Mankind, throughout history, has strived to improve his food sources. By means of slow and empirical selections, it has been possible to greatly increase both quantity and quality of plant crops. This procedure has brought the most useful cereals to a state of refinement that seems to be difficult to further improve by the same methodology. Indeed, natural sexual mechanisms were always used to cross closely related sexually and genetically compatible organisms; the selection procedure consisted of isolating the most promi­ sing progenies. Obviously, by this way, plants could only share preexisting genetic pools. On the other hand, the last decade has seen drastic modifi­ cations of the experimental plant sciences, with the appearance of new technological possibilities. Because of this profound reshaping of our experimental ap­ proaches, other means can now be realistically envisaged in order to achieve similar or even higher goals. It is, for instance, possible to attempt completing sexual crosses (where both male and female gametes bring together the genetic informations necessary for growth and development of the offspring) by parasexual means by which novel genetic informa­ tions could possibly be added to the heritage •. At the limit, such genetic manipulations could enable man to create plants capable of producing new substances characteris­ tic of unrelated plants or, more generally, of other living or­ ganisms. Even if these possibilities might appear quite remote, the interest of Scientists has been awaken and, indeed, several at­ tempts to such genetic manipulations have already been made.