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Research aims to improve the quality and yield of wine grapes

Matthew Fidelibus/Extension specialist, viticulture and enology:     
My name is Matthew Fidelibus. I'm an extension specialist in the department of viticulture and enology at UC Davis.

Here at the Kearney Ag Center, we have a varied research program, but one area that we're focused on particularly is evaluating selections of traditional wine grape varieties, looking for ones that are the best suited for the climate in the San Joaquin Valley.

We're located right in the heart of the grape growing region in the San Joaquin Valley and so the conditions are just like they would be in many other important production areas.  We're adjacent to commercial vineyards and so the data that we collect here is very representative of what growers might expect to achieve in their own vineyards.

Most of the wine grapes that we grow in the region are classic wine grapes that people are accustomed to drinking wines from. For instance, cabernet sauvignon, chardonnay, merlot...and so what we're trying to do is we're looking at actually selections of those varieties. A grower might go to the nursery and find seventy different selections of chardonnay being offered.

So the question is, I want to plant chardonnay but which chardonnay do I want to plant? And so what we've been doing is actually trying to go through them as systematically as we can and compare them to like an industry standard selection. New selections that come to the US, we will evaluate them; their viticultural characteristics; how much fruit do they produce?  How many berries does each cluster have?  How compact is that berry? Cluster compactness is something that's important to us because in this warm climate, if the clusters are too compact, we tend to get rot problems.

So that's something that we look at.  So it's not only the production of how much fruit but also how good is the fruit?  Is the fruit sound?  We're also looking at the chemical composition of the fruit.  What's the sugar to acid ratio?  Those things affect the sensory properties of the wine and also the storage ability of the wine.

I think the value of having our own vineyards here at Kearney is that we have complete control over the vineyards so we're doing things in a very uniform way.  We know what's been put onto the grapes, we know how they've been managed and so we can feel very confident that the results that we have are due to variation, in this case genetics, and it's not due to some inconsistent cultural practice or something like that.

The research that we do in the Valley, it affects growers not only in the state but it affects people throughout the country and internationally. I mean the San Joaquin Valley wine grape industry historically has produced up to half of the fruit for wine in California and most of the wine grapes that are grown in the United States are grown in California. So, the production that we're having in the San Joaquin Valley, the effect that we're having on growers here has repercussions for the whole country. Our grapes and wines are shipped internationally and so it affects consumers around the world; not just growers and people locally.


Learn more about Fidelibus' findings and general viticulture information, or follow his Twitter feed.