Abstract
Winter oilseed cash cover crops are gaining popularity in integrated weed management programs for suppressing weeds. A study was conducted at two field sites (Fargo, North Dakota, and Morris, Minnesota) to determine the freezing tolerance and weed-suppressing traits of winter canola/rapeseed (Brassica napus L.) and winter camelina [Camelina sativa (L.) Crantz] in the Upper Midwestern USA. The top 10 freezing tolerant accessions from a phenotyped population of winter canola/rapeseed were bulked and planted at both locations along with winter camelina (cv. Joelle) as a check. To phenotype our entire winter B. napus population (621 accessions) for freezing tolerance, seeds were also bulked and planted at both locations. All B. napus and camelina were no-till seeded at Fargo and Morris at two planting dates, late August (PD1) and mid-September (PD2) 2019. Data for winter survival of oilseed crops (plants m−2) and their corresponding weed suppression (plants m−2 and dry matter m−2) were collected on two sampling dates (SD) in May and June 2020. Crop and SD were significant (p < 0.05) for crop plant density at both locations, and PD in Fargo and crop x PD interaction in Morris were significant for weed dry matter. At Morris and Fargo, PD1 produced greater winter B. napus survival (28% and 5%, respectively) and PD2 produced higher camelina survival (79% and 72%, respectively). Based on coefficient of determination (r2), ~50% of weed density was explained by camelina density, whereas ≤20% was explained by B. napus density at both locations. Camelina from PD2 suppressed weed dry matter by >90% of fallow at both locations, whereas weed dry matter in B. napus was not significantly different from fallow at either PD. Genotyping of overwintering canola/rapeseed under field conditions identified nine accessions that survived at both locations, which also had excellent freezing tolerance under controlled conditions. These accessions are good candidates for improving freezing tolerance in commercial canola cultivars.
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Claims 14
Claim · model-written summary
Crop and sampling date significantly affected crop plant density at both locations.
CamelinaNot reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Crop and SD were significant (p < 0.05) for crop plant density at both locations”
t0“Camelina and Canola/Rapeseed”
Claim · model-written summary
Planting date significantly affected weed dry matter at Fargo.
Not reportedDirection
Verbatim
e0“PD in Fargo and crop x PD interaction in Morris were significant for weed dry matter”
t0“Camelina and Canola/Rapeseed”
Claim · model-written summary
Crop by planting-date interaction significantly affected weed dry matter at Morris.
- Taxon
- Camelina and Canola/Rapeseedt0
- Treatment
- crop x PD interactione0
- Outcome
- weed dry mattere0
- Setting
- Morrise0
Not reportedDirection
Verbatim
e0“crop x PD interaction in Morris were significant for weed dry matter”
t0“Camelina and Canola/Rapeseed”
Claim · model-written summary
Early planting gave greater winter B. napus survival at Morris, at 28%.
- Taxon
- B. napus
_Brassica_napus_-_Habit.jpg?width=60)
Brassica napuse0 - Treatment
- PD1e0
- Outcome
- winter B. napus survivale0
- Direction
- greatere0
- Value
- 28%e0
- Comparator
- PD2e1
- Setting
- Morrise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)
Verbatim
e0“At Morris and Fargo, PD1 produced greater winter B. napus survival (28% and 5%, respectively)”
e1“PD2 produced higher camelina survival (79% and 72%, respectively)”
Claim · model-written summary
Early planting gave greater winter B. napus survival at Fargo, at 5%.
- Taxon
- B. napusBrassica napuse0
- Treatment
- PD1e0
- Outcome
- winter B. napus survivale0
- Direction
- greatere0
- Value
- 5%e0
- Comparator
- PD2e1
- Setting
- Fargoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At Morris and Fargo, PD1 produced greater winter B. napus survival (28% and 5%, respectively)”
e1“PD2 produced higher camelina survival (79% and 72%, respectively)”
Claim · model-written summary
Later planting gave higher camelina survival at Morris, at 79%.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PD2 produced higher camelina survival (79% and 72%, respectively)”
t0“At Morris and Fargo, PD1 produced greater winter B. napus survival (28% and 5%, respectively)”
e1“At Morris and Fargo, PD1 produced greater winter B. napus survival (28% and 5%, respectively)”
Claim · model-written summary
Later planting gave higher camelina survival at Fargo, at 72%.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PD2 produced higher camelina survival (79% and 72%, respectively)”
t0“At Morris and Fargo, PD1 produced greater winter B. napus survival (28% and 5%, respectively)”
e1“At Morris and Fargo, PD1 produced greater winter B. napus survival (28% and 5%, respectively)”
Claim · model-written summary
Camelina density explained about half the variation in weed density.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“~50% of weed density was explained by camelina density”
Claim · model-written summary
B. napus density explained no more than 20% of weed density variation.
- Taxon
- B. napusBrassica napuse0
- Treatment
- B. napus densitye0
- Outcome
- weed densitye0
- Value
- ≤20%e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“~50% of weed density was explained by camelina density, whereas ≤20% was explained by B. napus density at both locations”
Claim · model-written summary
Later-planted camelina suppressed weed dry matter by more than 90% relative to fallow.
- Treatment
- PD2e0
- Outcome
- weed dry mattere0
- Direction
- suppressede0
- Value
- >90%e0
- Comparator
- fallowe0
- Setting
- both locationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Camelina from PD2 suppressed weed dry matter by >90% of fallow at both locations”
Claim · model-written summary
Weed dry matter in B. napus did not differ significantly from fallow under either planting date.
- Taxon
- B. napusBrassica napuse0
- Treatment
- B. napuse0
- Outcome
- weed dry mattere0
- Direction
- not significantly differente0
- Qualifier
- either PDe0
- Comparator
- fallowe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“weed dry matter in B. napus was not significantly different from fallow at either PD”
Claim · model-written summary
Nine canola accessions survived at both field locations.
Verbatim
e0“identified nine accessions that survived at both locations”
t0“Canola/Rapeseed”
Claim · model-written summary
Those nine canola accessions also had excellent freezing tolerance in controlled conditions.
Verbatim
e0“which also had excellent freezing tolerance under controlled conditions”
t0“Canola/Rapeseed”
Claim · model-written summary
The surviving accessions are candidates for improving freezing tolerance in commercial canola.
- Taxon
- canola
.jpg?width=60)
Brassica napus var. napuse0 - Outcome
- good candidates for improving freezing tolerance in commercial canola cultivarse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“These accessions are good candidates for improving freezing tolerance in commercial canola cultivars.”