Fruiting morphology was altered when glyphosate-resistant cotton was
sprayed with glyphosate.
Manipulated Organism:
Cotton (Gossypium hirsutum).
Inserted Transgenes:
CP4 EPSPS gene cloned from Agrobacterium, which produces an
herbicide-resistant version of the enzyme targeted by the herbicide
glyphosate (Roundup).
Goal of This Study:
To investigate whether the timing and method of glyphosate application
to glyphosate-resistant (GR) cotton affects fruiting morphology, yield,
and fiber quality.
Results of This Study:
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Several differences in fruiting morphology, such as a reduction in
the number of early fruits (bolls), were observed in the field when
GR plants were treated with glyphosate. The most pronounced differences
were seen with late (beyond the four-leaf stage) foliar applications of
glyphosate, which are technically not allowed (off-label), but even
"treatments applied within label guidelines may unpredictably impact
fruit retention in certain years or conditions" (p. 28).
-
At one field site, a small (6%) but statistically significant reduction
in seed cotton yield was observed when GR plants received late (off-label)
foliar applications of glyphosate.
Source:
Pline-Srnic, W. A., K. L. Edmisten, J. W. Wilcut, R. Wells et al. (2004).
"Effect of Glyphosate on Fruit Retention, Yield, and Fiber Quality of
Glyphosate Resistant Cotton," Journal of Cotton Science vol. 8,
pp. 24-32.
Author Affiliations:
Syngenta; North Carolina State University.
Funding:
North Carolina Cotton Growers; Cotton Incorporated.
Product Status:
GR cotton is grown worldwide, including since 1997 in the U.S.
Copyright 2009 The Nature
Institute.
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