Chromosome studies in species of Eugenia, Myrciaria and Plinia (Myrtaceae) from south-eastern Brazil

Abstract

The chromosome numbers of Brazilian species of Myrtaceae were reassessed in the context of chromosomal evolution in fleshy-fruited Myrteae. The chromosome numbers of 14 species of Eugenia , three of Myrciaria and two of Plinia were determined, 14 of which had not been published before. In Eugenia , a diploid state (2 n = 22) was found in nine species, polyploid (2 n = 33 or 2 n = 44) in three species, and both diploid and polyploid cytotypes in another three species. The percentage of Eugenia species with a known chromosome number increased from 19 to 31 species, 22.6% of which were polyploid (3 triploid, 1 tetraploid and 3 hexaploid) and afurther 16.1% either dysploid from the triploid level or had both diploid and polyploid races, giving a total of 38.7%in which polyploidy is recorded. In Myrciaria (3 species) and Plinia (2 species), the chromosome number was2 n = 22, with no polyploidy known in these genera. The results reinforce the previous indications that polyploidyis of great importance in the evolution of fleshy-fruited Myrteae