Issue link: http://read.dmtmag.com/i/31248
Why innovate? The annual sweet cherry harvest is one of the most labor-intensive of all agricul- tural endeavors. Harvest costs for sweet cherries are highest among tree fruits, accounting for approximately 60 percent of the cost of production, largely due to the amount of fruit per tree, large unwieldy tree architectures, and the lack of mechanical harvest options. The gen- eral harvest process for sweet cherry fruit has not evolved in over a century—labor- ers carry and place their ladder in the tree, climb to access fruit, pick the fruit at its stem (pedicel), place the fruit into a bag secured over their shoulders with straps, then climb down and dump the fruit into either a lug or bin. It is estimated that sweet cherry harvest requires approxi- mately two-to-threefold more labor hours per unit of land than other temperate tree fruit for reasons listed above. In the Pacific Northwest, the cherry industry faces imminent labor shortages due to a variety of factors, including immigration reform, increased demand for harvest labor, and competition for laborers from other industries. This insufficient supply of har- vest labor has significant and potentially ruinous consequences for the sweet cherry industry. If new harvest technologies can be developed, worker safety will also improve. The perils of ladder-intensive harvest are well documented and under- score the desperate need for innovative harvest technologies. The adoption of a mechanical and/or mechanical-assist harvest system for sweet cherries has the potential to revolutionize the sweet cherry industry. Tests have shown that the USDA-ARS prototype harvester dramati- cally reduces labor without negative effects on fruit quality, but produces a stem-free cherry product. Preliminary market research has shown consumer acceptance of stem-free cherries. However, the potential for stem-free cherries has not been realized for lack of an integrated system from field to table. The hope is within the four years of this research project, an integrated produc- tion, processing, and marketing system will be available for industry to adopt. Progress/research findings Objective 1: Develop a high efficiency, productive, angled fruit wall orchard system. In 2010, four new orchards were planted (2 in Oregon, 2 in Washington) as research/demonstration sites for the angled UFO (Upright Fruiting Offshoot) architecture. Another UFO orchard was planted with a collaborator in Tasmania, Australia, to provide a site for counter- seasonal research. Two additional orchards are set to be planted in Washing- ton and Oregon this spring. A “how to” video is also in the works and should be available in June 2011. Objective 2: Establish the genetic basis for sweet cherry abscission. Sweet cherry cultivars and breeding populations were phenotyped for pedicel retention force and fruit traits including www.goodfruit.com GOOD FRUIT GROWER MAY 15, 2011 17 weight, size, stem length, firmness, acidity and sweetness in 2009 and 2010. Signifi- cant differences in pedicel retention force were observed among cultivars and between years as well as between culti- vars and years. This significant genotypic variation for pedicel retention force sug- gests that it will be relatively easy to breed for low pedicel retention force. Work was also done to test the estab- lished model of abscission in sweet cherry. In year one, cherry genes homolo- gous to abscission-related genes from other species were identified, and sam- ples were collected to identify genetic net- works associated with pedicel-fruit abscission in sweet cherry. Objective 3: Improve labor efficiency and safety by developing mechanical and/or mechanical-assist harvest technologies. The USDA mechanical harvester and the shake-and-catch mechanical-assist harvester were both field tested for effi- ciency and impact on harvest efficiency and fruit quality. Field demonstrations of