Resumo

VIVEROS-VIVEROS, Héctor et al. Isoenzymatic variation of Pinus hartwegii Lindl. along an altitudinal gradient in Michoacan, Mexico. Agrociencia [online]. 2010, vol.44, n.6, pp.723-733. ISSN 2521-9766.

To determine the genetic variation along an altitudinal gradient and generate guidelines for the conservation of Pinus hartwegii Lindl., genetic isoenzymatic variation was studied in populations of the species at different altitudes in Pico de Tancítaro National Park, Michoacán, México. Seeds were collected from four locations at altitudes of 3000, 3200, 3400 and 3600 m. Polymorphism was found in 11 of the 12 loci examined. The expected average heterozygosity (H_e) was 0.12. At three loci there was Hardy-Weinberg non equilibrium (p<0.05), with a deficit of heterozygotes. Genetic differentiation among populations was significant (F_ST=0.111). Average genetic distance (0.108) was low, and gene flow was relatively low (N_m=2.0). Grouping populations separated the 3600 m population from the other three (3000 to 3400 m) (p<0.05). It is recommended that a forest genetic resource conservation unit be established at an altitude of 3600 m with a minimum viable population size (N_e) of 4157 individuals, while another should be established between 3000 and 3350 m with N_e of 3055 trees.

Palavras-chave : Pinus hartwegii; genetic resource conservation; genetic differentiation; gene flow; isoenzymes; genetic variation.