Physical mapping and molecular-cytogenetic analysis of substitutions and translocations involving chromosome 1D in synthetic hexaploid triticale

Chromosome 1D, which carries the advantageous alleles of glutenin and gliad in, attracts major interest with respect to improving the bread-making qual ity of triticale. Eighty-one BC1F4 lines from different primary and seconda ry hexaploid triticale crosses were selected for 1D chromatin analysis usin g SDS-PAGE and C-banding. In situ hybridization and RFLP-based comparative physical mapping of group 1 chromosomes revealed 20 lines with complete 1D (1A) substitutions. Nine 1D (1B) substitutions, six 1D (1R) substitutions a nd one 1D addition line were also selected. Three lines were pure AABBRR he xaploids without any D-genome chromosomes. For the remaining 42 lines (51.8 %), a wide spectrum of 20 different recombinations between chromosomes 1A a nd 1D was uncovered. Altogether, they were generated without any earlier ir radiation, tissue culture or genetic induction of chromosome pairing. In ad dition, 14 translocations between 1B/1D, 1A/1R, 1B/1R, 1D/1R and 1A/1B were detected. Considerable variability for sedimentation values was found, wit h the highest sedimentation values among lines with complete 1D chromosomes . The implications of using triticale as a model for generating compensatin g chromosome rearrangements in defined homoeologous groups and the breeding potential of D-genome chromatin introgressed into triticale with improved sedimentation values are discussed.