Ability of morphological traits from needles and cones to identify Pinus pseudostrobus Lindl. varieties

Introduction: Pinus pseudostrobus, a species of ecological and economic importance in Mexico, has a wide distribution and intraspecific variation, which generates controversy regarding the identification of its operational taxonomic units (OTU).Objectives: To evaluate morphological traits of cones and needles of P. pseudostrobus to distinguish varieties and identify traits with greater discriminatory capacity.Materials and methods: Twelve traits in cones and 20 in needles were measured on samples from 153 trees identified in four putative OTU. Univariate and multivariate ANOVA, variance component estimation and canonical discrimination analysis (CDA) with cross-validation were carried out.Results and discussion: Thirteen needle and 12 cone traits showed significant differences between OTU. The variance between OTU increased 6.8 %, on average, when considering the varieties oaxacana and apulcensis as distinct OTU. Multivariate analysis confirmed significant differences in foliage and cones between OTU. The variation explained by the CDA increased from 0.35 to 0.74 and 0.76 when using foliage, cones, and overall variables, respectively. Eight cone traits allowed discrimination among OTU with average error of 9.2 %.Conclusions: Despite the wide intraspecific variation, it was possible to differentiate the main OTU of P. pseudostrobus with cone morphological markers, with important implications for a better management of genetic resources of this species. The present study shows evidence of morphoanatomical differences between oaxacana and apulcensis varieties.