CELL SELECTION AS A POSSIBLE REASON FOR THE SPECIFICITY OF SOMACLONALVARIATION IN PEA

A study of regenerants obtained from long-term callus cultures of diff erent pea (Pisum sativum L.) genotypes revealed specificity of in vitr o mutagenesis. The specificity was displayed in the preferential gener ation of the somaclonal variations affecting quantitative and developm ental characters. About 60% of regenerated lines obtained from the cul tivar Ranny Zeleny carried mutations in the Lf and Sn loci, which cont rol initiation of flowering. An in vitro study of isogenic lines diffe ring 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 cont rol flowering behaviour) may be expressed in tissue culture and may ca use increased adaptation in mutant cells to the in vitro conditions. R apid propagation of mutant cells during in vitro culture may lead to a higher proportion of quantitative mutations among the regenerated pla nts.