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April 27, 2007
Source:
CropBiotech Update
Crop to weed transmission of
glyphosate resistance via gene flow has been frequently
researched but little information is available on weed to weed
interactions. To determine the possible occurrence of weed to
weed transfer of the glyphosate resistance, researchers at the
Iowa State University and
University of Delaware
examined hybridization in Conyza, a prevalent weed species in
the Midwestern United States.
The researchers observed that hybridization and transfer of
herbicide resistance can occur between C. canadensis and C.
ramosissima. The researchers have determined that approximately
3% of ova were fertilized by pollen of the opposing species and
produced viable seeds. The interspecific hybrids were found to
have intermediate phenotype between the parents but exhibit
superior resistance to glyphosate compared to the herbicide
resistant C. canadensis parent.
The possibility of introgressive hybridization suggest
complications in the management of glyphosate resistant weed
populations in glyphosate resistant crops and the containment of
glyphosate resistance genes within these agroecosystems. The
researchers reiterated that weed control should be combined with
alternative management tactics to mitigate the evolution of
herbicide resistance in the current agroecosystems.
The paper published by the
American Journal of Botany, can be accessed at
http://www.amjbot.org/cgi/content/abstract/94/4/660. |
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