occurrence, during differentiation, of large chromosome restructurations. Current hypotheses of origin and speciation of tetraploid wheats are discussed in the light of phytogeographical, genetical, cytogenetical, cytological and biochemical data available.