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November 14, 2008
Source:
CropBiotech Update
The root-knot nematode
(Meloidogyne incognita), a biotrophic parasite of many crops,
including tomato, cotton and coffee, is responsible for global
agricultural losses amounting to more than US$ 150 billion
annually. The ominpresent worm is usually controlled by applying
methyl bromide, an odorless, colorless gas that has severe
negative effects in the environment. The pesticide has been
banned for use in the United States.
Scientists from the US Department of Agriculture's Agricultural
Research Service (ARS) developed varieties of bell pepper
resistant to the root-knot nematode. In a paper published by
HortScience, a team of researchers led by Judy Thies tested the
stability of the worm-resistant bell pepper varieties
'Charleston Belle' and 'Carolina Wonder'. Good news for pepper
growers: the scientists found out that the two varieties are
viable alternatives to methyl bromide for managing southern
root-knot nematode in sub-tropical environments. It is important
to establish whether the peppers' resistance to the nematode
breaks down when they are grown in hot environments.
Source:
Hortscience
Stability of Resistance to
Root-knot Nematodes in ‘Charleston Belle’ and ‘Carolina
Wonder’ Bell Peppers in a Sub-tropical Environment
Judy A. Thies1,4
U.S. Vegetable Laboratory, USDA, ARS, 2700 Savannah Highway,
Charleston, SC 29414-5334
Don W. Dickson2
University of Florida, Entomology and Nematology Department,
Gainesville, FL
Richard L. Fery3
U.S. Vegetable Laboratory, USDA, ARS, Charleston, SC
29414-5334
ABSTRACT Two
root-knot nematode-resistant bell pepper cultivars,
‘Charleston Belle’ and ‘Carolina Wonder’ (Capsicum annuum L.
var. annuum], and their susceptible parents, ‘Keystone
Resistant Giant’ and ‘Yolo Wonder B’, were compared for
managing the southern root-knot nematode [Meloidogyne
incognita (Chitwood) Kofoid and White] in fall and spring
tests at Citra, FL. In the fall test, ‘Charleston Belle’ and
‘Carolina Wonder’ exhibited minimal root galling and
nematode reproduction, and ‘Keystone Resistant Giant’ and
‘Yolo Wonder B’ exhibited severe root galling and high
nematode reproduction. Fruit yield of ‘Charleston Belle’ was
97% greater than yields of the two susceptible cultivars (P
0.006). In the spring test, one-half of the plots were
treated with methyl bromide/chloropicrin before planting the
same four bell pepper cultivars. ‘Keystone Resistant Giant’
and ‘Yolo Wonder B’ grown in untreated control plots
exhibited severe root galling and high nematode
reproduction, but the other six cultivar x methyl bromide
combinations exhibited minimal root galling and nematode
reproduction. Although soil temperatures (10-cm depth) were
greater than 30 °C on 78 days and 57 days during the Fall
2002 and Spring 2003 trials, respectively, resistance did
not break in ‘Charleston Belle’ and ‘Carolina Wonder’ in
either test. These results demonstrate that root-knot
nematode-resistant cultivars such as Charleston Belle and
Carolina Wonder are viable alternatives to methyl bromide
for managing southern root-knot nematode in bell pepper in
sub-tropical environments.
Source:
http://hortsci.ashspublications.org/cgi/content/abstract/43/1/188
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