Detection of wheat-alien recombinant chromosomes using co-dominant DNA markers

A study of homoeologous recombination along almost the complete genetic len gth of two homoeologous chromosomes in the Triticeae was conducted. Sears' ph1b mutant was used to induce homoeologous pairing between chromosomes 7A of common wheat and 7Ai-1 of Agropyron intermedium. 390 ph1b ph1b homozygou s F-3 progeny were screened using six co-dominant DNA markers (RFLP loci). 63 of the progeny (16%) were putative recombinants, showing dissociation of RFLP markers within the arm(s). Progeny tests of self-fertile putative rec ombinants confirmed the dissociation phenotypes observed in the F-3 progeny . No recombination could be confirmed in 117 F-3 progeny plants having the Ph1-allele (control population). Frequencies and distribution of chiasmata along the chromosome arm 7AS were analysed using additional RFLP markers. T he patterns of recombination between the two homoeologous chromosomes were found similar to those reported for homologous recombination between the sa me markers on short arms of group 7 chromosomes of Triticeae.