Genetic Diversity and Structure in a Spanish Grape Germplasm Collection Assessed by SSR Markers

Background and Aims. Vitis vinifera L. is a major global horticulture crop which holds historical connections contributing to the development of human culture. The main objective of the study was to explore the genetic diversity and structure of grapes curated at the germplasm bank of Aragón and link them to cultivar utilization, putative geographic origin, and historical events. Methods and Results. The genetic diversity of the 411 accessions of the Grapevine Germplasm Bank was assessed using 26 SSR markers. SSR markers VVIP31, VMC4F3-1, VVIV67, and VVS2 distinguished the 156 nonredundant genotypes found in the collection. The profiles were compared to the El Encin database, and 105 were identified as known cultivars, of which 93 were Spanish, 12 were from other European origins, and 51 others were not known. The 51 profiles, as they were all collected in Spain, were designated as Spanish unknown for further analysis. To establish a comparative study for principal coordinate analysis (PCoA) and structure, we kept 113 identified genotypes from this collection but added 61 representative genotypes with diverse European and oriental origins. Bayesian analysis and PCoA showed four distinct groups of grape cultivars: (1) traditional Spanish wine grape from Aragón or cultivated along the Ebro River, (2) Spanish wine grape, (3) Spanish and oriental table grape, and (4) Italian, Portuguese, French, and German-Slovenian wine grape varieties. Conclusions. The 51 unknown Spanish genotypes were not registered yet in any European commercial list and are of special interest. These genotypes could be ancient cultivars adapted to local climatic and environmental conditions and probably resilient to face the new conditions derived from climate change.