North American Fruit Explorers mailing list at ibiblio

["Lon J. Rombough" <lonrom@hevanet.com>]

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From: ARS News Service <NewsService@ars.usda.gov>
Reply-To: ARS News Service <NewsService@ars.usda.gov>
Date: Tue, 04 Nov 2003 09:46:15 -0500
To: ARS News subscriber <lonrom@hevanet.com>
Subject: Dwarf Apple Trees, Sooner

STORY LEAD:
A Shortened Wait To Discover if Apple Tree's a Dwarf

___________________________________________

ARS News Service
Agricultural Research Service, USDA
Luis Pons, (301) 504-1628, lpons@ars.usda.gov
November 4, 2003
___________________________________________

Agricultural Research Service scientists may have significantly reduced
the time it takes to tell if an apple tree will grow to be a dwarf and
resist diseases. Through gene mapping, plant geneticist Genarro Fazio
and plant biologist H. Todd Holleran of the ARS Plant Genetic Resources
Unit in Geneva, N.Y., have discovered the genetic inheritance of the
dwarfing characteristic in apple tree roots, also known as rootstocks.

The discovery can help researchers find molecular markers that can help
identify dwarf varieties, as well as positive and negative traits within
those varieties, early in their development. Currently, a tree must grow
for about 12 years before growers can tell whether it's a dwarf. In all,
the entire process of evaluating rootstocks for tree size and disease
resistance takes about 30 years per tree.

According to Fazio, the ability to read genetic markers may cut these
evaluation times in half. In addition, further understanding of the
workings of the genetic inheritance gene may make it possible to
transfer the knowledge to other tree fruit systems. Fazio is director of
the Geneva lab's apple rootstock breeding project.

Dwarf varieties of apple trees have become popular among growers during
the past 25 years. While normal-sized trees commonly grow to a height of
20 to 30 feet, dwarf varieties grow only 10 to 12 feet tall. Their yield
and fruit size are the same as from full-sized trees, but growers can
plant about seven times as many trees per acre. Dwarfs are also easier
to spray for bugs and to prune and harvest.

In all, apples are a $1.5 billion-a-year industry. They are grown
commercially in 35 states.

You can read more about this research in the November issue of
Agricultural Research magazine, available online at:
http://www.ars.usda.gov/is/AR/archive/nov03/apple1103.htm

ARS is the U.S. Department of Agriculture's primary scientific research
agency.
___________________________________________

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