Genetic diversity among accessions of Spondias mombin L. collected in northeastern Brazil

Abstract

Spondias mombin is an arboreal species, the fruits of which possess a unique flavor and aroma and contain both nutritive and bioactive compounds. Considering that knowledge regarding the genetic variability in S. mombin is important for the establishment of a genetic improvement program, the aim was to characterize S. mombin accessions collected in the states of Maranhão and Piauí, northeastern Brazil, using molecular analysis with simple sequence repeats markers (ISSR). Twenty-six accessions maintained in the Embrapa Meio-Norte germplasm bank (Teresina, PI, Brazil) and two dwarf accessions collected from a private property in Teresina-PI were evaluated. The 12 ISSR markers employed presented strong discriminatory power as demonstrated by the high percentage of polymorphism (88.75%) and mean polymorphic information content (0.641). High genetic diversity among the accessions was demonstrated by the diversity indices of Nei (H=0.37) and Shannon (I=0.55), while gene flow between populations was considered moderate (Nm=0.6268 migrants per generation). The genetic diversity could be explained mainly by variability within-populations (88.71%) rather than between-populations (11.29%), although the genetic differentiation coefficient between-populations was moderate (GST=0.11) and statistically significant (P < 0.01). Unweighted pair group method with arithmetic mean (UPGMA) clustering and Population Structure analysis showed genetically distinct groups. The dwarf accessions were the most divergent and should be incorporated into the germplasm bank. Our study verified the existence of genetic differentiation between the tested S. mombin accessions and confirmed that such variability could be exploited through genetic improvement programs.