Variability in potato tissue culture

Abstract

Tissue culture systems in potato (Solanum tuberosum L.) that involve a callus phase, such as regeneration of plants from protoplasts or expiants, can be accompanied by phenotypic variability, or somaclonal variation. The extent of this variability appears to be greatest in protoplast-derived potato plants. Cytological studies have shown that some of the variation observed in regenerated potato plants arises from numerical and structural chromosome variation. Aneuploidy is particularly a problem in regeneration from protoplasts. Factors affecting the degree of chromosome instability include the genotype and ploidy of the starting material, the regeneration system adopted, the source of the plant cells and the composition of the tissue culture media. Studies at the molecular level have indicated that changes in the potato genome, other than those associated with chromosomes, also occur. The implications of somaclonal variation in potato, particularly with regard to its potential usefulness for plant breeding are discussed.