Plant domestication is stimulated by economic demands. Crop plant formation is controlled primarily by natural selection in cultivation; artificial selection is only a useful addition. The ecotypical nature of the initial material has great bearing on the success of domestication. The weeds of a convergent group were well adapted to being cultivated; weeds of a divergent group can be domesticated only with difficulty. Wild plants in nature are extremely varied ecotypically: some can be domesticated easily, others with difficulty. Some wild plants and weeds can be cultivated without genetic change (naturalization), while a genetic transmutation is necessary for the domestication of others (acclimatization). New domesticated ecotypes can be produced: 1. as a result of reconstruction of the initial populations and new ecotype synthesis on the basis of individual genotypes; 2. by means of hybridization of wild or weed initial genotypes with cultivated ones; 3. by use of new mutations in cultivation and further plant breeding.