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MSU Part of Award-Winning, Multi-State ‘Tree Fruit’ Project


Michigan State University, along with its 37 partner institutions across North America, received the national 2015 Experiment Station Section Excellence in Multi-state Research Award for a project to improve the sustainability of tree fruits.

Considered a hallmark research achievement within the land-grant university system, the award is given to multi-state research endeavors that have shown significant added value, degree of institutional participation, extent of multidisciplinary activity, number of integrated activities and evidence of additional leveraged funding.

Granted by the leadership of the Agricultural Experiment Stations (at MSU, AgBioResearch) with funding from the U.S. Department of Agriculture’s National Institute of Food and Agriculture (NIFA), the award requires collaboration between two or more states to address a shared priority that could not otherwise be addressed. The project will receive $15,000 in additional funds in recognition of the award, and a permanent plaque will be displayed at NIFA in Washington, DC.

At the Core of the Research

The award-winning project, titled “NC-140, Improving Economic and Environmental Sustainability in Tree Fruit Production Through Changes in Rootstock Use,” has been running continuously since 1967. Its primary focus has been to evaluate various types of dwarf rootstocks – such as apple trees – under a variety of growing conditions through the collaborative efforts of researchers and Extension specialists throughout the North America.

Researchers from several disciplines—including soil science, plant physiology, horticulture, plant breeding, entomology, plant pathology, statistics and agricultural economics—collaborate on NC-140. Their participation ranges from molecular approaches to rootstock breeding programs, and enhancing the efficiency of development and selection of the next rootstock generations, to water use evaluations and studies of cold hardiness, fruit size and bloom delay.

MSU’s original administrative adviser of NC-140 horticulturist Ron Perry began working on the project in 1980 as the MSU representative on a technical level. He held that position until 2001, when he was named chairperson of the MSU Department of Horticulture. Fellow MSU horticulturist Gregory Lang was then appointed to fill that role and continues as the MSU member on NC-140 today.

Producing extensive data on topics from disease susceptibility to fruit storage, the project has equipped growers with confidence to make the leap from conventional orchards to high-density plantings. Many orchardists began to gain the confidence to switch to high-density plantings in the late 1990s when data from the project showed the ability to transition from 200 trees per acre to 700 trees per acre, and to speed up profitability from 12 years to eight years.

As a result, apple orchards around the country have been undergoing a quiet yet monumental transformation. Large-canopy trees with knotty trunks and branches strong enough to climb are being replaced by small trees grafted onto dwarfing rootstocks. The trees, a fraction of the size of their predecessors, grow along trellises and produce more fruit on less land than the trees of yore. Plus, they are more sustainable and easier to harvest than the trees in previous systems.

This type of compact growing system is becoming the new norm. Dwarfing rootstocks now account for 85 percent of all apple tree sales, compared with 25 percent in 1995.

Productivity Boom

One of the most impressive advantages of the project has been increased productivity of the rootstocks. While U.S. apple acreage has shrunk by half since 1982, yields have conversely increased—from 19,000 pounds per acre in 1982 to 26,000 pounds per acre today.

Uniform, multilocation trials have exposed new rootstocks to a wide range of biotic and abiotic stresses. New protocols have been adopted to screen for susceptibility to fireblight, a major bacterial disease of apple. Other studies have revealed data on cold tolerance, soil health, plant pathogens and replant disease.

Testing a number of rootstock clones greatly reduced confusion within the industry, which was once dominated by one clone. It also identified replacements for clones with high mortality at many locations. In some trials, certain cultivar/rootstock combinations broke at the bud union, which led to enhanced support recommendations to reduce tree breakage. This project has also shown that rootstock selection by region has minimal impact.

Prior to NC-140, researchers, Extension specialists and growers had to develop their own independent rootstock trials, which could take up to 50 years to complete. Through NC-140, researchers are able to establish uniform rootstock trials on multiple sites around North America, reducing the time to 10 years. Sharing with breeders the summaries of performance and limitations by variations in soils and climate has sped up the process immensely by leveraging resources across institutions and eliminating duplicative efforts.

Harvesting is another area that has benefited. In 1965, the average U.S. apple planting was on large semi-dwarfing rootstocks, with trees about 18 feet apart and 29 feet between rows. Workers needed to use ladders and even shimmy up tree trunks to pick the apples. Now growers are planting dwarfing rootstocks spaced 21 inches apart in rows 13 feet apart, the result is a much more compact and more efficient space for harvesting and maintenance. Workers ride on platforms between the rows to pick the fruit.

The trees on dwarf rootstock also begin to bear fruit more quickly than conventional apple trees—in about two to three years, on average, compared with five or six years beforehand.

NC-140 maintains a website at root2fruit.org. More about NC-140 at http://www.nc140.org/.

– Holly Whetstone via AgBioResearch, Futures, Fall-Winter 2015 (click for full story)

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