Skinny Peach Trees
These sweet, plump peaches grew
on columnar, or pillar, peach
trees (background), which stay
about 5 feet in diameter when
|Imagine plucking sweet, juicy peaches
from a tree that fits neatly in a tiny townhouse yard. That'll be a real
possibility in a few years, when the progeny from Ralph Scorza's new peach
trees go on sale at your local nursery. These unique, space-saving forms could
have an important impact on the ornamental and home garden market, says Scorza,
a horticulturist at ARS' Appalachian
Fruit Research Station in Kearneysville, West Virginia.
Commercial peach growers should reap even more benefit from his
columnaror pillarpeach that maintains a diameter of
about 5 feet, fully grown. The trees can be planted much closer together than
conventional trees, which branch out to 16 feet across. That translates into
many more peaches per acre, while land and production costs remain about the
same. According to one estimate, grower profits could increase by 20 to 50
"Many growers have hit the wall on maximizing peach production with
conventional trees," says Wanda Heuser Gale, an executive with
International Plant Management in Lawrence, Michigan. "They can't get
production high enough to make it profitable. That's why we're so excited about
this new peach."
Another advantage of high-density planting: growers may get a profitable crop
the second year after planting, when the pickings would be too slim in a
conventional orchard to make harvesting worthwhile, says Scorza.
Horticulturist Ralph Scorza
inspects a peach on one of
his newly developed columnar
| For growers who may not be ready for
such a radical change, Scorza also bred an upright tree that
reaches 8 to 10 feet across. "We wanted to release two different forms to
give growers a choice," he says, noting that the cash outlay to buy so
many columnar trees may be a stretch for some growers. Left unpruned, both new
trees reach a height of 12 to 15 feet after several years.
Both columnar and upright forms are undergoing field evaluations at the West
Virginia station and in 11 other statesfrom New York to Texas to
Washingtonplus 3 foreign countries. Greg Reighard, a professor of
horticulture at Clemson University in South Carolina, is in his third year of
evaluating pruning and training systems aimed at producing a wall
of fruit to increase efficiency.
"It's their form and rapid growth that make these trees unique. We want to
take these two traits and find a system that will maximize fruit production and
minimize cost," says Reighard. "They grow very quickly here in South
Carolina, so you're able to harvest a year earlier." His second-year
harvest produced between 12 and 25 pounds per tree from both tree forms.
Because their forms are so different, ARS has filed a patent application on
both. Scorza plans to involve commercial interests that will assess training
methods from the growers' standpoint and instruct nurseries on how to grow and
market the trees.
Parents Make the Difference
Scorza says high-density orchards have revolutionized apple production
worldwide. In the United States, per-acre apple production is about twice that
of peaches. Unlike apples, however, there are no suitable rootstocks for
dwarfing peach trees. So he looked for alternative solutions.
Around 12 years ago, while looking through the collection of a U.S. breeder,
Scorza located a Japanese ornamental peach tree having a columnar shape but
fruit too small to sink your teeth into. Later he found additional columnar
tree germplasm. Through conventional breeding with commercial cultivars, Scorza
produced both the columnar and upright tree forms and coaxed both forms to
produce higher quality fruits that flesh out to 2.75 inches in diameter. Plus
they are more productive than the parents.
The columnar form has two copies of the gene that sends the branches skyward,
Scorza says, while the upright has only one copy. But both selections produce
yellow-fleshed, dessert-type peaches with smooth, melting flesh that is sweet
and aromatic. They are firm fleshed, store well, and soften when completely
McBride, Agricultural Research Service Information Staff.
This research is part of Plant, Microbial, and Insect Genetic Resources,
Genomics, and Genetic Improvement, an ARS National Program (#301) described on
the World Wide Web at http://www.nps.ars.usda.gov.
Ralph Scorza is at the USDA-ARS
Appalachian Fruit Research Station,
45 Wiltshire Rd., Kearneysville, WV 25430; phone (304) 725-3451, ext.
322, fax (304) 728-2340.
"Skinny Peach Trees" was published in the
issue of Agricultural Research magazine.