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Phenetic analysis in Psidium (Myrtaceae) species from Venezuela

Abstract:

Psidium (Myrtaceae) has been a genus with difficulties in the limits among the species. This situation demands the need of research using different kinds of information that will be also useful in solving the systematic relationships among its members. Phenetic or numerical classification approach has been used to order taxa based on global or total similarity among organisms according to the characters used in the study. The objective of this research was to carry out a phenetic analysis on Psidium species of Venezuela. The research included 44 individuals of P. acutangulum, P. guajava, P. guineense, P. maribense, P. salutare, P. sartorianum and Calycolpus moritzianus. The analysis included 46 variables, of which 15 were morphological, 26 anatomical and five phytochemical. The data matrix was processed using cluster analysis (CA) and principal components analysis (PCA); for the qualitative variables a frequency analysis was used. The results showed that three groups of species were formed using CA, whereas the PCA selected 13 of the total number of quantitative characters to explain this arrangement. Based on the frequency analysis, the most determinant qualitative variables were: number of paired nerves, type of inflorescence, number of subepidermal strata, and degree of the spongy parenchyma differentiation. The variables selected were considered for describing the species studied, which contributed at the same time to determine the degree of morphological, anatomical and phytochemical similarity among the species.