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Science Update
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Sunflowers.
(K5752-2)
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Protecting U.S. Sunflowers Against
Broomrape
So far, U.S. sunflower growers have not been plagued by broomrape. But just in
case this exotic weed should defy quarantine efforts and enter the country,
researchers are searching for sources of resistance that could provide
protection.
Broomrape, Orobanche cumana, is a parasitic plant with no capacity for
making chlorophyll on its own. So it steals nourishment from sunflower roots,
stunting or killing the plants. It now infests sunflower crops in China and
countries bordering the Mediterranean and Black Seas.
International researchers try to develop new sunflower lines with resistance
genes to keep up with the evolution of new broomrape races. But
ARS scientists working with colleagues
at the Instituto de Agricultura Sostenible in Córdoba, Spain, have taken
that defense a step further. They have found a way to use interspecific
hybridization—that is, crosses between cultivated sunflowers and distant
relatives that were difficult to impossible to make, until now. Some of these
improbable crosses have proved to be not just resistant—but immune—to
broomrape race F, the newest one.
This work was spurred by losses of 40 to 50 percent of Spanish sunflower crops
to broomrape races E and F in the early 1990s. Research collaboration has led
to seven new, resistant sunflower germplasms derived by crossing USDA lines
with race E-resistant ones from Russia, Romania, and Turkey. New conventional
hybrids from those lines now growing in Spain are suffering only 10- to
15-percent yield losses.
Chao C. Jan and
Jerry F. Miller, USDA-ARS
Red River Valley Agricultural Research
Center, Fargo, North Dakota; phone (701) 239-1319, (701)239-1321.
Blackeye Peas Go Green
Plant breeders recently released the first-ever blackeye-type southern pea that
shows the green cotyledon seed trait. Peas of the new variety retain their
fresh green color, even when harvested dry. Green Dixie Blackeye was released
for use by both home gardeners and the dry-pack bean industry. The peas can be
harvested fresh for immediate consumption or storage in home freezers, as well
as fully dry—for storage or sale as an attractive dry pack.
Green Dixie Blackeye is the result of 10 years of cross-breeding of the large,
cream-type Bettergreen variety with the popular and high-yielding Bettergro
Blackeye. It produces dry pods in around 70 days, each holding about 14 peas
that are larger than those of Bettergro Blackeye. And it outyielded the
top-producing Arkansas Blackeye #1.
Dry peas can be restored to fresh-harvest seed size and color by soaking in
water for 2 hours and blanching in boiling water for 3 minutes. Seed of Green
Dixie Blackeye has been offered to over 240 commercial seed growers and
food-processing companies, so an adequate seed supply should be available by
2002.
Richard L. Fery, USDA-ARS
U.S.
Vegetable Laboratory, Charleston, South Carolina; phone (843) 556-0840.
Can Copper Save the Day for Catfish Eggs?
Fish farmers routinely apply a chemical called copper sulfate to
catfish-rearing ponds to curb excessive growth of oxygen-hungry algae. Less
algal growth means healthier fish and lower production costs. Now researchers
are wondering if the compound might also cut down on waterborne fungi that
destroy catfish eggs before they can hatch into small fry.
Since the 1980s, fish farmers have had only one officially approved therapeutic
drug—formalin—available to protect their eggs. Copper sulfate would
be a less costly alternative that's also easier to apply and less smelly.
Cooperative research with Phelps Dodge Refining Corp., El Paso, Texas, will
attempt to find out if copper sulfate can protect channel catfish eggs without
harming young hatchlings. Approval is already being sought for its use in
treating a parasitic disease of fish called ichthyopthiriasis.
Billy R. Griffin, USDA-ARS
Harry K. Dupree Stuttgart National
Aquaculture Research Center, Stuttgart, Arkansas; phone (870) 673-4483.
Rice Is Nice—for Doughnut-making
Modified rice starch, rice flour, and other rice-based ingredients, when
incorporated into doughnut dough, reduce the absorption of frying oil by up to
70 percent. Mixed with wheat flour, the rice ingredients make a dough that is
more tender, consistent, and moist, and they reduce oil uptake. Though less
oily, the doughnuts made from the experimental formulations compare favorably
in taste, texture, and other sensory properties with traditional cake
doughnuts.
Researchers have tried many different combinations of wheat and rice
ingredients, searching for the best ratio for reducing oil absorption without
sacrificing consumer appeal. Tests of the finished doughnuts showed all-wheat
doughnuts to have 24 to 26 grams of oil, while some wheat-rice ones had as
little as 8 grams.
Frederick Shih, USDA-ARS
Food
Processing and Sensory Quality Research Unit, New Orleans, Louisiana; phone
(504) 286-4354. |
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"Science Update" was published in the
February 2001
issue of Agricultural Research magazine.
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