Resumo

DELGADO VALERIO, Patricia; NUNEZ MEDRANO, Joaquín; ROCHA GRANADOS, Ma. Carmen  e  MUNOZ FLORES, H. Jesús. Genetic variation in two pine seed natural stands established in Michoacán State. Rev. mex. de cienc. forestales [online]. 2013, vol.4, n.18, pp.104-115. ISSN 2007-1132.

More than 200 seed natural stands have been established in Mexico. However, nowadays many of them are abandoned or do not have a proper management. Genetic knowledge at the molecular level of seed trees is essential for the production of better plant quality, to ensure success in reforestation and conservation of genetic resources. The central objective of this study was to assess the levels of genetic variation in two seed stands of Pinus montezumae and Pinus pseudostrobus established in the state of Michoacán, screened with five nuclear microsatellite molecular markers. Results show that P. pseudostrobus contains a greater number of alleles (A= 19) than P. montezumae (A= 18). In P. pseudostrobus, the average observed heterozygosity was higher than the expected heterozygosity (H_o= 0.290, H_e= 0.277), whereas in P. montezumae the expected heterozygosity was higher (H_o = 0.246, H_e= 0.274). However, none of the values deviate significantly from the Hardy-Weinberg equilibrium. The effective size of P. pseudostrobus was higher (N_e= 805) than that of P. montezumae (N_e= 492), with a non-significant inbreeding level (F= -0031 in P. pseudostrobus; F= 0.103 in P. montezumae). Therefore, it can be considered that there is no significant effect of consanguinity between the trees of each seed stand and those containing individuals with the gene pool representative of the two species. Finally, a proposal to obtain seeds of particular trees to each species is presented here.

Palavras-chave : Seed stand; inbreeding; heterozygosity; nuclear microsatellites; Pinus; genetic variation.

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