Stewardship/Management of Transgenic Products Micheal D. K. Owen Iowa State University Ames, IA...
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Transcript of Stewardship/Management of Transgenic Products Micheal D. K. Owen Iowa State University Ames, IA...
Stewardship/Management of Stewardship/Management of Transgenic ProductsTransgenic Products
Micheal D. K. OwenMicheal D. K. OwenIowa State UniversityIowa State UniversityAmes, IA 50011 USAAmes, IA 50011 [email protected]@iastate.edu
www.weeds.iastate.eduwww.weeds.iastate.edu
IntroductionIntroduction
Stewardship reflects management Stewardship reflects management decisions that will enhance and preserve a decisions that will enhance and preserve a particular crop trait particular crop trait andand are economically are economically rewarding rewarding
Some traits impart selection pressure Some traits impart selection pressure upon the pest complex for which they are upon the pest complex for which they are designed (i.e. BT)designed (i.e. BT)
Traits for herbicide resistance in crops are Traits for herbicide resistance in crops are “benign” and do not exert selection “benign” and do not exert selection pressure – the pressure – the herbicideherbicide exerts the exerts the selection pressure selection pressure
IntroductionIntroduction
The “stewardship” efforts initiated by The “stewardship” efforts initiated by the Weed Science group and the Weed Science group and supported by the Iowa Grain Quality supported by the Iowa Grain Quality Initiative represent two areas:Initiative represent two areas:• Evaluation and monitoring of weeds with Evaluation and monitoring of weeds with
variable responses to glyphosatevariable responses to glyphosate• Development of weed management Development of weed management
strategies for specific output traits or strategies for specific output traits or specialty traitsspecialty traits
Glyphosate stewardshipGlyphosate stewardship Clean fields do not necessarily equate to good weed Clean fields do not necessarily equate to good weed
managementmanagement• The objective of weed management is to The objective of weed management is to
protect crop yield potentialprotect crop yield potential Diversified weed management tactics provide Diversified weed management tactics provide
significant benefits to glyphosate-based systemssignificant benefits to glyphosate-based systems• Residual herbicides applied EPP or PRE are Residual herbicides applied EPP or PRE are
important components of a weed management important components of a weed management programprogram
• Mechanical weed control tactics should be includedMechanical weed control tactics should be included Timely application of tactics is critical for all weed Timely application of tactics is critical for all weed
management programsmanagement programs
Stewardship and Grower AttitudesStewardship and Grower Attitudes
Considerable effort in providing Considerable effort in providing information about the evolution of information about the evolution of herbicide resistanceherbicide resistance
These efforts have been marginally These efforts have been marginally effective (e.g. ALS resistance)effective (e.g. ALS resistance)
66% of Indiana growers expressed only a 66% of Indiana growers expressed only a low to moderate concern about glyphosate low to moderate concern about glyphosate resistanceresistance
Only 38% recognized the role of repeat Only 38% recognized the role of repeat MOAs on selection pressureMOAs on selection pressure
Adoption of glyphosate-resistant crops Adoption of glyphosate-resistant crops continues to risecontinues to rise
The Glyphosate DecadeThe Glyphosate Decade
Source: University & USDA reports
2000: Horseweed in DE, MD, NJ
1998: Rigid ryegrass in CA
2001: Horseweed in TN, KY
2002: Horseweed in IN, OH
2002: “Variably tolerant” waterhemp in IA, IL, MO
2003: Horseweed in AR, MS, NC
2004: Common ragweed in MO
2005: Horseweed in CA
2004: Italian ryegrass in OR2005: Palmer pigweed
suspected in NC2005: Palmer pigweed in GA and TN
2005: Common waterhemp in MO
2006: Horseweed in NE
Weeds to watch in IowaWeeds to watch in Iowa
Common lambsquartersCommon lambsquarters Giant ragweedGiant ragweed Common waterhempCommon waterhemp Asiatic dayflowerAsiatic dayflower MarestailMarestail Others?Others?
Figure 2. Percentage of Asiatic dayflower control
0
5
10
15
20
25
30
35
2-4 4-8 8-10 10-12 12-16
growth stage (number of leaves)
% c
ontro
lControl
6 oz/acre
12 oz/acre
24 oz/acre
48 oz/acre
96 oz/acre
Specialty grains/high value cropsSpecialty grains/high value crops
Several field experiments have been Several field experiments have been conducted on inbreds, cultivars, and conducted on inbreds, cultivars, and output trait cropsoutput trait crops
Experiments focus on evaluating the Experiments focus on evaluating the potential for existing and new herbicides potential for existing and new herbicides to manage weeds in these cropsto manage weeds in these crops
Particular attention is given to the relative Particular attention is given to the relative tolerance of the crops to the herbicidestolerance of the crops to the herbicides
Past efforts had included considerable Past efforts had included considerable experimentation with popcorn varietiesexperimentation with popcorn varieties
2006 efforts2006 efforts
Experiments with 8 low lin soybean Experiments with 8 low lin soybean varietiesvarieties
Experiments with 3 white corn Experiments with 3 white corn varieties, 1 high oil and 1 waxy varieties, 1 high oil and 1 waxy varietyvariety
Experiments on 7 sensitive and very Experiments on 7 sensitive and very sensitive inbredssensitive inbreds
2006 efforts2006 efforts
Registered and experimental Registered and experimental herbicides were included in the herbicides were included in the experimentsexperiments
Application timing, herbicide Application timing, herbicide combinations and rates were combinations and rates were includedincluded
Results available at Results available at www.weeds.iastate.eduwww.weeds.iastate.edu