Abstract
Fifteen field experiments were conducted from 2009 to 2012 in Ontario, Canada and Michigan, USA to determine the tolerance of corn (Zea mays L.) to early (spike or 1- to 2-leaf stage) or late (8- or 10-leaf stage) applications of 900, 1800, 3600, or 7200 g·ae·ha-1 of glyphosate. Postemergence applications were evaluated for corn injury, cob length and deformity, crop moisture at harvest, and yield in the absence of weed competition. In the early application experiment, no visible injury was detected with applications of up to 3600 g·ae·ha-1; however, 1.4% injury was observed 4 weeks after treatment (WAT) when 7200 g·ae·ha-1 was applied to 1- to 2-leaf stage corn. Yet by harvest, the observed injury was transient as yields were similar to the untreated control regardless of glyphosate dose or timing. In the late application experiment, visible injury tended to increase with glyphosate dose. In addition, for corn treated with 7200 g·ae·ha-1 at the 10-leaf stage, injury increased over time as 6%, 11%, and 12% injury was observed 1, 2, and 4 WAT, respectively. Similar to the visible injury of vegetative tissue, cob deformity and reductions in yield tended to increase with glyphosate dose, but this response varied and the data were pooled into two environment groups. For example, in one environment group, corn treated with 7200 g·ae·ha-1 at the 8- and 10-leaf stage had a 9.5% and 14.6% reduction in yield, respectively. Whereas in another environment group, corn yields were similar to the untreated control regardless of glyphosate dose or timing. This research demonstrated that commercially available corn hybrids have tolerance to glyphosate at doses greater than what has been previously published or could reasonably be expected during spray overlaps in a field.
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Claims 12
Claim · model-written summary
Early glyphosate applications up to 3600 g·ae·ha-1 caused no visible corn injury.
- Taxon
- corn
Zea mays subsp. mayst0 - Treatment
- up to 3600 g·ae·ha-1e0
- Outcome
- visible injurye0
- Direction
- no visible injurye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Corn”
e0“no visible injury was detected with applications of up to 3600 g·ae·ha-1”
Claim · model-written summary
Applying 7200 g·ae·ha-1 at the 1- to 2-leaf stage caused 1.4% injury at four weeks.
- Taxon
- cornZea mays subsp. mayse0
- Organ / stage
- 1- to 2-leaf stagee0
- Treatment
- 7200 g·ae·ha-1e0
- Outcome
- injurye0
- Value
- 1.4%e0
- Qualifier
- 4 weeks after treatment (WAT)e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“1.4% injury was observed 4 weeks after treatment (WAT) when 7200 g·ae·ha-1 was applied to 1- to 2-leaf stage corn”
Claim · model-written summary
Early treated corn had yields similar to untreated controls regardless of dose or timing.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- glyphosatee0
- Outcome
- yieldse0
- Direction
- similare0
- Comparator
- untreated controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Corn”
e0“by harvest, the observed injury was transient as yields were similar to the untreated control regardless of glyphosate dose or timing”
Claim · model-written summary
Late application injury tended to increase with glyphosate dose.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- glyphosate dosee0
- Outcome
- visible injurye0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Corn”
e0“visible injury tended to increase with glyphosate dose”
Claim · model-written summary
At the 10-leaf stage, 7200 g·ae·ha-1 glyphosate caused 6% injury one week after treatment.
- Taxon
- cornZea mays subsp. mayse0
- Organ / stage
- 10-leaf stagee0
- Treatment
- 7200 g·ae·ha-1e0
- Outcome
- injurye0
- Direction
- increasede0
- Value
- 6%e0
- Qualifier
- 1, 2, and 4 WATe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn treated with 7200 g·ae·ha-1 at the 10-leaf stage, injury increased over time as 6%, 11%, and 12% injury was observed 1, 2, and 4 WAT, respectively”
Claim · model-written summary
At the 10-leaf stage, 7200 g·ae·ha-1 glyphosate caused 11% injury two weeks after treatment.
- Taxon
- cornZea mays subsp. mayse0
- Organ / stage
- 10-leaf stagee0
- Treatment
- 7200 g·ae·ha-1e0
- Outcome
- injurye0
- Direction
- increasede0
- Value
- 11%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn treated with 7200 g·ae·ha-1 at the 10-leaf stage, injury increased over time as 6%, 11%, and 12% injury was observed 1, 2, and 4 WAT, respectively”
Claim · model-written summary
At the 10-leaf stage, 7200 g·ae·ha-1 glyphosate caused 12% injury four weeks after treatment.
- Taxon
- cornZea mays subsp. mayse0
- Organ / stage
- 10-leaf stagee0
- Treatment
- 7200 g·ae·ha-1e0
- Outcome
- injurye0
- Direction
- increasede0
- Value
- 12%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn treated with 7200 g·ae·ha-1 at the 10-leaf stage, injury increased over time as 6%, 11%, and 12% injury was observed 1, 2, and 4 WAT, respectively”
Claim · model-written summary
Cob deformity tended to increase with glyphosate dose.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- glyphosate dosee0
- Outcome
- cob deformitye0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Corn”
e0“cob deformity and reductions in yield tended to increase with glyphosate dose”
Claim · model-written summary
Yield reductions tended to increase with glyphosate dose.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- glyphosate dosee0
- Outcome
- reductions in yielde0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Corn”
e0“cob deformity and reductions in yield tended to increase with glyphosate dose”
Claim · model-written summary
In one environment group, 8-leaf corn treated with 7200 g·ae·ha-1 had a 9.5% yield reduction.
- Taxon
- cornZea mays subsp. mayse0
- Organ / stage
- 8- and 10-leaf stagee0
- Treatment
- 7200 g·ae·ha-1e0
- Outcome
- yielde0
- Direction
- reductione0
- Value
- 9.5%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn treated with 7200 g·ae·ha-1 at the 8- and 10-leaf stage had a 9.5% and 14.6% reduction in yield, respectively”
Claim · model-written summary
In one environment group, 10-leaf corn treated with 7200 g·ae·ha-1 had a 14.6% yield reduction.
- Taxon
- cornZea mays subsp. mayse0
- Organ / stage
- 8- and 10-leaf stagee0
- Treatment
- 7200 g·ae·ha-1e0
- Outcome
- yielde0
- Direction
- reductione0
- Value
- 14.6%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn treated with 7200 g·ae·ha-1 at the 8- and 10-leaf stage had a 9.5% and 14.6% reduction in yield, respectively”
Claim · model-written summary
In another environment group, corn yields resembled untreated controls across dose and timing.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- glyphosatee0
- Outcome
- corn yieldse0
- Direction
- similare0
- Comparator
- untreated controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn yields were similar to the untreated control regardless of glyphosate dose or timing”
The same questions in other papers
glyphosate · yield · Zea mays (maize)Results differ
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