XVI International Botanical Congess

Key words: Phytophthora infestans, late blight, Solanum tuberosum, in vitro selection, culture filtrate. In the incidence of disease on the potato crop, the late blight caused by the fungus Phytophthora infestans is notably marked. In this work we carried out experiments to evaluate the parameters for the in vitro selection of potato seedlings with the culture filtrate of the pathogen and it was explore the possibility of using this methodology in the varietal selection of new resistant mutans lines. The strain of the pathogen 1,2,3,4,6,7,8,9,11 genes were characterized and for the liquid culture it was analyzed the composition medium and incubation time, and for the culture filtrate we analyzed concentration and thermostability. In order to evaluate all these parameters we use roots inmersion method from vitroplants of the potatoes varieties Diacol Capiro and Diacol Monserrrate, which are reported susceptible and resistant respectably. According to the parameters evaluated the best fungi growth was reached with MS medium modified by Dieter (1986) at 20th day after culture under 21?C and constant darkness. Thermostability in the culture filtrate and best dilution for the selection was found at 47 ml/100ml.