Abstract
This study aimed to investigate the possible causes for inconsistent performances of upland New Rice for Africa (NERICA) varieties in uplands and lowlands, while identifying important determinants in grain yield under deficient soil moisture. We compared the growth and yield of NERICA 1 and NERICA 5 to those of Yumenohatamochi, a Japanese upland variety, and Hinohikari, a Japanese lowland variety, subjected to different water management regimes (continually flooded, supplementary irrigation, and non-irrigation). Under conditions of deficient soil moisture, panicle number per square meter, spikelet number per panicle, and 1000-grain weight of NERICAs decreased, whereas the panicle number of the Japanese varieties experienced little change. In contrast, the grain filling ratio was unaffected by water management, irrespective of variety. The primary source of yield reduction under low soil water conditions was a decrease in spikelet number per panicle, and water stress intensity was the primary factor for the degree of this reduction. Variation in the abortion of secondary rachis-branches caused differences between NERICAs in their spikelet number response to soil moisture deficiency. The inconsistency in NERICA performance across uplands vs. lowlands can be partially attributed to variation in yield response to low soil water conditions. Moreover, water stress intensity and the presence of a water gradient along the vertical soil profile may combine to affect the fluctuation in NERICA performance under upland conditions.
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Claims 8
Claim · model-written summary
Deficient soil moisture decreased NERICA panicle number, spikelet number and 1000-grain weight.
- Taxon
- NERICAst0
- Treatment
- deficient soil moisturee0
- Outcome
- panicle number per square meter, spikelet number per panicle, and 1000-grain weighte0
- Direction
- decreasede0
Not reportedComparator
Verbatim
e0“Under conditions of deficient soil moisture, panicle number per square meter, spikelet number per panicle, and 1000-grain weight of NERICAs decreased”
t0“upland NERICAs”
Claim · model-written summary
Japanese varieties showed little change in panicle number under deficient moisture.
- Taxon
- Rice
Oryza sativae2 - Material
- Japanese varietiese0
- Treatment
- deficient soil moisturee0
- Outcome
- panicle numbere0
- Direction
- little changee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under conditions of deficient soil moisture, panicle number per square meter, spikelet number per panicle, and 1000-grain weight of NERICAs decreased, whereas the panicle number of the Japanese varieties experienced little change.”
e1“Yumenohatamochi, a Japanese upland variety, and Hinohikari, a Japanese lowland variety”
e2“upland New Rice for Africa (NERICA) varieties”
Claim · model-written summary
Water management did not affect grain filling ratio regardless of variety.
- Taxon
- RiceOryza sativae1
- Treatment
- water managemente0
- Outcome
- grain filling ratioe0
- Direction
- unaffectede0
- Qualifier
- irrespective of varietye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the grain filling ratio was unaffected by water management, irrespective of variety.”
e1“upland New Rice for Africa (NERICA) varieties”
Claim · model-written summary
Decreased spikelet number per panicle was the primary source of yield reduction under low soil water.
Verbatim
e0“The primary source of yield reduction under low soil water conditions was a decrease in spikelet number per panicle”
t0“upland NERICAs”
Claim · model-written summary
Water stress intensity was the primary determinant of spikelet-number reduction.
Not reportedDirection
Verbatim
e0“The primary source of yield reduction under low soil water conditions was a decrease in spikelet number per panicle, and water stress intensity was the primary factor for the degree of this reduction.”
t0“upland NERICAs”
Claim · model-written summary
Secondary rachis-branch abortion variation caused NERICA differences in spikelet response to moisture deficiency.
Verbatim
e0“Variation in the abortion of secondary rachis-branches caused differences between NERICAs in their spikelet number response to soil moisture deficiency.”
Claim · model-written summary
Variable yield response to low soil water partially explains inconsistent upland versus lowland performance.
Verbatim
e0“The inconsistency in NERICA performance across uplands vs. lowlands can be partially attributed to variation in yield response to low soil water conditions.”
Claim · model-written summary
Stress intensity and vertical soil water gradients may jointly affect upland NERICA performance fluctuations.
Verbatim
e0“water stress intensity and the presence of a water gradient along the vertical soil profile may combine to affect the fluctuation in NERICA performance under upland conditions.”
The same questions in other papers
soil water · yield · Oryza sativa (rice)Positive and negative results
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