PINUS GREGGII VAR. AUSTRALIS SEED ZONES IN HIDALGO, MÉXICO

Abstract

In order to establish seed production zones and to avoid inappropriate seed movement for operational plantations, 44 populations of Pinus greggii var. australis from the state of Hidalgo, were located and clustered based on data from nine biophysical variables. The cluster analysis geographically discriminated two major population groups. Zone I has sub-humid temperate climate with annual precipitation between 600 and 1200 mm, mean temperatures between 14 and 19 °C, at elevations from 1600 to 2700 masl and is located in western Hidalgo. Soils have predominately clay textures with average pH values of 6.6 and covered by pine, pine-oak and pine-juniper forest types. Zone II is characterized by humid-temperate and humid-semitropical climates, with annual precipitation from 1300 to 2500 mm, mean temperatures of 17 to 21.5 °C, elevations between 1 200 to 1 700 masl, and is comprised of populations located at the eastern part of the state. Soils predominately have loam and clay loam textures with pH values around 4.3, and a vegetation type of mountain-cloud forest. A further subdivision generated five subgroups for Zone I and four subgroups for Zone II, based on biophysical similarities. In restricted sense seed must be used inside each group of populations. Risk of poor adaptation, i.e. low survival or reduced productivity, increase when seed is moved among populations from different groups inside zones and much more if transference is among populations from the two zones.