C-BANDING POLYMORPHISM AND LINKAGE OF NONHOMOLOGOUS RFLP LOCI IN THE D-GENOME PROGENITOR OF WHEAT

Chromosomes from four different accessions of Triticum tauschii, used as parents in generating F2 populations for RFLP genetic linkage map c onstruction, were analyzed by C-banding. The accessions consist of the varietal taxa strangulata (AUS 21929) and meyeri (AUS 18911), and two genotypes of var. typica (AUS 18902 and CPI 110730 from Iran and Afgh anistan, respectively). Chromosomes 1D and 7D of T tauschii var. typic a AUS 18902 are involved in a reciprocal interchange forming transloca ted chromosomes, TIDS.7DL and T7DS.1DL, with the break-points being lo cated within the centrometric region. The formation of quadrivalent co nfiguration in F1 hybrids provided further confirmation of the recipro cal translocation. Genetic linkage mapping of additional RFLP markers located on homoeologous group 1 and 7 chromosomes showed consistent li nkage to a composite group of proximal markers on chromosomes 1D and 7 D of a previously published map derived from the F2 progeny of AUS 189 02 x AUS 18911. A high frequency of RFLP genotypes transmitted by the translocation parent was prevalent in the proximal regions of chromoso mes 1D and 7D. Genotypic frequencies expected of the nontranslocated p arental RFLP markers was evident only in the distal regions of these c hromosomes.