Isolation and Characterization of Fifteen Microsatellite Loci for the Use in Breeding of Gmelina arborea Roxb. (Lamiaceae)

Gmelina arborea (melina) is a valuable tree species throughout tropical areas, and there are extensive commercial plantations of this species in Southeast Asia, West Africa, and Latin America. As part of a research program for the genetic improvement and management of G. arborea at Instituto Tecnólogico de Costa Rica, we developed, validated, and optimized fifteen microsatellite loci. We used 23 clones belonging to five different companies currently using clonal selection to manage their commercial plantations. Our results showed that all fifteen loci were polymorphic and together had 75 alleles (2-7 alleles/locus). We also found that eleven loci showed lower heterozygosity than expected under Hardy-Weinberg equilibrium (HWE). We calculated the genetic similarity among all clone pairs using the number of shared alleles to examine the potential of these loci for clone discrimination. Overall, pairwise similarity among clones ranged from 0.36 to 0.83, and our findings also showed that clones from the same commercial plantation tended to be more similar to each other than to clones from other plantations. These microsatellite loci will contribute toward the characterization of the genetic diversity, the identification of elite clone lines for timber production, and breeding and adequate management of commercial plantations of G. arborea.