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GM cotton has reduced pest resistance
The Journal of Cotton Science 4:232-236 (2000)
Plant Pathology and Nematology
Root-Knot Nematode Reproduction and Root Galling Severity on Related
Conventional and Transgenic Cotton Cultivars
Patrick D. Colyer,* Terrence L. Kirkpatrick, W. David Caldwell, and
Philip R. Vernon
ABSTRACT
The root-knot nematode (Meloidogyne incognita Kofoid & White), a widespread
and serious pest of cotton (Gossypium hirsutum L.) throughout the
Cotton Belt, is managed in many areas in part through cultivar resistance.
Recently, commercial cotton cultivars modified with genes for resistance
to the tobacco budworm (Heliothis virescens F.), to glyphosate herbicide
(e.g., Roundup, Monsanto, St. Louis, MO), or in some cases to both the
budworm and the herbicide have been released. The objective of this study
was to compare the root-knot nematode resistance or susceptibility of
several transgenic cotton cultivars with that of their unmodified parent
cultivars. The cultivars were evaluated in a field naturally infested
with the root-knot nematode and in a growth room in pots infested with
the
nematode. A dramatic increase in root-knot nematode susceptibility was
seen in the transgenic cultivar, Paymaster 1560 BG, compared with its
nontransgenic parent, Paymaster 1560. Although only a limited number of
cultivars were studied, the data demonstrate that differences in
susceptibility to the root-knot nematode exist between some transgenic
cultivars and their nontransgenic parents. These data indicate the importance
of screening transgenic cultivars for resistance to pests other than the
particular pest species targeted by the genetic modification before the
transgenic cultivars are recommended for planting.
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