GENETIC DIVERSITY AMONG VARIETIES OF POTATO (Solanum tuberosum L.) CULTIVATED IN MEXICO

In Mexico exist big diversity of potatoes (Solanum tuberosum L.), but this genetic resource is not utilized due to limited genetic information. RAPD and ISSR consensus data analysis was used to study the genetic diversity and population structure in fifteen potato cultivars (9 improved from Europe, United States of America and Mexico, and 6 Mexican landraces) grown in Mexico. Amplification with 5 decamer random primers and 5 ISSR primers generated 138 markers of which 116 (84.4 %) were polymorphic. The highest coefficient of similarity was demonstrated between Fianna and Armada cultivars which had a value of 0.89. In contrast, the lowest coefficient of similarity was obtained between Tollocan and Cambray Rosa Morelos cultivars with a value of 0.55. The high level of cultivar differentiation (G(ST) = 0.71) and low level of gene flow (N-m = 0.19) across all loci reflected that the level of genetic divergence among the fifteen cultivars was high. The molecular variance analysis revealed significant contribution of differences among regions, among type of cultivar, among populations and within populations to the total genetic diversity of potato cultivars studied.