Abstract
Resistance to herbicides in the most important weeds threatens the sustainability of California rice. Weed-competitive rice cultivars could be a low-cost and safe nonchemical addition to an integrated weed management program. Trade-offs between competitiveness and productivity and inconsistent trait expression under weedy and weed-free conditions could complicate the breeding of competitive rice cultivars. A 2-year competition experiment was conducted in the greenhouse involving eight rice cultivars and two weed competition regimes (presence or absence of late watergrass) to examine the effects of rice weed-suppressive ability and tolerance to weed competition (weed tolerance) on rice yield. Competition reduced average rice yield from 32 to 48%, and watergrass biomass from 44 to 77%. Path analysis suggested that enhancing rice weed-suppressive ability and weed tolerance while minimizing possible productivity trade-offs should promote early (12 d after seeding) growth and light-capture traits followed by moderate growth rates before heading and a vigorous grain filling period. Crop growth rate (CGR) after heading was a relevant determinant of yield (direct path: 0.82, P < 0.01) and correlated (r = 0.30, P < 0.01) with weed tolerance. Late biomass accumulation was negatively correlated with harvest index and CGR during ripening (r = −0.46, P < 0.01); thus, late-season competitiveness can lower productivity. Rice traits conferring competitiveness were correlated across weed competition regimes (r = 0.36–0.81, P < 0.01). However, significant cultivar-by-competition and cultivar-by-year interactions suggest that selection efficiency would be greater when traits are identified under competition and in different environments. This study relates to the phenotypic expression of traits for competitiveness. Breeding competitive cultivars will require additional knowledge on trait heritability, genetic correlations with competitiveness, and on the effects of the environment upon gene expression.
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Claims 10
Claim · model-written summary
Weed competition reduced average rice yield from 32 to 48% in a greenhouse experiment compared with absence of late watergrass.
- Taxon
- rice
Oryza sativae0 - Treatment
- weed competitione1
- Interactor
- late watergrasse1weed
- Outcome
- rice yielde0
- Direction
- reducede0
- Value
- 32 to 48%e0
- Comparator
- absence of late watergrasse1
- Setting
- greenhousee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Competition reduced average rice yield from 32 to 48%”
e1“two weed competition regimes (presence or absence of late watergrass)”
e2“A 2-year competition experiment was conducted in the greenhouse”
Claim · model-written summary
Weed competition reduced late watergrass biomass from 44 to 77%.
- Taxon
- riceOryza sativae0
- Treatment
- weed competitione1
- Interactor
- watergrasse0weed
- Outcome
- watergrass biomasse0
- Direction
- reducede0
- Value
- 44 to 77%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Competition reduced average rice yield from 32 to 48%, and watergrass biomass from 44 to 77%”
e1“two weed competition regimes (presence or absence of late watergrass)”
Claim · model-written summary
Enhancing rice weed-suppressive ability and weed tolerance should promote early growth and light-capture traits.
- Taxon
- riceOryza sativae3
- Outcome
- early (12 d after seeding) growth and light-capture traitse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Path analysis suggested that enhancing rice weed-suppressive ability and weed tolerance while minimizing possible productivity trade-offs should promote early (12 d after seeding) growth and light-capture traits followed by moderate growth rates before heading and a vigorous grain filling period”
Claim · model-written summary
Crop growth rate after heading is a determinant of rice yield (direct path 0.82).
- Taxon
- riceOryza sativae0
- Organ / stage
- after headinge4
- Outcome
- yielde4
- Direction
- increaseinferrede4
- Value
- 0.82e4
- Qualifier
- P < 0.01e4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Competition reduced average rice yield from 32 to 48%, and watergrass biomass from 44 to 77%”
e4“Crop growth rate (CGR) after heading was a relevant determinant of yield (direct path: 0.82, P < 0.01)”
Claim · model-written summary
Crop growth rate after heading is correlated with weed tolerance (r = 0.30).
- Taxon
- riceOryza sativae0
- Organ / stage
- after headinge5
- Outcome
- weed tolerancee5
- Direction
- increaseinferrede5
- Value
- r = 0.30e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Competition reduced average rice yield from 32 to 48%, and watergrass biomass from 44 to 77%”
e5“Crop growth rate (CGR) after heading was a relevant determinant of yield (direct path: 0.82, P < 0.01) and correlated (r = 0.30, P < 0.01) with weed tolerance”
Claim · model-written summary
Late biomass accumulation is negatively correlated with harvest index (r = −0.46).
- Taxon
- riceOryza sativae0
- Treatment
- Late biomass accumulatione6
- Outcome
- harvest indexe6
- Direction
- negativelye6
- Value
- r = −0.46e6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Competition reduced average rice yield from 32 to 48%, and watergrass biomass from 44 to 77%”
e6“Late biomass accumulation was negatively correlated with harvest index and CGR during ripening (r = −0.46, P < 0.01)”
Claim · model-written summary
Late biomass accumulation is negatively correlated with CGR during ripening (r = −0.46).
- Taxon
- riceOryza sativae0
- Treatment
- Late biomass accumulatione6
- Outcome
- CGR during ripeninge6
- Direction
- negativelye6
- Value
- r = −0.46e6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Competition reduced average rice yield from 32 to 48%, and watergrass biomass from 44 to 77%”
e6“Late biomass accumulation was negatively correlated with harvest index and CGR during ripening (r = −0.46, P < 0.01)”
Claim · model-written summary
Rice traits conferring competitiveness are positively correlated across weed competition regimes (r = 0.36–0.81).
- Taxon
- riceOryza sativae0
- Treatment
- weed competition regimese7
- Outcome
- traits conferring competitivenesse7
- Direction
- increaseinferrede7
- Value
- r = 0.36–0.81e7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Competition reduced average rice yield from 32 to 48%, and watergrass biomass from 44 to 77%”
e7“Rice traits conferring competitiveness were correlated across weed competition regimes (r = 0.36–0.81, P < 0.01)”
Claim · model-written summary
Cultivar-by-competition and cultivar-by-year interactions are significant for rice.
- Taxon
- riceOryza sativae0
- Outcome
- cultivar-by-competition and cultivar-by-year interactionse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Competition reduced average rice yield from 32 to 48%, and watergrass biomass from 44 to 77%”
e7“However, significant cultivar-by-competition and cultivar-by-year interactions suggest that selection efficiency would be greater when traits are identified under competition and in different environments”
Claim · model-written summary
Selection efficiency for competitive traits would be greater when traits are identified under competition and in different environments.
- Taxon
- riceOryza sativae0
- Outcome
- selection efficiencye7
- Qualifier
- traits are identified under competition and in different environmentse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Competition reduced average rice yield from 32 to 48%, and watergrass biomass from 44 to 77%”
e7“However, significant cultivar-by-competition and cultivar-by-year interactions suggest that selection efficiency would be greater when traits are identified under competition and in different environments”
The same questions in other papers
competition · yield · Oryza sativa (rice)Results differ
42 papers in the same direction as this paper · 4 in the opposite direction
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