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Diversity extends herbicide ‘life’ in triple-stacked cotton
D
iversity is one of those ‘how much is good enough’ things. It is often recommended that farmers use ‘as much diversity as possible’ in their weed management program to keep a lid on herbicide resistance, but it is difficult to quantify how much diversity will achieve adequate control. Computer models, like the new ‘Diversity’ model, have proven to give reliable predictions of the real-world outcomes likely to result from the implementation of different weed management programs. The Diversity model tracks the simultaneous evolution of resistance to multiple herbicides, using multiple genetic pathways, in several weed species at once. With triple-stacked herbicide tolerance traits in genetically modified cotton expected to be available to Australian growers within the next five years, the Australian Cotton Research and Development Corporation has invested in research to determine how much diversity in control tactics is required to protect the effective life of this technology. The model suggests that using more diverse strategies in weed control can add 20 years to the effective ‘life’ of this new herbicide tolerance technology. Modelling repeatedly shows that new
SECTION 9 SUSTAINABLE COTTON FARMING
technologies must be supported with several other herbicide and non-herbicide tactics and survivor management given the highest priority. Bayer’s XtendFlex technology confers tolerance to glyphosate, dicamba and glufosinate in cotton and was approved for commercial release by The Office of the Gene Technology Regulator in December 2016. Prior to commercial release, extensive work is underway to understand the system’s fit in the unique Australian environment and to ensure growers will get the most from the technology. XtendFlex cotton varieties are stacked with the Bollgard 3 insect resistance technology, and are expected to provide growers with a robust pest and weed management tool. The concern for weed scientists like Dr David Thornby, Innokas Intellectual Services, is that the triple-stack of herbicide tolerance is already compromised, with glyphosate resistance wellestablished in several weed species on many
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Qualified Local Engineers, with over 40 years experience.
Do it right. Do it once The new Diversity computer model has enabled researchers to test the effect of different weed control programs and scenarios on herbicide resistance in three key weed species, with the aim of prolonging the effective life of the triple-stack herbicide gene technology in irrigated cotton systems.
60 Maitland St, Narrabri, 2390 (02)6792 1265 Jim Purcell 0429 902 584
www.aquatechconsulting.com.au COTTON YEARBOOK 2019 — 129
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