Genetic Diversity Assessment of Wild Southeastern American Vaccinium using Microsatellite Markers

The United States Department of Agriculture (USDA)-Agricultural Research Service (ARS)-National Clonal Germplasm Repository (NCGR) in Corvallis Oregon preserves genetic resources of more than 1700 Vaccinium accessions from 33 countries. Wild Vaccinium species from northwestern, central and south Florida and neighboring US states were collected in multiple USDA expeditions and are being preserved at the NCGR-Corvallis. This invaluable germplasm is vulnerable to loss in the wild due to encroachment of human development. The objective of this study was to evaluate genetic diversity in 67 accessions from these southeastern US expeditions. More than 44 simple sequence repeats (SSRs) developed in V. corymbosum were used to screen 14 accessions of four species for polymorphism. Fourteen SSRs proved polymorphic and easy to score in these species and were used to estimate genetic diversity of the 67 individuals including 19 V. elliottii, 12 V. fuscatum, 1 V. myrsinites, and 35 V. darrowii accessions. Genetic distance was closest among the two named cultivars: V. darrowii ‘Everblue’ and ‘Johnblue’. Vaccinium darrowii Florida 4B, a well-known breeder selection used for introducing the economically valuable low chilling trait into the cultivated highbush blueberry gene pool, was obtained from two sources. Unfortunately, the two Florida 4B samples had different fingerprints. Two accessions of V. darrowii with different New Jersey selection numbers had identical fingerprints. Cluster analysis separated the wild accessions into species groups. Future analyses will include confirming the identity of the Florida 4B genotypes and evaluating the genetic diversity and population structure of these wild accessions.