Genome flux in tomato cell clones cultured in vitro in different physiological equilibria. II: a RAPD analysis of variability.

An analysis of the effect of changing physiological conditions on genome evolution in tomato cell populations has been carried out on long-term in vitro cultured clones grown on different auxin–cytokinin equilibria or selected for low–high competence for active defense against Fusarium oxysporum f.sp. lycopersici. RAPD analysis, confirmed through pattern rehybridization, was used as a random tool to measure the genetic variability. Through the use of a modified ANOVA, variation was shown to depend on both the initial genotype and the physiological conditions. Pattern correlation analysis through a mutual information algorithm suggested the fixation of RAPD patterns specific to physiological equilibria. The results are discussed in view of the possible relevance for evolution at hierarchical levels higher than cell populations. Key words : tomato clones, somaclonal variation, RAPD, coadaptation.