Issue link: https://read.dmtmag.com/i/657340
12 APRIL 1, 2016 Good Fruit Grower www.goodfruit.com T he arsenal of information growers can bring to bear on the question of which rootstock to use has grown again. Recently published research by a team of U.S. Department of Agriculture and Cornell University scientists says growers should match rootstocks' varying abilities to absorb minerals to the minerals available where they are to be planted. The research points to a day when growers may be able to adjust fertilization programs according to what rootstock forages well on its own versus one that doesn't. "Rootstocks differ in their ability to forage for minerals, and this affects fruit quality," said Dr. Gennaro Fazio, the lead researcher and a plant breeder and research geneticist with the USDA Agricultural Research Service's Plant Genetic Resources Unit in Geneva, New York. The impact of this work could well be felt all along the fruit production and marketing chain. "Some packers measure the concentration of several nutrients in lots of apples to estimate storage ability and storage disorders already," Fazio said. Others are giving the idea a long look. "It's something we are considering for use in the future," Lee Showalter, grower services and food safety manager at Rice Fruit Co. of Gardner, Pennsylvania, told Good Fruit Grower. Growers might find ways to reduce input costs: If one rootstock is more efficient at potassium or phosphorus uptake, Fazio said, they may not have to apply as much of either. The knowledge can also be used to reduce the occurrence of fruit defects. "We know that too little cal- cium, too much potassium and too much magnesium can bring on bitter pit," he said. "Knowing how well root- stock absorbs and transports these minerals can drive the decision of which scions to graft." Some rootstocks pass along fairly equal nutrients to scions, while others may be very good at passing along particular minerals, such as calcium. Fazio's earlier research showed some Geneva root- stocks are up to 25 percent better at sending potassium up the chain. They also detected three chromosomes having an effect on calcium delivery and another for sodium. But what happens after the graft needs more research. "We don't have the knowledge of how proficient scions are at moving certain nutrients," he said. For now, however, Fazio and his team have tracked Know your soil before picking your RooTsTocK Nutrient Management Researchers encourage growers to match a rootstock's ability to absorb nutrients to those nutrients found in the soil. by Dave Weinstock Gennaro Fazio "Rootstocks differ in their ability to forage for minerals, and this affects fruit quality." TECH-FLO ® ZETA ZINC 22 ASK YOUR P.C.A. OR CALL NUTRIENT TECHNOLOGIES TOLL-FREE: 877/832-4356 FOR THE DEALER NEAREST YOU. Just because you put a foliar zinc on doesn't mean the job's done. Some zinc products are so ineffective they are better suited as sun- screens or paint. In trial after trial, TECH- FLO ® ZETA ZINC 22 (22% Zinc) has been shown to be the most effective foliar zinc product on the market today, getting the zinc into the tree where it is needed. For the best value for your nutritional dollar, choose TECH-FLO ® ZETA ZINC 22. UNSURPASSED FOLIAR ZINC PERFORMANCE! …PUTTING ZINC ON PUTTING ZINC IN… PUTTING ZINC IN…