Abstract
Abstract Orchardgrass ( Dactylis glomerata L.) is an important forage seed crop, but unlike other cool‐season grasses, seed yields have not increased over time. Seed yield increases in orchardgrass may be possible with plant growth regulators (PGRs) such as trinexapac‐ethyl (TE) and chlormequat chloride (CCC). Field trials were conducted at Hyslop Experimental Farm near Corvallis, Oregon, over three crop years (2017–2019) to examine the effects of spring nitrogen (N) and PGRs on seed production characteristics in orchardgrass. Spring N treatments included 0, 112, 157, and 202 kg N ha −1 and PGR applications were timed using the BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie) scale. Four PGR treatments included an untreated control, 210 g TE ha −1 at BBCH 32, 210 g TE ha −1 at BBCH 51, and 105 g TE ha −1 + 1500 g CCC ha −1 at BBCH 32. An interaction of spring N and PGR increased seed yields in 2 years, while spring N and PGR increased seed yield independently in the other year. The combination of TE and CCC PGRs did not increase seed yield over TE alone. Seed yield increases from spring N were due to an increase in seed number m −2 , while increases in seed yield attributable to PGRs were the result of increased seed number m −2 and harvest index. This study suggests that the combination of 112 kg ha −1 spring N and 210 g ha −1 TE PGR is the best practice to maximize seed yield in orchardgrass.
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Claims 8
Claim · model-written summary
Spring nitrogen and PGRs interacted to increase seed yield in two years.
- Taxon
- orchardgrass
.jpg?width=60)
Dactylis glomeratat0 - Treatment
- spring N and PGRe0
- Outcome
- seed yieldse0
- Direction
- increasede0
- Value
- 2 yearse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“An interaction of spring N and PGR increased seed yields in 2 years”
t0“orchardgrass”
Claim · model-written summary
Spring nitrogen independently increased seed yield in the other year.
- Taxon
- orchardgrassDactylis glomeratat0
- Treatment
- spring Ne0
- Outcome
- seed yielde0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“while spring N and PGR increased seed yield independently in the other year.”
t0“orchardgrass”
Claim · model-written summary
PGRs independently increased seed yield in the other year.
- Taxon
- orchardgrassDactylis glomeratat0
- Treatment
- PGRe0
- Outcome
- seed yielde0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“while spring N and PGR increased seed yield independently in the other year.”
t0“orchardgrass”
Claim · model-written summary
Combined TE and CCC did not increase seed yield over TE alone.
- Taxon
- orchardgrassDactylis glomeratat0
- Treatment
- combination of TE and CCC PGRse0
- Outcome
- seed yielde0
- Direction
- did not increasee0
- Comparator
- TE alonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The combination of TE and CCC PGRs did not increase seed yield over TE alone.”
t0“orchardgrass”
Claim · model-written summary
Spring nitrogen increased seed number per square meter, accounting for seed-yield gains.
- Taxon
- orchardgrassDactylis glomeratat0
- Treatment
- spring Ne0
- Outcome
- seed number m −2e0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seed yield increases from spring N were due to an increase in seed number m −2”
t0“orchardgrass”
Claim · model-written summary
PGRs increased seed number per square meter, contributing to seed-yield gains.
- Taxon
- orchardgrassDactylis glomeratat0
- Treatment
- PGRse0
- Outcome
- seed number m −2e0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increases in seed yield attributable to PGRs were the result of increased seed number m −2 and harvest index.”
t0“orchardgrass”
Claim · model-written summary
PGRs increased harvest index, contributing to seed-yield gains.
- Taxon
- orchardgrassDactylis glomeratat0
- Treatment
- PGRse0
- Outcome
- harvest indexe0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increases in seed yield attributable to PGRs were the result of increased seed number m −2 and harvest index.”
t0“orchardgrass”
Claim · model-written summary
The authors recommend 112 kg ha −1 spring N with 210 g ha −1 TE to maximize orchardgrass seed yield.
- Taxon
- orchardgrassDactylis glomeratae0
- Treatment
- 112 kg ha −1 spring N and 210 g ha −1 TE PGRe0
- Outcome
- best practice to maximize seed yielde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the combination of 112 kg ha −1 spring N and 210 g ha −1 TE PGR is the best practice to maximize seed yield in orchardgrass.”
The same questions in other papers
trinexapac-ethyl · yield · Dactylis glomerata (cocksfoot)Positive and negative results
2 reporting no difference from an alternative
- positive
- positive
chlormequat chloride · yield · Dactylis glomerata (cocksfoot)Positive and negative results
2 reporting no difference from an alternative
- positive
- positive
class · yield · Dactylis glomerata (cocksfoot)Results agree
1 paper in the same direction as this paper
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.