Abstract
Rice production by smallholder farmers in the savannas of Nigeria is constrained by weed competition. A field study was conducted to assess the effect of weed competition on the performance of upland rice varieties in 2005 and 2006 in the northern Guinea and Sudan savannas of Nigeria. The experiment was set up as a split plot in randomized complete block design. One hoe weeding at 3 weeks and two hoe-weeding regimes at 3 and 6 weeks after planting and a weedy plot were the main plot treatments. Five rice varieties CG14 (Oryza glaberima), WAB56-104 (O. sativa, tropical japonica, type), NERICA1, NERICA2 and NERICA4 (New Rice for Africa) constituted the subplot treatments. In the weedy plot, grain yield did not differ significantly between varieties. Grain yield in all varieties was significantly depressed by over 86% in the weedy plot compared with plots that were hoe-weeded once or twice. Grain yield, number of spikelets plant-1 and days to flowering, differed substantially in plots that were hoe-weeded once or twice. Across locations and varieties, grain yield were 4.8 and 6.7 times higher in plots weeded once or twice, respectively than in the weedy plots. Weed biomass was negatively correlated with grain yield (r=-0.70; P=<.0001), number of spikelets plant-1 (r=-0.40;; P=0.0060) and plant height (r=-0.41; P=0.0049). Averaged over locations, NERICA 4 produced grain yield that was significantly higher than other varieties. Our result suggests that two hoe-weedings are needed for optimum grain yield of the rice varieties.
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Claims 10
Claim · model-written summary
In the weedy plot, grain yield did not differ significantly between rice varieties.
- Taxon
- upland rice
Oryza sativat0 - Treatment
- weedy plote1
- Outcome
- grain yielde1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“upland rice”
e1“In the weedy plot, grain yield did not differ significantly between varieties”
Claim · model-written summary
Grain yield in all rice varieties was significantly depressed by over 86% in the weedy plot compared with plots hoe-weeded once or twice.
- Taxon
- upland riceOryza sativat0
- Treatment
- weedy plote1
- Outcome
- Grain yielde1
- Direction
- depressede1
- Value
- over 86%e1
- Comparator
- plots that were hoe-weeded once or twicee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“upland rice”
e1“Grain yield in all varieties was significantly depressed by over 86% in the weedy plot compared with plots that were hoe-weeded once or twice”
Claim · model-written summary
Grain yield, number of spikelets per plant and days to flowering differed substantially in plots hoe-weeded once or twice.
- Taxon
- upland riceOryza sativat0
- Treatment
- hoe-weeded once or twicee1
- Outcome
- Grain yield, number of spikelets plant-1 and days to floweringe1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“upland rice”
e1“Grain yield, number of spikelets plant-1 and days to flowering, differed substantially in plots that were hoe-weeded once or twice”
Claim · model-written summary
Across locations and varieties, grain yield was 4.8 times higher in plots weeded once than in weedy plots.
- Taxon
- upland riceOryza sativat0
- Treatment
- weeded once or twicee1
- Outcome
- grain yielde1
- Direction
- highere1
- Value
- 4.8e1
- Qualifier
- respectivelye1
- Comparator
- weedy plotse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“upland rice”
e1“grain yield were 4.8 and 6.7 times higher in plots weeded once or twice, respectively than in the weedy plots”
Claim · model-written summary
Across locations and varieties, grain yield was 6.7 times higher in plots weeded twice than in weedy plots.
- Taxon
- upland riceOryza sativat0
- Treatment
- weeded once or twicee1
- Outcome
- grain yielde1
- Direction
- highere1
- Value
- 6.7 timese1
- Qualifier
- respectivelye1
- Comparator
- weedy plotse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“upland rice”
e1“grain yield were 4.8 and 6.7 times higher in plots weeded once or twice, respectively than in the weedy plots”
Claim · model-written summary
Weed biomass was negatively correlated with grain yield (r=-0.70, P<0.0001) in upland rice.
- Taxon
- upland riceOryza sativat0
- Interactor
- Weede1weed
- Outcome
- grain yielde1
- Direction
- negatively correlatede1
- Value
- r=-0.70e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“upland rice”
e1“Weed biomass was negatively correlated with grain yield (r=-0.70; P=<.0001), number of spikelets plant-1 (r=-0.40;; P=0.0060) and plant height (r=-0.41; P=0.0049)”
Claim · model-written summary
Weed biomass was negatively correlated with number of spikelets per plant (r=-0.40, P=0.0060) in upland rice.
- Taxon
- upland riceOryza sativat0
- Interactor
- Weede1weed
- Outcome
- number of spikelets plant-1e1
- Direction
- negatively correlatede1
- Value
- r=-0.40e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“upland rice”
e1“Weed biomass was negatively correlated with grain yield (r=-0.70; P=<.0001), number of spikelets plant-1 (r=-0.40;; P=0.0060) and plant height (r=-0.41; P=0.0049)”
Claim · model-written summary
Weed biomass was negatively correlated with plant height (r=-0.41, P=0.0049) in upland rice.
- Taxon
- upland riceOryza sativat0
- Interactor
- Weede1weed
- Outcome
- plant heighte1
- Direction
- negatively correlatede1
- Value
- r=-0.41e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“upland rice”
e1“Weed biomass was negatively correlated with grain yield (r=-0.70; P=<.0001), number of spikelets plant-1 (r=-0.40;; P=0.0060) and plant height (r=-0.41; P=0.0049)”
Claim · model-written summary
Averaged over locations, NERICA 4 produced significantly higher grain yield than the other rice varieties.
- Taxon
- upland riceOryza sativat0
- Material
- NERICA 4e1
- Outcome
- grain yielde1
- Direction
- highere1
- Comparator
- other varietiese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“upland rice”
e1“NERICA 4 produced grain yield that was significantly higher than other varieties”
Claim · model-written summary
The authors recommend two hoe-weedings for optimum grain yield of the upland rice varieties.
- Taxon
- riceOryza sativae1
- Treatment
- two hoe-weedingse1
- Outcome
- optimum grain yielde1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Our result suggests that two hoe-weedings are needed for optimum grain yield of the rice varieties”