A Dwarf Pear Tree: Another Genetic Engineering First
ARS News Service
Agricultural Research Service, USDA
Judy McBride, (301) 504-1628, firstname.lastname@example.org
July 2, 1999
The first genetically engineered dwarf pear tree of an existing variety has
been developed by Agricultural Research Service scientists. Dwarf trees are
more productive than traditional-size trees and offer growers other
advantages as well.
ARS horticulturists Ralph Scorza and Richard Bell at the Appalachian Fruit
Research Station in Kearnesyville, WV, dwarfed Bosc pear trees by inserting
a gene originally isolated from a bacterium. The new dwarf trees are growing
in greenhouses at the lab, and the scientists expect the trees to bear fruit
in about two or three years.
The bacterial gene can be used to dwarf rootstocks or to make the scion—the
top part of the tree—smaller or dwarf. According to Bell, the pear industry
relies on only a few major varieties and needs to improve them. Dwarfing
will do that.
In addition to being more productive, dwarf fruit trees allow high-density
plantings of smaller trees that can produce more fruit in the same area of
land than the larger, standard-size trees. And they're easier to manage,
prune, spray and harvest. Fruit from a dwarf tree is the same size as fruit
from a normal tree.
For those growers not interested in dwarf trees, Scorza and colleagues have
developed a peach tree with a new, columnar shape. Perfect for the home
gardener with limited space, the columnar tree has upright, narrow branches
that grow close to the tree trunk without shading other fruit or vegetables
that may be growing nearby.
Like dwarfs, the columnar trees require much less management and will allow
high-density growing. They eliminate the large space necessary between
traditional trees. Therefore, chemicals and fertilizer need be applied only
to a very small area, saving the grower money and reducing environmental
impacts. Compared to traditional size trees, at least three times as many
columnar trees can be grown per unit of land.
These new trees—which bear excellent quality fruit—are expected to be
available to home gardeners within the next few years.
ARS is USDA's chief scientific research agency. A more detailed story on
this research is available in the agency's July Agricultural Research
magazine, available on the Internet at:
Scientific contact: Ralph Scorza and Richard Bell, ARS Appalachian Fruit
Research Station, Kearneysville, W.Va.; fax (304) 728-2340; phone (304)
725-3451, Scorza Ext. 322, Bell Ext. 353, email@example.com,
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