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Narrabri, Australia
July 23, 2003
from
CottonWorld / Cotton
Communications
A
review of Bollgard II (twin gene) technology was presented to
cotton growers, consultants and agronomists at a conference in
Narrabri last week.
The 2003 planting season has been designated as the transition
year for the new twin gene technology, which will replace Ingard
(single gene) technology in the 2004 planting season.
Organised by Cotton Seed Distributors, CSIRO and Monsanto, the
conference covered a range of material on the new technology,
including varietal developments, fibre quality, agronomic, pest,
disease and management issues.
Dr Gary Fitt, chief executive officer of the Cotton CRC said
Ingard cotton had led to a significant reduction in pesticide
use, and Bollgard cotton would continue to strengthen this
benefit, with obvious benefits for farm profits and for the
environment.
He noted that the two independent proteins in Bollgard II cotton
would also dramatically reduce the development of resistance in
the Heliothis population, whereas continued use of Ingard single
protein cotton would place resistance at risk.
However, he warned that continued use of single gene (Bt)
technology to combat pests in other non-cotton crops grown in
areas adjacent to cotton, could enhance the onset of resistance
and undermine the cotton industry's commitment to resistance
strategies.
Dr Greg Constable, senior CSIRO plant breeder, said the breeding
team was developing new lines of conventional and Bollgard II
normal and okra leaf varieties, and was targeting a similar
suite of fibre quality parameters for Bollgard II varieties as
it was with conventional varieties.
These included length greater than 36, strength greater than
30g/tex, and a micronaire range of 3.7 to 4.5.
Dr Constable conceded that high micronaire was a challenge for
Bollgard II growers, due to the strong influence of climate and
management on micronaire, but said new Bollgard varieties would
give growers good tools with which to fight this battle.
While at least four CSIRO/CSD high-yielding Bollgard II
varieties were available for the 2003 plant, a more
comprehensive suite would be available in 2004, including
Roundup Ready types.
Both Dr Fitt and Dr Constable said conventional varieties
would continue to
provide the
foundation for the development of Bollgard II varieties, and
their use would continue in years of low insect pressure, when
the yield benefits of Bollgard II were not as great.
CSD
extensions and development agronomist John Marshall said plant
population studies had shown the importance of plant
establishment in maximising the yield benefits of Bollgard II
varieties.
He noted
that planting time, pest, weed and disease control were
fundamental in achieving high plant establishment.
Monsanto
representative Craig Dunn said the new Bollgard II technology
had been in the pipeline since 1998, with recent developments
including 20ha plots grown under commercial conditions by
growers in all areas from Emerald to Hillston.
Research
had shown that the Bt proteins in Bollgard II lasted much longer
than the single protein in Ingard varieties, averaging 134 days
at several trial sites, but up to 141 days.
In the
past two seasons, when conventional crops in these trials had
required 6-9 insect sprays, Bollgard II varieties had averaged
less than half a spray for Heliothis, with no blowout in sprays
for secondary pests.
While the
jury is still out on yield benefits, Mr Dunn said preliminary
results suggested 8-10% better yields were feasible.
While
acknowledging that Bollgard II cotton offered more robust and
consistent control of Heliothis, he said crop monitoring,
optimising node development and managing high fruit retention
capabilities, via nutrition and timely irrigation, represented a
challenge. |
