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The combination of traits of economic interest in new potato cultivars, such as resistance to late blight, viral diseases, and culinary quality are important to achieve their adoption by farmers. In the present work, molecular markers were used to identify regions associated to late blight, the viruses PVY and PLRV resistance, in 50 materials belonging to the National Institute of Agricultural Research (INIA-Venezuela): commercial cultivars, differentials of blight, advanced clones from CIP and hybrids from the Fundación PROINPA of Bolivia. DNA extraction was carried out from vitroplants and known microsatellite, SCAR and CAPS molecular markers were used. Among 96 to 26% of the accessions amplified regions of the QTL tbr of chromosome XII, associated with resistance to blight. Only the differential R9 and crc2/P8 from PROINPA amplified the R1 gene region. Between 18 and 68% of the genotypes presented the regions associated with the PVY and PLRV resistance genes (Ryadg and N genes), respectively; only 10% amplified both regions; while in 24% these genes were not detected, among them are the commercial varieties Granola, Andinita and Cartayita. This study generated valuable information to support genebank curators and breeders in potato genetic improvement programs of this country.

The cultivar Red Maradol native of Cuba, has morphological and agronomic features superior to local cultivars and adapted to soils and climates of Venezuela; that is why it is grown in a greater proportion and has been widely accepted by farmers, traders and consumers. However, the lack of availability and high cost of imported seeds limit its expansion in the country. The aim of this work was to select andromonoecious plants from different sources and locations, based on morphological and agronomic characteristics, and produce good quality seeds by self-pollinations. The characteristics for selection were based on those of the cultivar, such as: beginning of flowering between 3 and 4 months after transplant to the field, height of flowering less than or equal to 80 cm, beginning of fruiting before 4 months, height of plants less than 2 m, among others features. Selected plants showed low percentage of sterility, 30 and 64 fruits.plant-1, fruit weights between 1.4 to 1.7 kg, and estimated yields between 42.5 and 98.50 kg.plant-1 yields. Regarding fruit quality, they were elongated and smooth, wide orange-red color pulp. These populations are considered the basis for the production of good quality seeds, to continue the process of selection of more productive pure lines and hybrids.