College Station, Texas
July 28, 2009
The cowpea or black-eyed pea, as
it is more commonly known, is a New Year’s tradition for good
luck. But disease and particularly aphids, which can wreck a
crop within a few a days, are especially bad luck for the
cowpea, according to scientists. Several new lines of cowpeas
with genes that are aphid-resistant and less susceptible to
disease are currently being tested by researchers with
Texas AgriLife
Research and other Texas A&M System entities.
“The cowpea has been an important and popular food crop
throughout the southern U.S.,” said Dr. B.B. Singh, a visiting
professor in the soil and crop sciences department at Texas A&M.
“It’s commonly known as the southern pea, field pea, crowder
pea, black-eyed pea, purple-hull pea and pinkeye pea widely
grown in the southern states.”
The researchers’ discoveries could yield big rewards. An
international food crop, the cowpea was most popular in the
southern U.S. from the 1930s through ‘70s, and East Texas
remains a large U.S. cowpea-producing region.
And during times of drought, the cowpea can be a viable
alternative forage crop for livestock producers, due to its
ability to fix nitrogen, tolerate drought and provide
high-quality fodder, Singh said. It is a high-quality forage for
cattle producers, with a protein content as high as 28 percent
in seeds and 17 percent to 20 percent in the fodder after
harvesting the seeds.
However, the aphid is currently the biggest threat to cowpea
producers, Singh said.
“(Aphids) like dry weather,” explained Singh, who has spent his
entire career studying the cowpea. “Immediately after
infestation, they start sucking the juice (sap) from cowpea
leaves, stem, flowers and pods of the plants reducing their
growth and development and causing severe reduction in yield.
They also spread viruses. Aphids can ruin a crop within a few
days.”
Singh, came to the department as a visiting professor following
his retirement two years ago from the International Institute of
Tropical Agriculture, considered the epicenter of cowpea
research.
At Texas A&M, Singh is working with colleagues Dr. J. Creighton
Miller, D.C. Sheuring and Dr. Bill Payne using field trials in
College Station to find a solution to the aphid problem.
Singh has brought more than 35 lines of cowpeas with drought and
aphid tolerance, as well as resistance to other diseases and
higher yield potential, to College Station. His work there has
involved using conventional breeding methods to cross those
lines with six Texas and California varieties in greenhouse and
field settings.
“Many of the IITA lines are resistant to aphid, bacterial
blight, powdery mildew and drought, whereas most of the U.S.
lines are susceptible,” Singh said. “A number of crosses were
made to transfer the resistance to aphids and drought from the
IITA lines to the U.S. lines.”
In mid July, an aphid infestation hit the College Station
trials, putting the new varieties to the test.
“It’s been fairly severe, permitting selection of resistant
plants from the F2 and F3 populations,” he said. “Due to drought
and aphids this crop season, all of the susceptible cowpea
varieties and segregating plants have been completely damaged,
showing 80 percent to 100 percent yield loss, while the aphid
resistant varieties and segregating plants are completely
healthy with normal yield. The resistance is simply inherited,
very effective and highly stable across environments.”
From the segregating populations, the resistant plants with
diverse maturity dates, plant type, growth habits and seed types
have been selected to meet the need for grain type, fodder-type
and pasture-type cowpea varieties, he said.
“These are being advanced to achieve uniformity and
multi-location testing for stability of resistance and yield
potential," Singh added. The new aphid-resistant, high-yielding
varieties could be available to farmers as early as 2011, Singh
said.
"The cowpea has worldwide importance as a crop for both human
and animal nutrition," said Payne of Texas AgriLife Research,
assistant director for research at the Norman Borlaug Institute
for International Agriculture. "Introducing improved disease-
and drought-resistant and higher-yield varieties could not only
have tremendous potential for Texas and U.S. agriculture, it
could help provide poor and developing countries with an
important alternative source of nutrition."
According to the International Institute of Tropical Agriculture
in Africa, the cowpea is an important food crop in many African,
Asian and South American countries, especially as an alternative
source of protein where people cannot afford meat and fish. The
crop typically is grown by subsistence farmers with limited
agricultural resources, who use it to feed livestock or sell for
additional income.
The international Food and Agriculture Organization estimates
more than 7.5 million tons of cowpeas are produced annually
worldwide, with sub-Saharan Africa responsible for about 70
percent of that amount.
“We are already involved in international research projects in
Africa relating to cowpeas,” Payne noted. “It’s exciting to
think where these new activities in College Station and the
research already under way in Africa may lead.” |
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