Fluorescence in situ hybridization was applied with total genomic DNA extracted from D.villosum as a probe to characterize chromosome translocations arising from tissue culture in crosses of Triticum aestivum × T. durum D. villosum amphiploids. Chromosome translocations between wheat and D.villosum occurred indeed in callus cells at an average frequency of 1.9 %. Translocations existed not only in callus cells but also in regenerate plants. Three plants with translocation chromosomes were characterized among 66 regenerated plants. One of them was proved to be a reciprocal translocation with break point of wheat chromosome at about one third of a chromosome arm, and that of D. villosum at about one half of a chromosome arm. The break point of the other two translocations was located at, or near centromeres. These similar results from both callus cells and regenerated plants provided evidence that chromosomal translocations could take place in tissue culture. Additional chromosome structure changes (fragments, telocentrics, dicentromeres, and deletions) as well as numerical alterations (including aneuploid and polyploid) were also observed in tissue cultured cells.For 175 regenerated plants arising from immature embryos of crosses between wheat ( Triticum aestivum L.) and 6D/6V substitution stocks, electrophoresis of glutamate oxaloacetate transaminase (GOT) isoenzymes was performed. The GOT V2 enzyme band was absent in two plants (designated as 98R149 and 98R159, respectively). Fluorescence in situ hybridization with total genomic DNA extracted from D.villosum as a probe confirmed the occurrence of translocation between 6V chromosome and an unknown wheat one in the two regenerants mentioned above. 98R149 and 98R159 were immune to powdery mildew ( Erysiphe graminis DC.f.sp. tritici ) inoculation with mix races collected from Hebei Province.These results demonstrated that useful translocations might be produced via tissue culture.
