The cherry of the future

Matt Whiting shares lessons learned in developing the UFO training system for cherries during an orchard tour on December 5.

Tree fruit industry members recently received progress reports from scientists involved in a major research project that’s using a total systems approach to develop profitable and efficient systems for sweet cherries. The reports were followed by a tour of a commercial cherry orchard that’s putting the research concepts into practice.
The December 5 show-and-tell meeting was held in conjunction with statewide tree fruit presentations held in Yakima, Washington. A more in-depth review was held on December 6 for the research team to plan and coordinate activities as the project enters its fourth and final year.

The comprehensive project is partially funded by a $3.9 million grant from the Specialty Crop Research Initiative, a program of the U.S. Department of Agriculture. The research involves a multidisciplinary team of private companies and scientists from universities in Washington, Oregon, Michigan, and California. Washington State University horticulturist Dr. Matt Whiting and WSU engineer Dr. Qin Zhang are project leaders.

The research team’s long-term goal is to develop cherry orchard systems of the future, Whiting said. “This is a total systems approach to developing a sustainable, profitable, and efficient way to produce sweet cherries. It begins with genetics and breeding new varieties, includes new mechanical harvest and assist technologies, and ends with developing novel packaging to extend shelf life and new markets for stem-free cherries.”

Tree structure

As the lead horticulturist on the team, Whiting is working to develop cherry tree architecture for the future.

His vision of the orchard of the future involves a tree design he calls the Upright Fruiting Offshoots or UFO. This new tree training system can take advantage of semidwarfing and precocious rootstocks and grow a precision canopy that can be mechanically pruned, thinned, and even harvested. The contained canopy minimizes the environmental footprint through more targeted spray applications and could even allow over-the-row spray applicators.

“The current cherry tree system is a very complex structure, is expensive to grow, and difficult to prune,” said Whiting, speaking of traditional cherry trees grown on rootstocks like Mazzard that result in large canopies requiring ladders for picking.

He credited Yakima Valley orchardists Mark Hanrahan and Keith Oliver for trying the new UFO systems in commercial settings. Hanrahan showed several blocks planted to the UFO, the oldest in their seventh leaf. It’s been a learning process to develop optimum planting, training, and pruning techniques for the UFO system. Adjustments have been made as the research team and grower cooperators experiment with best practices.

Last winter, Whiting used a mechanical pruner with horizontal and vertical saw blades to prune a UFO test block at WSU’s research orchard. He sees opportunity to mechanically prune UFO training systems every second year, following up in the off year with hand pruning to reshape and clean up the scaffolds. Mechanical pruning would be a significant savings in labor for growers, as it requires only about 10 percent of the time needed for hand pruning, he said.

Cherries in blocks planted to the UFO have colored well, said Oliver, adding that they haven’t used any reflective material in the Olsen UFO orchards.

“Fruit color in the UFO system has been a nice surprise,” said Whiting, citing an Early Robin block that was harvested in a single pick last year because it colored so well.

“Fruit color in the UFO system has been a nice surprise,” said Whiting, citing an Early Robin block that was harvested in a single pick last year because it colored so well.

Cherries of the future

A team of WSU researchers is collaborating on developing cherry varieties for the future that are suited for mechanical harvest and fall easily from the tree. Fruit breeding efforts include identifying genes responsible for a variety of fruit traits, such as abscission, using consumer preference studies and sensory analysis to measure consumer acceptance, and traditional fruit breeding work.

Engineers have their part in the ambitious research project, searching for engineering solutions to improve labor efficiency. Scientists are developing handheld devices that can harvest and catch fruit. They are also working to improve a prototype mechanical cherry harvester developed earlier by the U.S. Department of Agriculture.

The comprehensive project also involves market development for stem-free cherries and development of novel packaging for stem-free cherries to improve shelf life. Scientists are testing a heat-sealed, small container made of biodegradable material, developed by Michigan State University. Studies have found that stem-free cherries can keep for up to four weeks without fungal growth in the small container because the package creates a modified atmosphere environment.

In a market study to measure retailer and consumer acceptance of stem-free cherries, Dr. Fran Pierce of Aginfomatics, LLC, shared that retailers surveyed are not concerned about selling stem-free cherries, as long as quality is there.

If the industry had to move tomorrow to stem-free cherries because of labor issues, Pierce says that retailers could sell the cherries in 2-pound bags and the new containers. “As long as quality remains high, retailers told us that stem-free cherries would sell.”