Issue link: https://read.dmtmag.com/i/298602
www.goodfruit.com GOOD FRUIT GROWER MAY 1, 2014 13 Given the fact that trees are only in leaf part of the year, and that trees start small and need to grow to fill space, that is not surprising. The desire to intercept a higher percentage of avail- able light and avoid the effects of shading led to the grad- ual adoption of systems with taller trees, narrower alleys, and thinner, hedgerow-like rows. The desire to harvest more fruit required that trees put more of their effort into mak- ing fruit and less into making wood. Today, about 70 percent of the available carbohy- drates are partitioned toward fruit, much more than it used to be, and the major reason is dwarfing rootstocks, he said. As Palmer sees it, there are three keys to achieve good yields of salable fruit. • Carbon acquisition—the process by which trees take up carbon dioxide from the atmosphere through photosynthesis and store the sun's energy in the form of carbohydrates. • Partitioning—the process in which the tree "decides" whether it will make roots, shoots, leaves, wood, or fruit. • Fruit quality—making fruit people will buy. Major changes Palmer lists seven major developments that occurred during the last 40 years. • Realization of the importance of light interception and distribution, and their relationship to yield and quality • The widespread adoption and planting on dwarfing rootstocks • The understanding of an orchard as a system • The general move away from prun- ing toward branch manipulation as a tree training tool • The use of computer models to aid decision making • The use of plant growth regulators in the nursery and in the orchard—PGRs to produce high quality feathered trees in the nurseries and Apogee to control shoot growth in orchards • The application of physiological understanding to new cultivars, some of which are challenging to grow Palmer believes there are many challenges ahead for fruit researchers. A good, mature orchard—with good pruning and leaves operating at full effi- ciency—will gather 70 percent of the potential light energy from light, but it takes time to reach full production and biennial bearing reduces fruit production potential. Other things need work "Although eye appeal remains import- ant in many fruit, particularly color and freedom from blemish, taste is becoming increasingly important," he said. "Ini- tial purchase is based on eye appeal, but repeat purchase is based on eating experi- ence. Our production target should there- fore be yield, fruit size, appearance, and eating quality—maturity and dry matter concentration. You can ruin a market by giving consumers fruit that looks good but doesn't taste good." His prescription for grower success? • Make every bud count. Every leaf needs to function, every fruit be salable. • Improve rootstocks in apples and bring dwarfing rootstocks to pears. • Grow fruit to product specification, with greater emphasis on eating quality and less on cosmetic appearance. • Develop more multidisciplinary research teams that include molecular biologists. In addition, he said, three new factors are making their influence felt: sustainability, carbon footprint, and water footprint. "Our fruit-growing industries need to continue to pro- duce desirable, healthy, salable fruit, produced in sus- tainable, reliable, and predictable ways," he said. "Only by understanding the way in which the tree dynamically responds to its environment and its own internal regulation can we achieve these goals." • For more information about Palmer's research, see "Capturing the light," Good Fruit Grower, November 2010. When it comes to protecting your orchard, Delegate ® egate offers proven WG insecticide stands alone. Dele , , th, leafrollers, performance against codling moth — along with other tough pests like Oriental fruit mot spotted wing drosophila, plum curculio and apple maggot. What sets it apart? A mode of action so unique, it's the only one in its class. That makes Delegate key to any spray rotation program for pome and stone fruit, cranberries, blueberries or grapes. www.DelegateInsecticide.com 800-258-3033 UNIQUE CHEMISTRY FOR STANDOUT PERFORMANCE. ® Trademark of The Dow Chemical Company ("Dow") or an affiliated company of Dow Always read and follow label directions. ©2013 Dow AgroSciences LLC L38-359-010 (01/13) BR 010-34175 DAAGDELE2059 "Use the light you have to your best advantage. It's free and it drives your production." —Dr. John Palmer