Grape varieties you’ve never heard of could be a key to boosting already robust sales of wine grapes out of the central San Joaquin Valley.

Those grapes – 55 different varieties from places like Italy, France, Portugal, Spain and Croatia – could be blended into more familiar wines to improve color, taste and other characteristics.

Research into those varieties at the Kearney Agricultural Center at Parlier, Calif., was among topics at Grape Day 2011 that also included looks at the effect of the canopy on shading and water use, development of new grape rootstocks resistant to nematodes, an inside-the-vine look at water use, trapping and baiting for gopher control in vineyards, the importance of weed free periods in vineyard development, and the fruitfulness of dried-on-the-vine raisin grapes.

“These are probably not going to be stand-alone varieties,” said Jim Wolpert, viticulture Extension specialist with the University of California, Davis, referring to varieties with names like Schioppettino from Italy, Prieto Picudo from Spain and Viozinho from Portugal.

In short, he said, they’re not about to displace such mainstays as Cabernet Sauvignon, Merlot and Zinfandel.

“The public drinks major varieties,” Wolpert said. “Let’s respect that.”

But many varieties being tested at Kearney could be important in adding nuances of color, flavor, tannin, varietal character, structure and other qualities.

“This is not a horse race,” Wolpert said. “It’s not about winners and everybody else is a loser. Everybody can be a winner.”

Only plant material that has passed through a virus screening and identification process at Foundation Plant Services at UC Davis is being evaluated.

During the workshop, participants were introduced to new technology aimed at providing more information. They were able to use smart phones to read ‘quick response’ codes affixed to various vines and elsewhere. The barcode-like symbols then gave them more information, Web links for additional data or contact information.

Other topics presented included:

Using a solar-powered device called the ‘Paso Panel’ to measure areas shaded by the canopy of a grapevine in order to estimate irrigation crop coefficients.

Mark Battany, viticulture and soils farm adviser with UC in San Luis Obispo and Santa Barbara counties, said the panels should also be combined with soil moisture and plant based measurements to get a picture of watering needs.

He explained that the devices, which can be made for less than $500, measure shade in the vineyard at midday by showing if there is a lessening of electrical current. Then the data acquired can be plugged into a formula to calculate the irrigation crop coefficient. He said the information acquired is more precise than if generic information were used for a given crop rather than site-specific information if climate based irrigation scheduling is used.

Battany cautioned that measurements must be taken on a clear day. Passing clouds can cause problems, given that a reference reading is taken with no clouds present.

He said the devices are a good way to assess vine growth and health as well as how to manage irrigation.

The devices need to be held uniformly level and the solar pane surface needs to be kept free of dust and debris. Multiple readings should be taken quickly within the vineyard.

Battany said that as he works alone he uses a digital voice recorder with a clip on microphone to record all readings verbally. After finishing the field measurements, he plays back the recordings while seated at a computer and types the values directly into a spreadsheet that will do the calculations.