Molecular Analysis by Microsatellite Markers of Goji Plants (Lycium barbarum L.) Grown in Central Italy Reveal Genetic Distinction from Both L. barbarum and L. chinense Species

Lycium barbarum L. is a shrub native to China. It produces berries that are high in nutraceutical value. Its commercial appeal has led to the development of new plantations in Italy over recent decades. The majority of cultivated goji plants are derived from local nursery seedlings without the selection of varieties or clones. This study used nine simple sequence repeats (SSRs) from Lycium chinense L. to analyze the genetic structure and variability of heterogeneous, seed-derived accessions cultivated in an orchard located in central Italy (from here on referred to as field). The results were compared to accessions of known origin (LB, Lycium barbarum; LC, Lycium chinense). The study aimed to determine the genetic origin of seedlings and assess the feasibility of using microsatellite markers for individual fingerprinting. It also aimed to propagate the most adapted, productive plants while ensuring traceability and protection of potential clones throughout the production chain. The SSR markers used revealed that the field accessions were genetically distinct from both the L. barbarum and L. chinense accessions, whose seeds came from different European Botanical Gardens. The mean observed heterozygosity (Ho) across the three groups was 0.356, higher than the mean expected heterozygosity (He) of 0.314. The values of the inbreeding coefficient (FIS) ranged from −0.25 (field) to 0.05 (LC), confirming the high genetic variability in our dataset. The fixation index (FST) was 0.234, indicating medium to high genetic differentiation. The Bayesian analysis revealed three distinct clusters, indicating that three gene pools influenced the genetic structure of the studied populations. The orchard accessions form a distinct population, most likely a L. barbarum landrace, descended from two distinct ancestral populations that differ from the two known species. Our findings preliminarily lay the groundwork for the protection of some clonal lines of goji accessions for use in future planting more suited to the Mediterranean climate. This study also serves as a foundation for a more thorough characterization of cultivated L. barbarum, allowing for traceability and sustainable management of the genetic resource.