GENETIC STRUCTURE OF Pinus cembroides POPULATIONS FROM CENTRAL MEXICO

Abstract

Pinus cembroides is the pinyon pine with the widest distribution and the greatest economic and social importance in México. The objective of this study was to evaluate the levels and patterns of genetic variation of eight populations of P. cembroides from the central region of Mexico by using ISSR (Inter-simple sequence repeat) markers. The populations are distributed in two physiographic provinces, the Sierra Madre Oriental and the Central Plateau. The primers used generated a total of 154 bands, of which 88.3 % were polymorphic, at the level of species. The average genetic diversity in the population was high (He = 0.22), the average polymorphism percentage was 59.2 %. The parameters of genetic diversity were higher in the populations of the Sierra Madre Oriental. Most of the genetic diversity was found within the populations (74 %) and only 26 % among them. According to the value of G_ST = 0.28, there is high differentiation between populations. The gene flow level, considered as the number of migrating individuals, was low (N_m = 1.27) between the population in the two regions. A low, yet significant correlation was found between the geographical distance and the genetic distance of populations in the two regions.