Variación y Tipos de Diferenciación en Poblaciones de Roble (Nothofagus Obliqua (Mirb.) Oerst.)

Abstract

Variation and genecological differentiation in populations of Robl e (Nothofagus obliqua (Mirb.) Oerst. wer e analyzed along latitudinal and altitudinal transects in the mediterranean zone of it distribution. Th e tw o morphological characteristics of the species used for the analysis, because of their lo w susceptibility to modification by einviromental variation and greate r significance from the point of view of separatinraces, wer e seed weigh t (size ) and number of stamens per mal e flower. Th e analysis wa s also based on consideration of physiological characteristics, germinative capacity and germinative value in response to different periods of stratification.
Analysis of variance and a multiple comparison test wer e used for assessing differences among populations and treatments. A two-dimensional (latitudinal and altitudinal) clinal variation wa s determined for the Robl e populations using correlation coeficients obtained by effecting regression analysis for the characteristics mesured an latitude, altitude and climatic factors sucht as average annual precipitation, average annual temperature and precipitation during the growin g season.
Neverthless, physiological responses as well as the variation in the northern part of ist range suggests the ver y likely development of ecotypes and definitively a mixtur e of continuos (clinal) and discontinuos (ecotypic ) variation in Roble .