Welcome Address.- Welcome Address.- General Problems of Selection of Somaclonal Uariants.- Tissue Culture and Crop Improvement Scientific Dream or New Science ?.- Limitations to the Use of Somaclonal Variation in Crop Improvement.- Chromosome Variation in Plants Regenerated From Protoplasts and Cultured Plant Tissues.- In Vitro Selection for Resistance.- Double-Layer Culture Technique as a Tool for the Selection of Calluses Resistant to Toxic Material from Plant Pathogenic Fungi.- — Non Mendelian Heredity — Genetic Analysis of Variant Plants Regenerated from in vitro Culture : Epigenetics and Epigenic.- Experimental and Theoretical Approach of in vitro Variations.- A Breeder’s Point of View about New Breeding Tools.- Somaclonal Variations in Cereals.- Relative Genetic Stability of Embryogenic Cultures of the Gramineae and Uniformity of Regenerated Plants.- In Vitro Manipulation of Cereal Crops.- Somaclonal Variation in Wheat.- Gametoclonal Variations in Doubled Haploids of Wheat : Biometrical and Molecular Aspects.- Molecular Changes and Possible Origins of Somaclonal Variation.- Somaclonal and Gametoclonal Variation in Wheat, Cotton and Brassica.- Genotype Specific Changes in Amino Acid and Polyamine of Wheat Tissue Culture Induced by Osmotic Stress.- Somaclonal Variation Applied To Wheat Breeding.- In Vitro Regeneration of Plants from Calluses of Triticum Aestivum Cultivars.- Somaclonal Variations in Potato.- Origin and Nature of Somaclonal Variation in Potato.- Variation in the Tissue Culture Progeny of the Chimeral Potato (Solanum Tuberosum L.) Variety Golden Wonder.- Genetic Instability in Vitro of Monohaploid, Dihaploid and Tetraploid Genotypes of Potato.- Selection of Variants by Dual Cultures of Potato and Phytophthora Infestans.- Effects of in Vitro Differentiation on Genetic Stability in Potato.- Characterization of Somaclonal Variations in Potato: A Biochemical Approach.- The Evaluation of Potato Somaclones.- Cryopreservation of Potato Somaclones.- Somaclonal Variations in Ornemental Crops.- Interclonal Variability Induced by in vitro and in vivo Propagation in a Vegetatively Propagated Plant, the Carnation.- Somaclonal Variation in Some Cultivars of Fuchsia.- Somaclonal Variations in Tobacco.- Cellular Engineering by Means of Gamma Fusion : Genetic Variation in Fusion Products.- Nitrate Reductase-Deficient Mutants of Nicotiana Plumbaginifolia.- Valine-Resistant Plants of Nicotiana Plumbaginifolia.- Concluding Remarks.- Concluding Remarks.