Origin of aneuploid plants obtained by anther culture in triticale

A very large proportion of plants regenerated from anther culture of triticale F1 hybrids do not show the euploid number of chromosomes. Of 408 androgenetic plants checked for their chromosome numbers, 228 were aneuploid, of which 39 had one or several telosomes. Two observations suggest that most of the chromosome variations observed probably preexist in microspores of the F1 hybrids and would be caused by meiotic irregularities: on the one hand, the majority of these phenomena involve R-genome chromosomes, which also give rise to meiotic univalents; on the other hand, the chromosome number frequency distribution of the microspores from a fairly asyndetic hybrid fits well with that of the androgenetic plants. Thus aneuploidy and chromosome rearrangement do not implicate the in vitro technique itself but rather the choice of the material in triticale.Key words: × triticosecale, in vitro culture, chromosome variation, aneuploidy, C-banding.