Genetic variability in natural populations of agave durangensis (agavaceae) revealed by morphological and molecular traits

Agave durangensis is an endemic species that occurs in a reduced area in southern Durango and northern Zacatecas, Mexico. We analyzed the genetic variability of three populations of the species using two pairs of Inverse-Sequence-Tagged-Repeat primers and nine morphological characters to determine the species of the morphologically variable populations. The primers generated characteristic amplification profiles, which distinguished between populations of A. durangensis and revealed interspecific variability when compared with individuals of A. asperrima. Some incongruence between morphological and molecular variability was detected. High genetic variability was indicated by an elevated level of polymorphism (24.18-61.50%) among 91 genetic loci amplified and by the level of gene diversity (0.0807-0.2337) among populations. Genetic differentiation (0.0328-0.4857), gene flow (0.5294-14.7511), genetic distance (0.0200-0.3019), and genetic identity (0.7653-0.9802) among populations suggested that one of the three populations of A. durangensis is in a present advanced diversification process but may still maintain some level of gene flow with the other two populations. Urgent conservation efforts, including protection from harvest, should be addressed for maintaining the genetic variability of the natural populations of A. durangensis.