Abstract
Poor crop establishment, high weed infestation, and consequent yield loss are major concerns for dry-seeded rice (DSR). Flooding after seeding helps in managing weeds but reduces seed germination and crop stand. Anaerobic germination (AG) tolerant genotypes could overcome these problems in DSR. Screenhouse experiments were established to evaluate the effect of seed sowing depth (SD) (0.5 cm, 1 cm, and 2 cm) and flooding depth (FD) (saturated, 2 cm, and 5 cm) on crop establishment, early growth, and weed competitiveness in DSR using AG-tolerant genotypes (Khao Hlan On, Ma-Zhan Red, IR64+AG1, and IR64). Echinochloa crus-galli, Ludwigia hyssopifolia, and Cyperus difformis were used in the weedy plots. Rice plants reached maximum emergence 9-13 days later under flooding compared with saturated conditions. Crop emergence decreased by 12-22% at 0.5 and 1 cm SD and by 48-60% at 2 cm SD, when combined with 2 or 5 cm FD compared with saturated conditions. The 2 cm SD reduced seedling emergence by 23-42% in Khao Hlan On and Ma-Zhan Red, by 62-70% in IR64+AG1, and by 90-92% in IR64 under flooding. Initial growth in rice plant height was slow under flooding but increased progressively after the seedlings emerged from water and the final height was not affected by FD. Leaf area, total shoot biomass, tiller density, and leaf number per pot of rice were higher at 1 cm SD (P<0.05), but decreased drastically at 2 cm SD under flooding. The emergence of E. crus-galli and L. hyssopifolia decreased by 53-65% and 89-95%, respectively, but increased by 49-68% in C. difformis under 2 and 5 cm FD, respectively, compared with saturated conditions. The shoot biomass of the weeds followed the same trend. Khao Hlan On showed the highest weed-competitive ability under all FD while the biomass of IR64+AG1 and IR64 decreased by 10-14% due to weed competition under 2 cm FD. The 1 cm SD showed better growth for all genotypes under different FD. The 2 cm FD is sufficient to have a significant control of problematic weed species. The tolerance of AG of rice genotypes should be further enhanced to increase their weed-competitive ability.
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Claims 20
Claim · model-written summary
Flooding delayed maximum rice emergence by 9–13 days versus saturation.
- Taxon
- Rice
Oryza sativae0 - Treatment
- floodinge0
- Outcome
- maximum emergencee0
- Direction
- latere0
- Value
- 9-13 dayse0
- Comparator
- saturated conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rice plants reached maximum emergence 9-13 days later under flooding compared with saturated conditions.”
Claim · model-written summary
Flooding at 0.5 and 1 cm sowing depths reduced crop emergence by 12–22%.
- Taxon
- RiceOryza sativat0
- Treatment
- 0.5 and 1 cm SDe0
- Outcome
- Crop emergencee0
- Direction
- decreasede0
- Value
- 12-22%e0
- Qualifier
- 2 or 5 cm FDe0
- Comparator
- saturated conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Crop emergence decreased by 12-22% at 0.5 and 1 cm SD and by 48-60% at 2 cm SD, when combined with 2 or 5 cm FD compared with saturated conditions.”
t0“Rice”
Claim · model-written summary
Flooding at 2 cm sowing depth reduced crop emergence by 48–60%.
- Taxon
- RiceOryza sativat0
- Treatment
- 2 cm SDe0
- Outcome
- Crop emergencee0
- Direction
- decreasede0
- Value
- 48-60%e0
- Qualifier
- 2 or 5 cm FDe0
- Comparator
- saturated conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Crop emergence decreased by 12-22% at 0.5 and 1 cm SD and by 48-60% at 2 cm SD, when combined with 2 or 5 cm FD compared with saturated conditions.”
t0“Rice”
Claim · model-written summary
Two-centimeter sowing depth reduced seedling emergence by 23–42% in Khao Hlan On.
- Taxon
- RiceOryza sativat0
- Material
- Khao Hlan One0
- Treatment
- 2 cm SDe0
- Outcome
- seedling emergencee0
- Direction
- reducede0
- Value
- 23-42%e0
- Qualifier
- under floodinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The 2 cm SD reduced seedling emergence by 23-42% in Khao Hlan On and Ma-Zhan Red, by 62-70% in IR64+AG1, and by 90-92% in IR64 under flooding.”
t0“Rice”
Claim · model-written summary
Two-centimeter sowing depth reduced seedling emergence by 23–42% in Ma-Zhan Red.
- Taxon
- RiceOryza sativat0
- Material
- Ma-Zhan Rede0
- Treatment
- 2 cm SDe0
- Outcome
- seedling emergencee0
- Direction
- reducede0
- Value
- 23-42%e0
- Qualifier
- under floodinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The 2 cm SD reduced seedling emergence by 23-42% in Khao Hlan On and Ma-Zhan Red, by 62-70% in IR64+AG1, and by 90-92% in IR64 under flooding.”
t0“Rice”
Claim · model-written summary
Two-centimeter sowing depth reduced seedling emergence by 62–70% in IR64+AG1.
- Taxon
- RiceOryza sativat0
- Material
- IR64+AG1e0
- Treatment
- 2 cm SDe0
- Outcome
- seedling emergencee0
- Direction
- reducede0
- Value
- 62-70%e0
- Qualifier
- under floodinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The 2 cm SD reduced seedling emergence by 23-42% in Khao Hlan On and Ma-Zhan Red, by 62-70% in IR64+AG1, and by 90-92% in IR64 under flooding.”
t0“Rice”
Claim · model-written summary
Two-centimeter sowing depth reduced seedling emergence by 90–92% in IR64.
- Taxon
- RiceOryza sativat0
- Material
- IR64e0
- Treatment
- 2 cm SDe0
- Outcome
- seedling emergencee0
- Direction
- reducede0
- Value
- 90-92%e0
- Qualifier
- under floodinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The 2 cm SD reduced seedling emergence by 23-42% in Khao Hlan On and Ma-Zhan Red, by 62-70% in IR64+AG1, and by 90-92% in IR64 under flooding.”
t0“Rice”
Claim · model-written summary
Rice height growth was initially slow under flooding but increased after emergence from water.
- Taxon
- riceOryza sativae0
- Treatment
- floodinge0
- Outcome
- growth in rice plant heighte0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Initial growth in rice plant height was slow under flooding but increased progressively after the seedlings emerged from water”
Claim · model-written summary
Final rice height was unaffected by flooding depth.
- Taxon
- RiceOryza sativat0
- Treatment
- FDe0
- Outcome
- final heighte0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the final height was not affected by FD.”
t0“Rice”
Claim · model-written summary
At 1 cm sowing depth, rice leaf area, shoot biomass, tiller density and leaf number were higher.
- Taxon
- riceOryza sativae0
- Treatment
- 1 cm SDe0
- Outcome
- Leaf area, total shoot biomass, tiller density, and leaf number per pote0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf area, total shoot biomass, tiller density, and leaf number per pot of rice were higher at 1 cm SD (P<0.05)”
Claim · model-written summary
Those rice growth traits decreased sharply at 2 cm sowing depth under flooding.
- Taxon
- riceOryza sativae0
- Treatment
- 2 cm SD under floodinge0
- Outcome
- Leaf area, total shoot biomass, tiller density, and leaf number per pote0
- Direction
- decreased drasticallye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf area, total shoot biomass, tiller density, and leaf number per pot of rice were higher at 1 cm SD (P<0.05), but decreased drastically at 2 cm SD under flooding.”
Claim · model-written summary
Flooding decreased Echinochloa crus-galli emergence by 53–65%.
- Taxon
- RiceOryza sativat0
- Treatment
- 2 and 5 cm FDe0
- Interactor
- E. crus-galli
Echinochloa crus-gallie0weed - Outcome
- emergence of E. crus-gallie0
- Direction
- decreasede0
- Value
- 53-65%e0
- Comparator
- saturated conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The emergence of E. crus-galli and L. hyssopifolia decreased by 53-65% and 89-95%, respectively, but increased by 49-68% in C. difformis under 2 and 5 cm FD, respectively, compared with saturated conditions.”
t0“Rice”
Claim · model-written summary
Flooding decreased Ludwigia hyssopifolia emergence by 89–95%.
- Taxon
- RiceOryza sativat0
- Treatment
- 2 and 5 cm FDe0
- Interactor
- L. hyssopifolia
Ludwigia hyssopifoliae0weed - Outcome
- L. hyssopifoliae0
- Direction
- decreasede0
- Value
- 89-95%e0
- Comparator
- saturated conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The emergence of E. crus-galli and L. hyssopifolia decreased by 53-65% and 89-95%, respectively, but increased by 49-68% in C. difformis under 2 and 5 cm FD, respectively, compared with saturated conditions.”
t0“Rice”
Claim · model-written summary
Flooding increased Cyperus difformis emergence by 49–68%.
- Taxon
- RiceOryza sativat0
- Treatment
- 2 and 5 cm FDe0
- Interactor
- C. difformis
Cyperus difformise0weed - Outcome
- C. difformise0
- Direction
- increasede0
- Value
- 49-68%e0
- Comparator
- saturated conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The emergence of E. crus-galli and L. hyssopifolia decreased by 53-65% and 89-95%, respectively, but increased by 49-68% in C. difformis under 2 and 5 cm FD, respectively, compared with saturated conditions.”
t0“Rice”
Claim · model-written summary
Weed shoot biomass followed the same flooding response as emergence.
- Taxon
- RiceOryza sativat0
- Interactor
- weedse0weed
- Outcome
- shoot biomass of the weedse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The shoot biomass of the weeds followed the same trend.”
t0“Rice”
Claim · model-written summary
Khao Hlan On had the highest weed competitive ability at all flooding depths.
- Taxon
- RiceOryza sativat0
- Material
- Khao Hlan One0
- Treatment
- all FDe0
- Outcome
- highest weed-competitive abilitye0
- Direction
- higheste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Khao Hlan On showed the highest weed-competitive ability under all FD”
t0“Rice”
Claim · model-written summary
Weed competition reduced IR64+AG1 biomass by 10–14% under 2 cm flooding.
- Taxon
- RiceOryza sativat0
- Material
- IR64+AG1e0
- Treatment
- weed competitione0
- Interactor
- weede0weed
- Outcome
- biomasse0
- Direction
- decreasede0
- Value
- 10-14%e0
- Qualifier
- 2 cm FDe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the biomass of IR64+AG1 and IR64 decreased by 10-14% due to weed competition under 2 cm FD.”
t0“Rice”
Claim · model-written summary
Weed competition reduced IR64 biomass by 10–14% under 2 cm flooding.
- Taxon
- RiceOryza sativat0
- Material
- IR64e0
- Treatment
- weed competitione0
- Interactor
- weede0weed
- Outcome
- biomasse0
- Direction
- decreasede0
- Value
- 10-14%e0
- Qualifier
- 2 cm FDe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the biomass of IR64+AG1 and IR64 decreased by 10-14% due to weed competition under 2 cm FD.”
t0“Rice”
Claim · model-written summary
One-centimeter sowing depth gave better growth for all rice genotypes at different flooding depths.
- Taxon
- RiceOryza sativat0
- Treatment
- 1 cm SDe0
- Outcome
- growthe0
- Direction
- bettere0
- Qualifier
- all genotypes under different FDe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The 1 cm SD showed better growth for all genotypes under different FD.”
t0“Rice”
Claim · model-written summary
The authors judged 2 cm flooding sufficient for significant control of problematic weeds.
- Taxon
- RiceOryza sativat0
- Interactor
- weede0weed
- Outcome
- 2 cm FD is sufficient to have a significant control of problematic weed speciese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The 2 cm FD is sufficient to have a significant control of problematic weed species.”
t0“Rice”
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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.