Representatives of a challenged California raisin industry are among those who are helping researchers wean out some cultivars to focus on those which are most prized.
“We are hoping to get industry/grower comment on accessions (cultivars) we should move forward with and pursue and which should be rouged from the field,” said Craig Ledbetter, resident geneticist with the U.S. Department of Agriculture’s San Joaquin Valley Agricultural Sciences Center in Parlier.
The “raisin showing” was the first such event involving industry members in some 30 years, Ledbetter said. By contrast, he said as many as three table grape showings are held each growing season to help decide what should be released and what should be removed from research programs.
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Raisin showing participants, who included college students and some members of the center’s administrative staff, rated more than 45 unnamed cultivars on appearance, flavor, and mouthfeel. They also sampled some industry staples, including Thompson seedless, Fiesta, DOVine, and Selma Pete.
“This is a good way to brainstorm with farmers and packers alike,” said Robert Sahatjian, farm manager and grower relations representative with Victor Packing in Madera.
Sahatjian said fruit quality is a key criterion in choosing what to plant or pack.
He said no price has yet been set for this year’s crop and that growers and packers have entered into a conciliation process. While a field price is commonly set by the end of October, Sahatjian said he does not expect to see that happen “until after the new year.”
“We’re in major over-supply due to the uncertainty,” he said, adding the industry faces stiff competition from raisin-growing regions including Turkey, Iran, Chile, and South Africa.
Steve Spate, grower representative for the Raisin Bargaining Association, said the industry has been greatly affected by a decline in the demand for green grapes for concentrate. It has dropped to some 80,000 tons per year, compared to past years when it was as much as 400,000 tons.
Raisin grape acreage has been declining in recent years, dropping to 184,000 in 2015. Spate said many growers are turning to other crops including tree nuts and citrus. He said some growers had bulldozers at work in their vineyards soon after harvesting this year’s crop.
Industry leaders also note that new labor laws – including a $15 per hour minimum wage and overtime based on an eight–hour day and 40-hour week – are helping drive traditional raisin grape acreage out of production. Less than half of grapes for raisins are harvested mechanically.
While this year’s crop is expected to be smaller than last year’s, Spate said fruit quality may be higher. The Raisin Administrative Committee has estimated a crop of 270,000 tons, “plus or minus 15,000,” Spate said.
Rachel Naegele, research horticulturist at the Parlier center, explained that all varieties being considered are natural dried-on-the-vine cultivars. She said the center is no longer focusing on vines which require cane cutting.
The cultivars out for tasting and viewing included some with a red flesh, some resistant to powdery mildew, some resistant to Pierce’s Disease, and some resistant to both.
Some of the raisins set out for tasting were quite small, a trait that Ledbetter said is not generally favored. He said attention is being focused on achieving a raisin mass between 7 and 15 grams, “mid-sized raisins.”
As he tasted raisins chosen for their resistance to disease and mildew infestation, Sun-Maid field representative Mike Moriyama said they could be a boon to organic growers. While the percentage of raisins organically grown remains small, he said they command a premium, and disease and insect pressures continue to challenge organic growers.
A new dried-on-the-vine variety called Sunpreme was also available for sampling. Among participants in the raisin showing was Matthew McMillan, a sales representative with Vintage Nurseries and Mercier California, two of only five licensed nurseries where Sunpreme is being propagated.
McMillan does not expect the first commercial plantings of Sunpreme to occur before 2018.
The USDA has been involved in grape breeding for nearly a century. For raisin grapes, one goal has been to move harvest times earlier to hedge against a threat of rain.
Ledbetter explained that researchers in the field evaluate raisin quality characteristics that include crop load and cluster size, spur versus cane fruitfulness, berry attachment and raisin drop, and dates of wilting and complete raisining.
In the lab, they look at other objective data including raisin color and mass. And they also look at subjective criteria that include wrinkling, flavor, skin, seed trace detectability, meatiness, uniformity, attractiveness, and stem attachment.
Ledbetter said consumers consistently prefer a mouth feel of raisins with a fine wrinkle texture to ones that are coarse.
Before tasting began, Ledbetter told participants he and others were interested in comments “whether good or bad.”