California Walnut Board Focuses On Research

California Walnut Board Focuses On Research

It’s no secret walnut growers, like most of their counterparts farming the 300-plus crops that flourish in California, have some large obstacles looming. Soaring land and production costs — coupled with the drought and increasing government regulations — are certainly daunting.


“We’ve got some major challenges ahead, that’s for sure,” says Jerry Moore, who farms walnuts in the southern San Joaquin Valley, just east of Visalia.

Moore, of all growers, should know. He serves as Chairman of the California Walnut Board’s Production Research Committee (PRC). The committee takes recommendations from the Production Research Advisory Council (PRAC), which was formed a decade ago.

PRAC is composed of eight members, including both growers and University of California Cooperative Extension (UCCE) farm advisors, who go over all the research possibilities. They then prioritize them, assigning a rating of 1 to 5, depending on importance.

PRC looks at those ratings and then makes the final decisions. The two groups work hand in hand, says Moore, though the PRC makes the calls on funding.
One change this year is for the first time in two decades, Dave Ramos won’t be directing the research. Moore says PRC will miss Ramos, who retired after 18 years.

That said, Moore says PRC is happy to have Joe Grant on board. After recently retiring after 30 years as a University of California (UC) Cooperative Extension Farm Advisor in San Joaquin County, Grant is taking over the half-time post as Research Director.

“We’re so happy to have Joe,” Moore says. “He will add a lot to what we’re doing in research.”

Grant is perhaps best known in research circles for his work on the biocontrol of codling moth. By instructing growers on the benefits of mating disruption, the industry was able to move away from its reliance on chemical controls. Grant’s efforts earned him and the Entomology Working Group within PRAC the IPM Innovator Award from the California Department of Pesticide Regulation in 2013.

Asked what areas of research were the priority of the PRC in the coming year, Moore listed genetic improvement – both in varieties and rootstocks – orchard management, tree nutrition, and insect control. Grant fleshed out these topics in more detail:

Genetic Improvement
In general, the California Walnut Board supports a mixture of short- and long-term efforts. Short-term efforts take the form of such things as cultural practices and crop protection sprays. Long-term efforts generally include breeding.

Some problems are difficult indeed to solve. Take Walnut Blight, which was first reported about 100 years ago in Southern California, where the industry was founded before moving to the San Joaquin Valley. Growers are still fighting that difficult disease, and mostly with one ingredient, copper.

But now the industry is advancing into walnut genome research. Now that the walnut genome has been mapped, it won’t be too long before researchers use faster breeding methods to develop walnut blight-resistant varieties.

The industry is doing a lot of research to find new disease-resistant rootstocks, such as the RX1 and VX211, two so-called clonal Paradox rootstocks. “We are rapidly getting to a place where we’re going to have more options for more and better characteristics,” he says.

One overriding goal is trying to find an early-harvest ‘Chandler.’ It’s by far the most popular variety in the state, accounting for well over half the production. If there were a variety similar to the late-harvesting ‘Chandler,’ growers could smooth out the harvesting and processing season.

Timing, as well as quality, is the reason for the success of ‘Ivanhoe,’ which was released by the walnut breeding program at UC-Davis headed up by Chuck Leslie a half-dozen years ago. Not only does ‘Ivanhoe’ produce the desirable light-colored kernels for which the popular ‘Chandler’ variety is known, but it is harvested a month before ‘Chandler.’

‘Ivanhoe’ works great for growers like Moore in the south, and lots of ‘Ivanhoe’ acres are being planted. But it leafs out too early for Northern California growers, who get more rain, earlier, and can get blight. Up north, growers are trying ‘Solano,’ which appears promising. But perhaps the most promising variety to come along recently is the just-released ‘Durham,’ which is still something of an unknown but looking good.