Classification of varieties for their timing of flowering and veraison using a modelling approach: A case study for the grapevine species Vitis vinifera L.

Understanding differences in phenology for varieties of a given species is important for making informed decisions on variety choice in the context of climate change and breeding new cultivars. Phenological models that incorporate temperature as a key environmental factor can be used to describe the differences in phenological timing between cultivars. This paper outlines a methodology, based on a phenological model, for classifying the timing of flowering and veraison for a substantial number of varieties of the grapevine (Vitis vinifera L.). 95 varieties were characterized for flowering and 104 varieties for veraison. Various statistical measures were used to assess the performance and predictions of the model at the varietal level: model efficiency, root mean squared error and confidence intervals. The methodology might be used to understand varietal differences for other species in future studies. Model outputs can be used in combination with predicted climate change scenarios to assess the suitability of varieties under climate conditions of the future.