DeJong, though outspoken about cutbacks in funding, also shared some good news during his talk about the HBOK series and dwarfing rootstock.
He is predicting that California’s tree fruit will size well “except for the early stuff,” thanks to a cooler, wet spring. “Crummy weather in the spring is the best you can have for good fruit size,” DeJong said. “We recall 2004 when there was a super hot spring, 80 degrees all of March during 30 days after bloom. There was terrible fruit size that year.”
DeJong said some of the HBOK series is being released under the term Controller, and that Controller 5 is particularly good as a backyard tree. But because its fruit is smaller, it’s not recommended for commercial planting.
His research has shown that growers can make up production on other lower sizing rootstocks by putting trees closer together. “They invest less in maintenance of trees and get closer to a pedestrian orchard,” he said.
With size controls, DeJong said, fruit tends to have higher sugar, and trees are more open.
Day showcased Owen T. plum trees that had been mechanically topped at 9 feet and then cut by hand to 8 feet.
Short trees managed correctly can produce as much as tall trees, he said, “because we thin off so much to get the larger sized fruit. “We don’t take anything near to the ultimate bearing potential.” He said. “We don’t need the huge structure.”
Day said fruit at the top of the tree consistently sizes better. “The top 3 feet is always the top 3 feet whether the tree is 8 or 14 feet tall.”
He said Nemaguard rootstock, a mainstay for the tree fruit industry, can be used to grow shorter trees by backing off the amount of nitrogen used.
Those who attended the field day included Joe Bezerra, executive director of the California State University Agricultural Research Initiative, and director of the California Agricultural Technology Institute at Fresno State University. He is also concerned about cutbacks in the CSU system.
Each system faces overall cutbacks from the state that could range between $500 million and $1 billion each, said Bezerra and Johnson. Both men talked of the need to try to form partnerships between industry players, government entities and educational institutions to meet the added challenge.
“There needs to be increased collaboration across system lines,” Bezerra said.