XVI International Botanical Congess

Rich diversity of biological and commercial characters in wild and cultivated potato species of South America is a result of the existing variability of ecological environments in their habitat. We developed differentiation maps showing distribution of potato species and compared them with agriclimatic conditions of this continent, which made it possible to explain the origin of these or those characters of importance for potato breeding. For example, species of the series Acaulia, Megistraeroloba etc. the habitats of which reach the altitudes of 3900-4700 m above sea level where mean annual temperatures do not exceed 7Â? C, are characterized by high resistance to low temperatures. Dry Alpine areas harbour such potato species that carry genes of resistance to arid soils and dry air (series Cuneoalata). The species (series Conicibaccata) occurring in Colombia and on the eastern Andean slopes, the zone of unceasing fogs and rains, have adapted to the conditions of excessive humidity. The impact of ecological environments is also observed in tuber quality and resistance to diseases and pests typical of the areas and environments favourable for their breakout and spreading.