Population genetic structure and mating system of Swietenia macrophylla King (Meliaceae) in the Brazilian Amazon : implications for conservation

Mahogany, Swietenia macrophylla (Meliaceae) is the most valuable hardwood species in Neotropics and is seriously threatened owing to over-exploitation and habitat destruction. The population genetic structure and mating system of S. macrophylla were studied in the Brazilian Amazon for conservation purposes. Ten highly polymorphic micro satellite markers were developed from an enriched genomic library of S. macrophylla and combined in three multiplexed fluorescence based genotyping systems. The number of alleles per locus ranged from 11 to 25 (mean = 15.8). The probability of genetic identity (7x10- 15) and the probability of paternity exclusion (0.999998) found over all loci indicate the high discriminating power of these markers. The genetic structure was investigated in seven populations 8- 2,103 km apart. High genetic diversity was detected within populations (mean He = 0.761, range 0.719-0.800) and a significant level of inbreeding was found (f = 0.046, P<0.0001, range 0.014-0.097) indicating nonrandom mating of individuals within populations. Genetic differentiation among populations was significant (A = 0.12 and p = 0.14, P