Past grapes, present insights: an investigation of grape use in Roman north-eastern Iberia using geometric modern morphometrics (GMM)

The cultivation and uses of Vitis vinifera L. (grapevine) during the Roman period are known from both ancient sources and archaeobotany, in which various methods have been used to distinguish between wild and domesticated subspecies. The present analysis uses Geometric Modern Morphometrics (GMM), taking as a case study the Roman town of Iesso (modern Guissona, Catalonia, Spain) to shed new light to these issues. Five wells dated from the first century bce to the fifth century ce with waterlogged material were excavated in Guissona, from which a large number of grape pips have been recovered and studied to identify whether the grapes were wild or domesticated, as well as which of the distinct groups of domesticated varieties. The results of this study indicated a significant number of wild type grapes, which are explained by the climatic conditions at this time, which may have prompted the inhabitants of the area to grow grapevines with genotypes closely related to the hardier wild subspecies, together with the market demand of the period and local taste preferences. Finally, among the domesticated grapes identified from Guissona, varieties suitable for wine making appear to be predominant, with the Balkan variety group being the most common.