Until recent years, plant genetic was involved in heredity studies through the analysis of segregations in progenies after crossing. New potentiality arose as genetic tools with the use of dissociated plant elements, transforming and cultivating them in vitro. When plants are regenerated from manipulated tissues, new structures of varieties (clones) new genotypes (transgenic plants) and new regulations of genes expression (vitrovariants) open new ways for plant genetic engineering. Progressively these technological tools are integrated in the methods of plant breeding. Yet all possible consequences of these new types of heredity and of these new genetic structures must be evaluated. As first priority the analysis of possible incidences in the field of food, nutrition and health gives the basis for diagnostics and organisations aiming to avoid the release of genotypes which could have unwanted effects.