Molecular characterization of Melanoxylon brauna (Fabaceae) matrices established in a multiclonal minigarden

Abstract

Melanoxylon brauna is a tree species native to the Atlantic Forest that has great potential for reforestation and urban afforestation. Due to its exploitation, germination difficulties, and absence in afforestation projects, it is currently endangered. Therefore, this study aims to evaluate the diversity and genetic structure in M. brauna matrixes established in multiclonal minigardens through inter simple sequence repeat (ISSR) markers. Plant material of 59 individuals arranged in the multiclonal minigarden was collected for the analyses. Eleven ISSR primers were selected, which generated 183 fragments, among which 117 were polymorphic (63,93%). The efficiency of the markers was confirmed through the polymorphism information content (PIC) which resulted in an average value of 0.36, characterizing them as moderately informative. High genetic diversity was found based on the values of the number of observed alleles (A_O = 2.00) and effective alleles (A_E = 1.63), Nei's diversity index (H* = 0.36), Shannon index (I* = 0.54), and the formation of distinct groups by cluster analysis. Despite the alleles being well distributed among individuals, revealing high genetic diversity, Bayesian inference revealed only one genetic group (K = 1). The ISSR markers proved to be efficient in the characterization of the genetic diversity in M. brauna individuals, and the population of the multiclonal minigarden can be used as a source of propagules for seedling production. However, actions such as the expansion of the genetic diversity through the introduction of plants from different origins can increase the adaptive potential of the minigarden and future established populations.