Abstract
The over-reliance and continued use of glyphosate as the sole mechanism for weed control has led to the selection of glyphosate-resistant weeds. New trait technology incorporating 2,4-D tolerance in soybean will provide an alternative method to control weeds that are hard to control with glyphosate alone and reduce selection pressure by tank mixing herbicides with 2,4-D, but the response of aryloxyalkanoate dioxygenase-12 (AAD-12) transformed soybean have not been evaluated. In addition, off-site movement of auxinic herbicides on sensitive soybean will be of greater concern as 2,4-D and dicamba will be applied at a field-scale level during the peak growing season with new transgenic crops becoming commercially available in the near future. The purpose of my research was to quantify the effects of 2,4-D timing and rates on AAD-12 soybean yield components and AAD-12 protein expression; characterize the effects of dicamba and 2,4-D rates on sensitive soybean plants; and analyze the effect of 2,4-D plus glyphosate on summer annual weeds. It is conclude that 1) AAD-12 soybean plants can tolerate up to 2,240 g ha-1 2,4-D. Seed yield, seed mass, pod number, seed number, seed per pod, reproductive node number, pods per reproductive node, node number, and percent reproductive nodes were not affected by 2,4-D when applied at the V5, R2, or the V5 followed by the R2 soybean growth stages of AAD-12 soybean plants. 2) The youngest fully emerged trifoliate in the DAS-68416-4 event had the highest AAD-12 expression, with means ranging from 369 to 390 ng cm-2, while the older leaves maintained a lower level of expression, 171 to 211 ng cm-2. The youngest leaves of event DAS-21606-3 had the highest level of AAD-12 protein expression (205 to 225 ng cm-2), while the level of AAD-12 was lower in older leaves (71 to 149 ng cm-2). In general, 2,4-D treatments did not reduce AAD-12 protein expression at 3, 7, 14, and 21 days after treatment; however, in a few instances AAD-12 protein expression was increased or decreased by 8 to 11% after 2,4-D treatment. 3) Glyphosate at rates ≥ 840 g ha-1 controlled giant ragweed, common lambsquarters, common waterhemp, and velvetleaf by 94 to 100%. Giant ragweed was controlled 99 to 100% by 2,4-D alone when rates were ≥ 280 g ha-1. Common lambsquarters, common waterhemp, and velvetleaf control increased as 2,4-D rates increased, with 1,120 g ha-1 providing 90 to 94% control. 4) Sensitive soybean seed yield was reduced by 5% when 87 to 116 g ha-1 2,4-D was applied and a 10% reduction was caused by 149 to 202 g ha-1 2,4-D. 5) Dicamba treatments applied to sensitive soybean reduced seed yield by 5% from 0.042 to 0.528 g ha-1 and a 10% reduction was caused by 0.169 to 1.1 g ha-1 dicamba. Path analysis indicated that seeds m-2, pods m-2, main stem reproductive nodes m-2, and main stem nodes m -2 were the most influential yield components in seed yield formation when either 2,4-D or dicamba treatments were applied to sensitive soybean plants. The introduction of 2,4-D-tolerant crops will allow add an addition method to control weeds that are resistant to glyphosate while not altering reproduction, but precautions need to be taken to avoid injury to nearby sensitive plants.
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Claims 14
Claim · model-written summary
AAD-12 soybean tolerated up to 2,240 g ha-1 2,4-D.
- Taxon
- soybean
Glycine maxe0 - Material
- AAD-12e0
- Outcome
- toleratee0
- Value
- 2,240 g ha-1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“AAD-12 soybean plants can tolerate up to 2,240 g ha-1 2,4-D”
Claim · model-written summary
2,4-D did not affect the listed yield components of AAD-12 soybean at V5 or R2 timings.
- Taxon
- soybeanGlycine maxe0
- Material
- AAD-12e0
- Treatment
- 2,4-De0
- Outcome
- Seed yield, seed mass, pod number, seed number, seed per pod, reproductive node number, pods per reproductive node, node number, and percent reproductive nodese0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seed yield, seed mass, pod number, seed number, seed per pod, reproductive node number, pods per reproductive node, node number, and percent reproductive nodes were not affected by 2,4-D when applied at the V5, R2, or the V5 followed by the R2 soybean growth stages of AAD-12 soybean plants”
Claim · model-written summary
The youngest DAS-68416-4 trifoliate had the highest AAD-12 expression.
- Taxon
- soybeanGlycine maxt0
- Material
- DAS-68416-4e0
- Organ / stage
- youngest fully emerged trifoliatee0
- Gene
- AAD-12e0
- Outcome
- AAD-12 expressione0
- Direction
- higheste0
- Value
- 369 to 390 ng cm-2e0
- Qualifier
- 171 to 211 ng cm-2e0
- Comparator
- older leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The youngest fully emerged trifoliate in the DAS-68416-4 event had the highest AAD-12 expression, with means ranging from 369 to 390 ng cm-2, while the older leaves maintained a lower level of expression, 171 to 211 ng cm-2”
t0“soybean”
Claim · model-written summary
The youngest DAS-21606-3 leaves had highest AAD-12 expression.
- Taxon
- soybeanGlycine maxt0
- Material
- DAS-21606-3e0
- Organ / stage
- youngest leavese0
- Gene
- AAD-12e0
- Outcome
- AAD-12 protein expressione0
- Direction
- higheste0
- Value
- 205 to 225 ng cm-2e0
- Qualifier
- 71 to 149 ng cm-2e0
- Comparator
- older leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The youngest leaves of event DAS-21606-3 had the highest level of AAD-12 protein expression (205 to 225 ng cm-2), while the level of AAD-12 was lower in older leaves (71 to 149 ng cm-2)”
t0“soybean”
Claim · model-written summary
2,4-D generally did not reduce AAD-12 protein expression after treatment.
- Taxon
- soybeanGlycine maxt0
- Treatment
- 2,4-De0
- Gene
- AAD-12e0
- Outcome
- AAD-12 protein expressione0
- Direction
- did not reducee0
- Qualifier
- 3, 7, 14, and 21 days after treatmente0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In general, 2,4-D treatments did not reduce AAD-12 protein expression at 3, 7, 14, and 21 days after treatment”
t0“soybean”
Claim · model-written summary
In a few cases 2,4-D changed AAD-12 expression by 8 to 11%.
- Taxon
- soybeanGlycine maxt0
- Treatment
- 2,4-De0
- Gene
- AAD-12e0
- Outcome
- AAD-12 protein expressione0
- Direction
- increased or decreasede0
- Value
- 8 to 11%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in a few instances AAD-12 protein expression was increased or decreased by 8 to 11% after 2,4-D treatment”
t0“soybean”
Claim · model-written summary
Glyphosate controlled four annual weeds by 94 to 100% at rates of at least 840 g ha-1.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Glyphosate at rates ≥ 840 g ha-1e0
- Interactor
- giant ragweed
.jpg?width=60)
Ambrosia trifidae0weed - Outcome
- controlled giant ragweed, common lambsquarters, common waterhemp, and velvetleafe0
- Direction
- controllede0
- Value
- 94 to 100%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Glyphosate at rates ≥ 840 g ha-1 controlled giant ragweed, common lambsquarters, common waterhemp, and velvetleaf by 94 to 100%”
t0“soybean”
Claim · model-written summary
2,4-D alone controlled giant ragweed by 99 to 100% at rates of at least 280 g ha-1.
- Taxon
- soybeanGlycine maxt0
- Treatment
- 2,4-D alonee0
- Interactor
- Giant ragweedAmbrosia trifidae0weed
- Outcome
- Giant ragweed was controllede0
- Direction
- controllede0
- Value
- 99 to 100%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Giant ragweed was controlled 99 to 100% by 2,4-D alone when rates were ≥ 280 g ha-1”
t0“soybean”
Claim · model-written summary
Control of common lambsquarters, common waterhemp and velvetleaf rose with 2,4-D rate, reaching 90 to 94%.
- Taxon
- soybeanGlycine maxt0
- Treatment
- 2,4-D ratese0
- Interactor
- Common lambsquarters
Chenopodium albume0weed - Outcome
- Common lambsquarters, common waterhemp, and velvetleaf controle0
- Direction
- increasede0
- Value
- 90 to 94%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Common lambsquarters, common waterhemp, and velvetleaf control increased as 2,4-D rates increased, with 1,120 g ha-1 providing 90 to 94% control”
t0“soybean”
Claim · model-written summary
Sensitive soybean seed yield fell 5% with 87 to 116 g ha-1 2,4-D.
- Taxon
- soybeanGlycine maxe0
- Material
- Sensitive soybeane0
- Treatment
- 87 to 116 g ha-1 2,4-De0
- Outcome
- seed yielde0
- Direction
- reducede0
- Value
- 5%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sensitive soybean seed yield was reduced by 5% when 87 to 116 g ha-1 2,4-D was applied”
Claim · model-written summary
Sensitive soybean seed yield fell 10% with 149 to 202 g ha-1 2,4-D.
- Taxon
- soybeanGlycine maxt0
- Treatment
- 149 to 202 g ha-1 2,4-De0
- Outcome
- seed yielde1
- Direction
- reductione0
- Value
- 10%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a 10% reduction was caused by 149 to 202 g ha-1 2,4-D”
e1“Sensitive soybean seed yield was reduced by 5%”
t0“soybean”
Claim · model-written summary
Sensitive soybean seed yield fell 5% with 0.042 to 0.528 g ha-1 dicamba.
- Taxon
- soybeanGlycine maxe0
- Treatment
- Dicamba treatmentse0
- Outcome
- seed yielde0
- Direction
- reducede0
- Value
- 5%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Dicamba treatments applied to sensitive soybean reduced seed yield by 5% from 0.042 to 0.528 g ha-1”
Claim · model-written summary
Sensitive soybean seed yield fell 10% with 0.169 to 1.1 g ha-1 dicamba.
- Taxon
- soybeanGlycine maxt0
- Treatment
- 0.169 to 1.1 g ha-1 dicambae0
- Outcome
- reductione0
- Direction
- reductione0
- Value
- 10%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a 10% reduction was caused by 0.169 to 1.1 g ha-1 dicamba”
t0“soybean”
Claim · model-written summary
Seeds, pods, reproductive nodes and main-stem nodes per square metre were influential components of yield under herbicide treatment.
- Taxon
- soybeanGlycine maxe0
- Treatment
- 2,4-D or dicamba treatmentse0
- Outcome
- seed yield formatione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Path analysis indicated that seeds m-2, pods m-2, main stem reproductive nodes m-2, and main stem nodes m -2 were the most influential yield components in seed yield formation when either 2,4-D or dicamba treatments were applied to sensitive soybean plants”
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