Issue link: http://read.dmtmag.com/i/657340
14 APRIL 1, 2016 Good Fruit Grower www.goodfruit.com down a number of positive correlations between various minerals in certain apple rootstocks in New York soils. Differing soil types notwithstanding, the study's findings can be used in other fruit growing regions of the country, such as the Pacific Northwest, Fazio said, because rootstocks' genetic material remains unchanged no matter where it is planted. The same is true for rootstocks' nutrient absorption and transport mechanisms. Trial and results Fazio and his team took plant material — leaves and fruit — from mature apple rootstock with Honeycrip, Fuji and Enterprise scions in New York's Champlain Valley, Hudson Valley and Lake Ontario apple growing regions, as well as Cornell University's Lake Geneva Experiment Station. They oven-dried leaf and tissue samples, then ground them up and analyzed them for nutrient levels and carbon and nitrogen concentrations. In addition, they collected soil samples from the Champlain and Hudson Valley sites and analyzed them for soil nutrients. Soil analysis of the Hudson Valley sample showed optimal levels of phosphorus and potassium and very high levels of calcium and magnesium. After evaluating the sites' soil pH, they determined nutrient availability varied significantly. They also found some interesting relationships between nutrient levels in leaves and fruit. For example, despite finding similar zinc and copper levels in fruit taken from both sites, the amount found in leaves was quite different, which may mean the flow of zinc into fruit is tightly controlled, according to the researchers. Leaf calcium was similar in both valleys, but fruit calcium was not, leading them to believe calcium uptake is a variety-specific process. The same may be true for boron, phosphorus and sodium uptake. Initial site analysis showed significant differences in planting mineral content. Boron, copper, iron, potas- sium, sodium and phosphorous in the Champlain planting were significantly lower than in the Hudson Valley. However, fruit concentrations of magnesium, manganese, sulfur and zinc were significantly higher in the Champlain Valley. Higher calcium in Champlain Valley soils coupled with low calcium in Honeycrisp apples on the rootstocks evaluated might mean the variety is a poor calcium transporter. Other possibilities the researchers considered included a belief that high Champlain Valley soil pH could explain lower iron in the rootstock. Soil magne- sium and manganese were less available in the Hudson Valley, which might explain their reduced presence in the fruit of the region. The research also revealed that some rootstock in the Champlain Valley delivered far more calcium to Honey- crisp scions than others. Top performers were CG.6976 (Cornell rootstocks are classified with the prefix CG for Cornell Geneva before commercial release), CG.4002, CG.4814, Geneva 16, G.214 and Malling 7. By contrast, M.9 performed rather poorly in this function. In the Hudson Valley Fuji planting, G.214, CG.2406, G.969, Japan Morioka 4 and CG.5757 delivered the highest fruit calcium. Where fruit calcium was high, so too were iron, copper, zinc and manganese. Boron and phosphorous values correlated in this planting. The researchers observed something new as well: a strong correlation between sulfur and nitrogen values. New tools Fazio and his team have proven the wisdom of consid- ering rootstocks' abilities to absorb and transport miner- als from the soil to the graft. They did this by attempting to trace and identify mineral uptake and transport mech- anisms from root to fruit. Along the way, they identified a number of rootstocks that might represent initial steps toward improving Hon- eycrisp's ability to do well in storage. What's missing, and the next logical step in this research's progression, is an examination of mineral uptake and transport in the scion, from the graft forward to just short of the leaves and fruit. • The research team R esearch team members include Drs. Gennaro Fazio of the USDA Agricultural Research Service's Plant Genetic Resources Unit; Lailiang Cheng of Cornell University; Michael A. Grusak of USDA-ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; and Terence L. Robinson of Cornell's Geneva Experiment Station. R10 ROTATOR ® & MINI REG. DRAIN CHECK FIND YOUR CROP SPECIFIC WATER APPLICATION SOLUTION. Nelson Irrigation offers a complete line of products for a variety of applications — finding the right one is easy. 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