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Hops plantlets can be stored in semipermeable
plastic bags for 1 to 3 years without transfer but must be evaluated three
times a year for viability. Technician Jeanine DeNoma (left) and plant
physiologist Barbara Reed inspect plants stored with standard MS iron, which
allows for longer storage than media with sequestrine iron. Click the image
for more information about it.
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Ironing Out Storage Kinks for Hops
By Laura
McGinnis
January 17, 2008 To help breeders improve hops for
brewing and other U.S. industries, the Agricultural Research Service (ARS) National Clonal Germplasm Repository
(NCGR)
maintains a diverse hop collection at Corvallis, Ore. There, scientists and
curators maintain germplasmgenetic material such as plants, shoot tips
and seedsfrom more than 150 hop varieties collected from over 24
countries, from the Yugoslavian Ahil to the Czech Zlatan.
They cultivate about 250 accessions as potted plants and preserve 57
accessions as tissue cultures. Thirty accessions are also
cryopreservedstored frozen in liquid nitrogen for extended
periodsat the
National
Center for Genetic Resources Preservation in Fort Collins, Colo. The tissue
cultures can be stored at about 39 degrees Fahrenheit for two years or longer.
Plant physiologist
Barbara
Reed and NCGR colleagues investigated how 12 hops genotypes responded to
the iron formulation used in the culture medium during storage. Their
observations have led to improved storage techniques.
Just as an adult recovering from surgery and a teenager preparing for a
marathon will have different dietary needs, the nutrient requirements of plants
vary according to their developmental stage and storage environment.
Identifying the precise requirements is essential to successful germplasm
storage.
In the past, NCGR scientists noticed that hop cultures stored on a standard
medium containing a moderate level of iron sometimes emerged iron-deficient
when grown out later. They learned that adding sequestrene iron to the growth
medium enabled most cultured plants to grow better.
But Reed and her colleagues also observed something paradoxical about the
iron-rich media. Although most hops cultivars grew better in an iron-rich
culture, the scientists found that they stored better in an environment with
less iron.
The researchers have since modified their storage procedure accordingly,
reducing the iron content of the plants' media about a month before storage.
This reduces iron deficiency without compromising the accessions storage
life.
Read
more about this research in the January 2008 issue of Agricultural
Research magazine.
ARS is the U.S. Department of
Agriculture's chief in-house scientific research agency.