Six potential potato cultivars with late blight (Phytophtora infestans) resistance in Bolivia

Potato late blight (Phytophthora infestans) has become a serious problem all over the potato growing regions of Bolivia. This disease causes great losses ¡n production, affecting up to 100% of the crop if no control measure is applied. For an effective control of late blight several fungicide applications are needed and in some cases more than ten are required during the entire cultivation cycle. During the past five years the National Potato Research Program (PROINPA) has been selecting clones with resistance to this disease. These clones were supplied by the International Potato Center (CIP) and the Colombian Agricultural! Institute (ICA). From the original population of approximately 300, clones have been annually evaluated and selected for their late blight resistance, high yield and good agronomic characters. As a result, the six best clones were selected for their performance in relation to the above-mentional factors during five years of evaluation. In order to measure the damage caused by late blight, the international evaluation scale provided by CIP (1 = 0% damage to 9 = 97-100% damage) was used. Thus, ¡t served to estimate the AUDPC (Area Under Disease Progress Curve), which together with yield and culinary quality determined the selection of six potential varieties with the active participation of farmers and scientists in the areas where testing was performed. Moreover, the nutrient content and the glycoalkaloid level of the clones were determined. The glykoalkaloid level in the variety Robusta, cultivated in two contrasting conditions, was also evaluated.