![Photo: larva of root not nematode.](/peth04/20041031194816im_/http://ars.usda.gov/is/graphics/photos/oct97/pn-7171i.jpg) Whiplike larva of root-knot nematode, Meloidogyne
incognita, magnified 500X, shown here penetrating a tomato root. Once inside,
the larva establishes a feeding site, which causes a nutrient-robbing gall.
Click the image for more information about it.
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Pepper Lends Its Nematode Resistance to
Double-Cropped Vegetables By
Luis Pons June
23, 2004
The Charleston Belle pepper developed by the
Agricultural Research Service continues
to impress researchers with its ability to resist major root-knot nematodes
afflicting the southern United States.
A recent ARS study not only confirmed the effectiveness and heat
tolerance of Charleston Belle's resistance gene, but also found that the gene
benefits nematode-susceptible vegetables rotated with the pepper.
In the study, led by plant pathologist Judy Thies of the ARS
U.S. Vegetable Laboratory in
Charleston, S.C., Charleston Belle dramatically outperformed its susceptible
parent, Keystone Resistant Giant, in field tests. Not only did it repel
nematodes, it also protected subsequently planted (double-cropped) susceptible
squash and cucumber crops.
The research--described in this month's issue of
Plant Disease--showed
that Charleston Belle exhibited minimal root galling from nematode attack.
Charleston Belle also helped the double-cropped cucumber and squash plants
produce bigger yields and heavier fruit than when the two were grown following
the Keystone variety.
The work was conducted at
Clemson University's Edisto Research
and Education Center in Blackville, S.C., and at the ARS
Crop Protection and Management
Research Unit in Tifton, Ga. ARS is the U.S. Department of Agriculture's
chief scientific research agency.
Charleston Belle peppers--released in 1997 by ARS Vegetable
Laboratory geneticist Richard Fery--get their resistance from the N gene, which
was obtained from a resistant pimiento pepper and placed into Keystone
cultivars to create Charleston Belle. The gene controls resistance to three
major root-knot nematode species: southern (Meloidogyne incognita), peanut (M.
arenaria) and javanese (M. javanica).
The pepper's resistance may aid growers who, next year, must
fight root-knot nematodes without use of methyl bromide. This pesticide will be
banned Jan. 1 because of its ozone-depleting properties.
Other, independent studies have shown that nematode-resistant
vegetable plants--notably tomatoes--can help shield double-cropped vegetables
from nematode attack. In the ARS study, cucumber yields were 87 percent heavier
and numbers of fruit were 85 percent higher when grown after Charleston Belle
than after Keystone. Squash yields were 55 percent heavier, with 50 percent
more fruit. |