Abstract
The objective was to determine whether a relationship between nitrate reductase activity (NRA) and grain yields and grain protein could be detected for six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation. NRA was expressed as seasonal input of reduced N (kg N ha‐ 1 ) and as seasonal averages of activity (µmoles N, g fresh wt‐ 1 , hr‐ 1 ). The treatment variables were plant density (59,300 and 79,000 plants ha‐ 1 ) and tune of application (14 days after tassel initiation, at tassel emergence, and at silking) of nitrate‐N (337 kg N ha‐ 1 ). Each supplemental N treatment, regardless of time of application, significantly increased the percent of grain protein for all genotypes and amount of grain protein ha‐ 1 for all but one hybrid (No. 3). In contrast, the supplemental N treatments did not cause significant increases in grain yields within a given genotype. There were significant differences in grain yield and grain protein among the genotypes. The treatments increased leaf blade nitrate concentration which resulted in a corresponding increase in NRA. However, each successive N application was less effective in increasing and maintaining leaf nitrate content and enzyme activity. None of the hybrids were able to maintain a high concentration of leaf blade nitrate after silking, even though massive amounts of nitrate were applied to the soil. Compared to all other hybrids, hybrid No. 4 maintained a slightly higher level of nitrate concentration and enzyme activity in the leaves during the post‐anthesis stage. NRA of the total leaf canopy, expressed as seasonal averages or converted into seasonal input of reduced N, showed a significant positive correlation with grain protein (kg N/ha), grain yield, and total reduced N in the vegetative material (above ground) and grain and stover at maturity. The highest correlations between NRA and yields of grain and grain protein (kg N/ha) were obtained during the stages of ear initiation and development. This suggests that a minimal number (1 to 3) of samplings would be as effective as the laborious full season samplings (12 or more dates) in selecting individual plants or varieties that have a high potential for grain yields or grain protein production.
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Claims 11
Claim · model-written summary
Nitrate reductase activity of the total leaf canopy correlated positively with grain protein, grain yield and total reduced N in corn.
- Taxon
- corn
Zea mays subsp. mayse0 - Material
- six corn ( Zea mays L.) hybridse0
- Outcome
- grain protein (kg N/ha), grain yield, and total reduced Ne1
- Direction
- positivee1
- Setting
- field conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation”
e1“NRA of the total leaf canopy, expressed as seasonal averages or converted into seasonal input of reduced N, showed a significant positive correlation with grain protein (kg N/ha), grain yield, and total reduced N in the vegetative material (above ground) and grain and stover at maturity”
Claim · model-written summary
Supplemental N treatments significantly increased the percent of grain protein in all genotypes.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- supplemental N treatmente2
- Outcome
- percent of grain proteine2
- Direction
- significantly increasede2
- Qualifier
- regardless of time of applicatione2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation”
e2“Each supplemental N treatment, regardless of time of application, significantly increased the percent of grain protein for all genotypes”
Claim · model-written summary
Supplemental N treatments did not significantly increase grain yield within a given genotype.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- supplemental N treatmentse3
- Outcome
- grain yieldse3
- Direction
- did not cause significant increasese3
- Qualifier
- within a given genotypee3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation”
e3“In contrast, the supplemental N treatments did not cause significant increases in grain yields within a given genotype”
Claim · model-written summary
Grain yield and grain protein differed significantly among corn genotypes.
- Taxon
- cornZea mays subsp. mayse0
- Material
- genotypese4
- Outcome
- grain yield and grain proteine4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation”
e4“There were significant differences in grain yield and grain protein among the genotypes”
Claim · model-written summary
Treatments increased leaf blade nitrate concentration in corn.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- The treatmentse5
- Outcome
- leaf blade nitrate concentratione5
- Direction
- increasede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation”
e5“The treatments increased leaf blade nitrate concentration which resulted in a corresponding increase in NRA”
Claim · model-written summary
Treatments caused a corresponding increase in nitrate reductase activity in corn leaves.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- The treatmentse5
- Outcome
- NRAe5
- Direction
- corresponding increasee5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation”
e5“The treatments increased leaf blade nitrate concentration which resulted in a corresponding increase in NRA”
Claim · model-written summary
Each successive N application was less effective in increasing and maintaining leaf nitrate content and enzyme activity in corn.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- each successive N applicatione6
- Outcome
- leaf nitrate content and enzyme activitye6
- Direction
- less effectivee6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation”
e6“However, each successive N application was less effective in increasing and maintaining leaf nitrate content and enzyme activity”
Claim · model-written summary
None of the corn hybrids maintained a high leaf blade nitrate concentration after silking.
- Taxon
- cornZea mays subsp. mayse0
- Material
- hybridse7
- Outcome
- maintain a high concentration of leaf blade nitrate after silkinge7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation”
e7“None of the hybrids were able to maintain a high concentration of leaf blade nitrate after silking”
Claim · model-written summary
Hybrid No. 4 maintained a slightly higher leaf nitrate and enzyme activity level than all other hybrids during the post-anthesis stage.
- Taxon
- cornZea mays subsp. mayse0
- Material
- hybrid No. 4e1
- Outcome
- level of nitrate concentration and enzyme activitye1
- Direction
- slightly highere1
- Comparator
- all other hybridse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation”
e1“Compared to all other hybrids, hybrid No. 4 maintained a slightly higher level of nitrate concentration and enzyme activity in the leaves”
Claim · model-written summary
A minimal number (1 to 3) of samplings would be as effective as full season sampling in selecting corn plants or varieties with high grain yield or grain protein potential.
- Taxon
- cornZea mays subsp. mayse0
- Outcome
- minimal number (1 to 3) of samplingse1
- Qualifier
- in selecting individual plants or varietiese1
- Comparator
- full season samplings (12 or more dates)e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation”
e1“a minimal number (1 to 3) of samplings would be as effective as the laborious full season samplings (12 or more dates) in selecting individual plants or varieties”
Claim · model-written summary
The highest correlations between NRA and grain yield and grain protein in corn occurred during ear initiation and development.
- Taxon
- cornZea mays subsp. mayse0
- Organ / stage
- ear initiation and developmente1
- Outcome
- yields of grain and grain protein (kg N/ha)e1
- Direction
- higheste1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“six corn ( Zea mays L.) hybrids grown under field conditions with supplemental N and irrigation”
e1“The highest correlations between NRA and yields of grain and grain protein (kg N/ha) were obtained during the stages of ear initiation and development”
The same questions in other papers
nitrogen · quality: protein · Zea mays (maize)Positive and negative results
163 papers in the same direction as this paper · 14 in the opposite direction · 3 reporting no difference from an alternative
- no effect
- no effect
- negative
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See all 181 papers →nitrogen · yield · Zea mays (maize)Positive and negative results
278 papers in the same direction as this paper · 1,906 in the opposite direction
- positive
- positive
- positive
2,181 papers more in this group
See all 2,185 papers →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.