www.checkbiotech.org ; www.raupp.info ; www.czu.cz

A new corn rootworm trait that is in the late stages of regulatory approval
has demonstrated excellent control, consistency and yield results in
extensive university and Syngenta testing, March 2006.

Event MIR604*, which Syngenta seeks to commercialize under its Agrisure?
brand of traits, has shown an average 32 bushel-per-acre yield advantage in
rootworm-infested fields and, in Syngenta studies, no yield drag compared to
the hybrid isoline.

MIR604 is being reviewed by the Department of Agriculture, the Food and Drug
Administration (FDA) and in experimental trials under the Environmental
Protection Agency (EPA). If it is approved, Syngenta hopes to market MIR604
as Agrisure RW, individually and in stacks, through elite hybrids of its
Garstˇ, Golden Harvestˇ and NKˇ brands to growers in the U.S. for planting
in the 2007 season. Syngenta already markets Agrisure GT (glyphosate
tolerance), Agrisure CB/LL (season-long corn borer control with Libertyˇ
herbicide tolerance) and Agrisure GT/CB/LL (stacked traits).

?MIR604, the Agrisure rootworm event, has exceeded our expectations in
rigorous testing conducted throughout the Midwest Corn Belt,? says Jack
Bernens, head, Agrisure traits. ?In addition to demonstrating effective,
consistent protection from corn rootworm, it has been placed in leading
Syngenta genetics utilizing an industry-leading trait conversion process
that will ensure hybrids with this trait will reach their full yield
potential.?

Offering excellent built-in control of corn rootworm, MIR604 is a modified
full length Cry3Aa gene from Bacillus thuringiensis (Bt). The modification
extends the activity of this gene to Mexican, northern and western corn
rootworms. MIR604 controls newly hatched rootworms through the first larval
instar as they begin to feed on corn roots. The larvae are eliminated as
soon as they consume the unique Bt protein in the roots.

More than 60 trials over a three-year period were conducted across the Corn
Belt by nine Midwestern universities and Syngenta(1). In trials with
economic pest pressure, hybrids with MIR604provided an average root rating
of 0.22 (on a 0-3 Node-Injury Scale, with 0.01 representing no feeding
damage and 3.00 being the highest level of root damage), well below the
industry-accepted economic threshold of 0.75. Conventional check plots
showed an average root rating of 1.51 over the same time period. The
rootworm event also provided more effective control when compared to
standard insecticide treatments.

MIR604 had an 89 percent consistency of control averaged over the same
trials and under varying weather conditions. Consistency is a measure of the
frequency of when the individual roots average equal to or less than 0.5. In
comparison, untreated control plots averaged 33 percent consistency.

In areas of high insect pressure, MIR604 averaged a 0.37 in root rating and
79 percent consistency, while the untreated plots averaged a 2.3 rating and
12 percent consistency.

University entomologists who have conducted research on the new trait in
their respective state over the past three years are encouraged at the
results. In Kansas, for example, trials demonstrated outstanding control
under extreme rootworm pressure. ?We?ve had a damage rating of 2.00 in the
untreated plots and virtually no damage in the MIR604 fields,? says Gerald
Wilde, Kansas State University extension entomologist. ?The new trait
performed very well, even under severe pressure.?

Further east in Indiana, Larry Bledsoe, entomologist at Purdue University,
noted that trials in 2005 were subjected to heavy rootworm pressure and a
prolonged period of drought. ?The MIR604 plots performed well, while the
conditions in the check plots allowed rootworms to feed faster than the
roots were growing,? Bledsoe noted.

Bernens notes that, if it is approved, MIR604 would be placed in elite
genetics utilizing an industry-leading trait conversion process that allows
the hybrids to reach their full yield potential. The Syngenta system of
marker-assisted breeding helps ensure proper conversion and maintains the
efficacy of the trait.

?Syngenta has taken the time to find the right way to convert this gene to
maximize the potential of the rootworm trait and place it in the highest
quality hybrids,? Bernens says. ?This will also allow growers to reap the
full benefits of the trait ? unparalleled control of rootworms and maximum
yield potential.?

MIR604 is one of many new products in development through Syngenta biotech
research and development. Agrisure GT (glyphosate-tolerant corn) and
Agrisure CB (protection against corn borers) and the stack of Agrisure GT/CB
were the first Syngenta traits to be introduced commercially in 2005. Other
innovative stacks will follow.

[www.syngenta.com]

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