Allele-based modeling to predict phenological stages of grapevine hybrids under future climatic conditions.

The integration of genetic values in ecophysiological models for phenological stages allows us to predict the effect of loci in future conditions. Modern grapevine (Vitis vinifera L.) breeding programs aim to create new varieties resistant to biotic and abiotic stresses, simultaneously. Developmental stages may affect many physiological processes in grapevine, especially berry composition. The shifts of phenological stages observed in the context of climate change challenge the selection of new varieties. In this paper, we evaluate how genotypes derived from a breeding program aimed at developing disease-resistant varieties may adapt to future climatic conditions. Specifically, we examine the genetic variability of three key phenological periods (February 15 to budbreak, budbreak to flowering, and flowering to véraison) using an ecophysiological model based on thermal requirements. Using high-density genetic information, we identified more than 18 quantitative trait loci for three phenological periods. By combining relevant allelic effects, we virtually constructed both an early and late composite genotype and evaluated their potential adaptation to future climatic conditions, using the greenhouse gas IPCC emissions scenario RCP 8.5 and simulated meteorological data at a local scale. While the early composite genotype may not outperform V. vinifera cv. Chardonnay under these projected conditions, the late composite genotype appears to remain suitably adapted through at least 2060. Our approach enables the prediction of allele-specific advantages on phenological stages across a range of future climate scenarios.