Grape berry uniformity in the vineyard is often considered a hallmark of consistency in wine quality, and it may be especially important to the production of high quality red wines like Pinot noir. Growers often employ cultural practices such as cluster (or cluster part) thinning to achieve greater evenness of fruit maturity at harvest.
Genetic composition and mechanisms reside at the most fundamental level of understanding how grapevines function. Toward this end, Dr. Laurent Deluc and his team hope to determine some aspects of the genetic control responsible for the grape ripening process. The ripening initiation (véraison) is under a coordinated genetic and environmental control and is critical in determining the fruit composition towards harvest. Using a research grant from the Oregon Wine Board, Dr. Laurent Deluc’s lab at Oregon State University has identified one potential “master regulator,” namely Auxin-Responsive Factor 4 (ARF4), which is associated with the timing of ripening initiation in grape berries. This research project aims to characterize ARF4 to understand not only the influence of ARF4 in the timing of ripening initiation, but also its direct or indirect influence on fruit quality aspects.
Working with international collaborators, Deluc has adopted the microvine model to advance his research. This special vine was developed using a natural mutant of Pinot Meunier with a short flowering cycle and stature, and using Agrobacterium it can be transformed into alternate genotypes, thus speeding up the breeding process.
By identifying the plant growth regulators that govern the initiation of fruit ripening it may eventually be possible to develop practices that will improve fruit composition under varying environmental conditions due to climate change. This could be a major advance in viticulture technology that will be useful in both cool and warm growing regions.
You can read more about Dr. Deluc’s research in the OWRI technical newsletter, view a seminar by his graduate student Ms. Amanda Vondras titled Time of Flowering and Seed Contribution to Variable Entry of Pinot Noir Berries into the Ripening Phase, or view a seminar by Dr. Simone Castellarin from the University of British Columbia titled Using Molecular Viticulture to Understand and Manage Grape Ripening.