Genetic diversity of Syagrus coronata and principal component analysis of phenotypic traits: a palm from the brazilian semiarid biome

Syagrus coronata (Arecaceae) is among the endemic species of Caatinga, a unique and fragile Brazilian biome. This palm has ecological and socioeconomic significance since its seeds have high oil and protein contents. Although the species is not under threat, it is in a vulnerable position due to intense exploitation and severe biome fragmentation. Natural populations of S. coronata are found in the Caatinga remnant areas, including those located in Northern Minas Gerais. In this region, they occupy an ecotone, which enables potential diversity of this species given the different environmental pressures. To test this possibility, sets of genotypes from three locations were analyzed in terms of their morphometric traits. In general, Pearson’s correlation analysis indicated weak interaction between vegetative and reproductive traits. The high positive correlations found for vegetative traits may be because most of them are leaf-related features. A Mantel test indicated a weak linear relationship between the two groups of variables and, thus, a weak correspondence among the genetic clusters. The genotypes were arranged into several different groups by both the Tocher and UPGMA methods, which revealed considerable variability and dissimilarity regardless of their provenance. Visual inspection of the principal component analysis results indicated that the genotypes were categorized into one large group and numerous medium to small groups. The PCA results were also used to determine which morphological descriptors should be discarded due to their low contributions. This preliminary information can help genetic programs for the conservation and breeding of S. coronata.