Genetic diversity among pepper (Capsicum spp.) accessions estimated by microsatellite markers
It is essential that the genetic variability of preserved accessions germplasm banks be evaluated and quantified, which allows, for example, the detection of duplicates, generating more reliable data, especially for groups of plants that have a wide genetic variability, as in the case of the Capsicum genus. . We examined the DNA from the leaves of nine accessions of Capsicum spp . from the Federal University of Maranhão Germplasm Bank. Amplification was performed using 78 microsatellite primers previously described as potential molecular markers for Capsicum accessions. Thirty-three microsatellite primers produced amplification products, seven of which were polymorphic and used to investigate genetic variability among nine accessions. The proportion of polymorphic loci in pepper accessions was estimated at 21%. A mean of 2.28 alleles was detected per polymorphic locus and the number of alleles ranged from 1 to 3. The highest effective number of alleles was 1.62, and the highest values of mean observed heterozygosity (Ho) and Shannon's diversity index (I) were 0.533 and 0.421, respectively. Private alleles were detected in two accessions: UFMA17 and UFMA35. The highest Ho value was found in the UFMA10 accession, whereas the lowest value was recorded in the UFMA35 accession. Fixation indices (FST) indicated that 65% of the total allele frequency variation occurred within the analyzed loci. The polymorphism information content ranged from 0.011 to 0.354. Clustering of samples based on Nei's genetic distance matrix revealed the formation of three genetically distinct groups that allowed identifying genetically distinct groups based on SSR markers and discriminating the most closely related accessions of Capsicum spp. Neighbor-joining cluster analysis and PCoA allowed identifying genetically distinct groups based on SSR markers and discriminating the most closely related accessions of Capsicum spp.