Somaclonal variation from cultured immature embryos of sister lines of rye differing in heterochromatic content

Somaclonal variation occurred among rye plants regenerated from cultured immature embryos of five sister lines that differed in their content of telomeric heterochromatin. Variation was observed in morphology, chromosome number, and secalin seed storage proteins. Morphological variation was present in 9.7% of the regenerants and included albinism and variegation, which appeared in different frequencies among the lines. Chromosome variation occurred in 15.8% of the regenerants and included translocations, tetraploidy, and trisomy in addition to meiotic disturbances such as centromere misbehaviour and asyndesis. Some of the regenerated plants were mosaic for the structural and numerical chromosome aberrations. The nature of the chromosome variation also differed among the lines. A single variant in the 40K γ-secalins was detected. The occurrence of variation is discussed in relation to differences in morphogenetic response of the rye lines and to the genotypic component of instability in culture.Key words: somaclonal variation, immature embryo culture, rye heterochromatin, chromosome variation, secalins.