Cell selection as a possible reason for the specificity of somaclonal variation in pea

A study of regenerants obtained from long-term callus cultures of different pea (Pisum sativum L.) genotypes revealed specificity of in vitro mutagenesis. The specificity was displayed in the preferential generation of the somaclonal variations affecting quantitative and developmental characters. About 60% of regenerated lines obtained from the cultivar Ranny Zeleny carried mutations in the Lf and Sn loci, which control initiation of flowering. An in vitro study of isogenic lines differing at the Lf and Sn loci illustrates the growth advantages of mutant genotypes in tissue culture. These experiments suggest that mutations affecting developmental characters (e.g. mutations in loci which control flowering behaviour) may be expressed in tissue culture and may cause increased adaptation in mutant cells to the in vitro conditions. Rapid propagation of mutant cells during in vitro culture may lead to a higher proportion of quantitative mutations among the regenerated plants.