Genetic variation in needle epicuticular wax characteristics in Pinus pinceana seedlings

Abstract

Seedlings from each of 12 Pinus pinceana populations from throughout the species' range in Mexico were evaluated in a common-garden test to (1) determine the level of genetic variation and genetic structure of epicuticular needle wax quantity, (2) examine differences in wax chemical composition, and (3) seek evidence for an adaptive response in wax composition and quantity across environmental and geographic gradients. Regions and populations within regions showed high variation (38.2% and 10.5%, respectively, of the total variation) in wax quantity. Epicuticular wax recovered from primary needles of P. pinceana comprised eight classes. Secondary alcohols (71.7%) were the major homologs identified by gas chromatography. Seedlings from the northern region were separated based on wax composition from seedlings from the central and southern regions by canonical discriminant analysis. A strong differentiation among regions (Q STR=0.571) and populations within regions (Q STP(R)=0.384) was observed for wax quantity. Data on wax quantity and chemical composition indicate that physicochemical characteristics of epicuticular wax may show adaptation of P. pinceana to local environments.