ChangingCottonLandscapeNeilForrester

the introduction of Roundup Ready Flex cotton in 2006. However, there may be volatility and
drift issues with dicamba herbicide which will have to be closely watched and managed if
required.
Bayer is proposing a 2-gene stacked Glytol / Liberty Link herbicide tolerant technology. Glytol
will be Bayer’s own glyphosate resistance technology which will be stacked with their current
Liberty Link (glufosinate resistant) technology.
Dow has also announced the development of its own 2-gene stacked DHT herbicide tolerant
technology. DHT stands for Dow Agrosciences Herbicide Tolerance Trait and is based on
resistance to 2 separate herbicide classes: the synthetic auxin growth regulators (HRAC mode
of action class O) and the aryloxy phenoxy propionate or “fop” herbicides (HRAC mode of action
class A). Once again, this should help to manage potential herbicide resistance problems but
the auxinic herbicides do present potential volatility and drift management issues.
Syngenta is also developing its own glyphosate tolerant cotton technology (Touchdown
Tolerance).
Dupont has also recently announced the development of its new OPTIMUM GAT herbicide
tolerance technology for cotton and other field crops. OPTIMUM is an umbrella brand name and
GAT stands for Glyphosate ALS Tolerant which is based on resistance to 2 separate herbicide
classes: glyphosate and the acetolactate synthase (ALS) inhibitor herbicides such as the
sulfonylureas and imidazolinones (HRAC mode of action class B). The OPTIMUM technology is
based on DuPont’s proprietary “gene shuffling” technique to optimise expression/activity of
candidate transgenes. Once again, this will certainly help in the management of potential
herbicide resistance problems.
However, it should also be noted that in Pakistan, weeds serve an important function for the
local villagers who harvest them for forage for their household livestock. This source of historical
“free fodder” should be recognized and alternatives devised if and when herbicide tolerant
technologies are adopted, so that underprivileged villagers are not disadvantaged.
The recommendation for herbicide tolerant technologies in Pakistan is to go straight to
Monsanto’s Roundup Ready Flex glyphosate tolerant cotton and to stack it with double gene
Bollgard 2 or triple gene Bollgard 3 (to be discussed later). There is no point in delaying as all
these technologies are available here and now for introgression into local germplasm. Other
potential technology providers should also be consulted.
22