NATURAL REGENERATION OF Aspidosperma quebracho blanco Schltdl IN NATURAL FORESTS OF DRY CHACO (SAN LUIS, ARGENTINA)

CIUFFO, GM; MORALES, A; CIUFFO, LEC

Merlo, SL

Congreso; XXXV Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2017

Soc. de Biol. de Cuyo

The natural regeneration of A. quebracho blanco in Dry Chaco natural forest is based on two strategies, vegetative and sexual. We evaluated the genetic structure of the population and relatedness between adults and young with the aim to estimate if A. quebracho blanco reproducesfrom sexual or vegetative strategy. Regeneration was defined as trees with a height equal to or greater than 25 cm and a DAP less than 7 cm distant maximum 10 m from the adult tree.The genetic structure was analyzed by molecular markers RAPDs. Exemplars of A. quebracho blancofrom two fragments of Prosopis flexuosa forest, located in San Jerónimo (SJ) and Las Chacras (LCH), Dry Chaco, were studied. Regarding the population genetic structure, we observed higher polymorphism in SJ (72.29%) than in LCH (61.45%). AMOVA analysis of the RAPDs patternevidenced a high intra-population (82%) and lowers inter-population (18%) variation. Threedifferent analysis were performed: UPGMA cluster analysis by using DICE coefficient; principal coordinate analysis; and cluster analysis using Nei´s genetic distance. All of them support the presence of two populations genetically different, each of them with subpopulations. Thecoefficient of genetic differentiation (GST) provides similar results. In SJ population predominates the genetic flow (Nm), while for LCH (Nm=0.51) the genetic drift predominates. Considering the reproductive mechanism, the present results support the hypothesis that the youngs comes from seeds (sexual reproduction), since from the 29 individuals evaluated in the two fragments, at none case the genetic distance was equal to 0 (zero) with the adult individual.