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January 16, 2008
Source:
CropBiotech Update
Genetically modified, insect
resistant maize was first cultivated in Spain in 1998. GM maize
growing areas reached 64,200 ha in 2006, with 85 percent of the
transgenic maize crop originating in the northeastern region of
the country. Spain is the largest GM maize producer in the
European Union. Bt-maize has proved to be an excellent means to
control corn borers. Increased densities of aphids and
leafhoppers, however, have been recorded in some Bt-maize
fields. These non-target arthropods are vectors of viruses
infecting the crop. In a study published by Transgenic Research,
researchers from the University of Lleida evaluated the changes
in the distribution and abundance of maize viruses in Spain
after 9 years of large-scale cultivation of Bt-maize.
The maize dwarf mosaic virus (MDMV) was found to be the
predominant virus in Bt-areas, and maize rough dwarf virus
(MRDV) was found to be common in non-Bt-areas, with MRDV an
emergent virus in both types of areas. Data obtained from 2001
to 2006 in experimental fields showed non-significant
differences between the infection rates exhibited by two
generations of Bt varieties and the non-transformed isogenics
varieties for any of the viruses. The researchers concluded that
differences in virus distribution are linked to the genetic
background of the maize varieties and the distribution of virus
reservoirs rather than to Bt-maize cultivation.
The full article is accessible at
http://dx.doi.org/10.1007/s11248-008-9231-2
Impact of 9 years of
Bt-maize cultivation on the distribution of maize viruses
Maria Angeles Achon and Natalia Alonso-Dueñas
Departamento de Producción Vegetal y Ciencia Forestal,
Universitat de Lleida, Spain
Journal Transgenic Research
Publisher Springer Netherlands
ISSN 0962-8819 (Print) 1573-9368 (Online)
DOI 10.1007/s11248-008-9231-2
Abstract
This study assesses the effect of Bt-maize on the
distribution of maize viruses. Random surveys were conducted
in Spain between 2001 and 2006 to evaluate the occurrence of
maize viruses in Bt-maize cultivation areas and in areas
where this crop had not been introduced. Maize dwarf mosaic
virus (MDMV) was the predominant virus in Bt-areas, and
Maize rough dwarf virus (MRDV) was the most predominant one
in non-Bt-areas, with MRDV an emergent virus in both types
of areas. A decline in the occurrence of MDMV and an
increase in that of Sugarcane mosaic virus was observed in
Bt-areas. Additionally, data obtained over 6 years in
experimental fields showed non-significant differences
between the infection rates exhibited by two generations of
Bt varieties and the non-transformed isogenics varieties for
any of the viruses. Our data suggest that differences in
virus distribution are linked to the genetic background of
the maize varieties and the distribution of virus reservoirs
rather than to Bt-maize cultivation.
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