A researcher in Oregon who has been studying the viability of various table grape varieties believes there is good potential for industry growth in the state. 

The extension center's demonstration plot

The grape sector is primary focused on wine grapes, but a representative from Oregon State University's North Willamette Research and Extension Center says there is room for local table grape production to expand.

Faculty Research Assistant Amanda Vance, whose work focuses on berry crops, told Fresh Fruit Portal table grape plantings started at the farm in 2001.

A few years later an Arkansas table grape breeder brought over some of his selections for trials.

However, thorough scientific research had not begun on the varieties until much more recently.

"It had mostly been a demonstration plot, more for growers if they wanted to come and see some of these varieties," she said.

"So there wasn't really any hard scientific research going on until 2014 when we started this."

Her work has identified several varieties that might be suitable for commercial growing in the Willamette Valley, which lies around 20 miles south of Portland.

She said it was unlikely Oregon would become a major commercial grower of table grapes, but the varieties could be used by farmers looking to diversify their production.

"There are a number of growers, mostly small farmers, that are growing table grapes. But we feel like there’s potential for more people to be growing them and selling them at things like farmers' markets. There's at least one grower that I know of who sells to grocery stores. 

"We're probably not going to be competing on a high level with California on table grapes, but I think it can be another good addition to the local fruit market. 

"We also wanted to test these new varieties that came from the University of Arkansas to see how they stood up the some of the varieties that we know people are growing in this area."

Candice table grapes

Of the 41 cultivars on a one-third acre demonstration plot, including several selections from Cornell University, she selected 13 seedless varieties to study.

"The two that were the most promising of the ones that people are already growing that we felt performed really well were Candice and Neptune," she said.

Candice is a red grape variety from Cornell with good flavor, uniform clusters, and a small berry size. While Neptune is a green variety from Arkansas with high yields and a large berry size.

The best of the newer varieties from Arkansas is called A2932. It's a green grape and it will be named and propagated over the next year or so.

Vance is set to carry out a further study on the variety this year to see if yields can be increased by different pruning methods, and also assessing the postharvest characteristics. 

She said interest in table grapes came from a diverse mix of farmers. Many in the Willamette Valley grow vegetables, while blueberries and blackberries are among the most popular fruit crops, she explained.

"Our other research efforts in our berry program are obviously focused on those crops as they are a bigger market in our region," she said.

"But we think some of the growers may be interesting in adding table grapes, and some of the smaller vegetable growers who are doing really diverse operations could be interested in adding them to their mix also.

"The nice thing about grapes is they don’t require as much fertilizer or water as other crops. Here in Oregon the bigger market for grapes is wine grapes, but I think that table grapes could potentially grow into a larger market."

Vance's work is to be published in The Journal of the American Pomological Society, but she said the extension center also planed to provide the information to growers in a more accessible way, such as though publications, newsletter articles and a grower workshop due to take place this fall.

Photos: Courtesy of the North Willamette Research and Extension Center

www.freshfruitportal.com