Abstract
Grain yield improvement of maize (Zea mays L.) hybrids has been associated with delayed leaf senescence. The objective of this study was to quantify the vertical profile of leaf senescence during the grain-filling period in an older hybrid (‘Pride 5’) and two more recent maize hybrids (‘Pioneer 3902’ and ‘Pioneer 3893’). Leaf senescence was rated visually from silking to maturity on each individual leaf across the vertical leaf-area profile along the stem of maize plants growing in the field at 1, 3.5, and 12 plants m−2 near Elora, ON, Canada, during the 1999 to 2001 growing seasons. Maximum leaf area index (LAI) at silking was greater in newer hybrids than in the older hybrid. Rate of leaf senescence across hybrids and plant population densities progressed at a linear rate of 0.44% d−1 during the first half of the grain-filling period, whereas the rate was 1.87% d−1 during the second half of the grain-filling period. Rates of leaf senescence were 3.4 and 2.1 times greater in the older hybrid than in the newer hybrids during the first and second half of the grain-filling period, respectively. During the first half of the grain-filling period, leaf senescence increased from the medium to the highest plant population density, whereas rates of senescence during the second half of the grain-filling period declined with an increase in plant population density for the older hybrid and rates were lowest at the medium plant population density for the newer hybrids. A top–bottom profile of leaf senescence was observed during the second half of the grain-filling period, with leaves in the central section of the canopy being the last leaves to senesce, and this phenomenon was more marked in the newer hybrids.
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Claims 9
Claim · model-written summary
Leaf senescence across hybrids and densities progressed at 0.44% d−1 during the first half of the grain-filling period.
- Organ / stage
- first half of the grain-filling periode1
- Outcome
- Rate of leaf senescencee1
- Value
- 0.44% d−1e1
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize (Zea mays L.)”
e1“Rate of leaf senescence across hybrids and plant population densities progressed at a linear rate of 0.44% d−1 during the first half of the grain-filling period, whereas the rate was 1.87% d−1 during the second half of the grain-filling period”
Claim · model-written summary
Leaf senescence across hybrids and densities progressed at 1.87% d−1 during the second half of the grain-filling period.
- Organ / stage
- second half of the grain-filling periode1
- Outcome
- Rate of leaf senescencee1
- Value
- 1.87% d−1e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize (Zea mays L.)”
e1“Rate of leaf senescence across hybrids and plant population densities progressed at a linear rate of 0.44% d−1 during the first half of the grain-filling period, whereas the rate was 1.87% d−1 during the second half of the grain-filling period”
Claim · model-written summary
The older hybrid had a leaf senescence rate 3.4 times greater than the newer hybrids in the first half of grain filling.
- Material
- older hybride2
- Outcome
- Rates of leaf senescencee2
- Direction
- greatere2
- Value
- 3.4e2
- Comparator
- newer hybridse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize (Zea mays L.)”
e2“Rates of leaf senescence were 3.4 and 2.1 times greater in the older hybrid than in the newer hybrids during the first and second half of the grain-filling period”
Claim · model-written summary
The older hybrid had a leaf senescence rate 2.1 times greater than the newer hybrids in the second half of grain filling.
- Material
- older hybride2
- Outcome
- Rates of leaf senescencee2
- Direction
- greatere2
- Value
- 2.1e2
- Comparator
- newer hybridse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize (Zea mays L.)”
e2“Rates of leaf senescence were 3.4 and 2.1 times greater in the older hybrid than in the newer hybrids during the first and second half of the grain-filling period”
Claim · model-written summary
Maximum leaf area index at silking was greater in newer hybrids than in the older hybrid.
- Material
- newer hybridse3
- Outcome
- Maximum leaf area index (LAI) at silkinge3
- Direction
- greatere3
- Comparator
- older hybride3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize (Zea mays L.)”
e3“Maximum leaf area index (LAI) at silking was greater in newer hybrids than in the older hybrid”
Claim · model-written summary
Leaf senescence in the first half of grain filling increased from the medium to the highest plant population density.
- Organ / stage
- first half of the grain-filling periode4
- Treatment
- plant population densitye4
- Outcome
- leaf senescencee4
- Direction
- increasede4
- Comparator
- mediume4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize (Zea mays L.)”
e4“During the first half of the grain-filling period, leaf senescence increased from the medium to the highest plant population density”
Claim · model-written summary
For the older hybrid, the rate of leaf senescence in the second half of grain filling declined as plant population density increased.
- Material
- older hybride5
- Organ / stage
- second half of the grain-filling periode5
- Treatment
- plant population densitye5
- Outcome
- rates of senescencee5
- Direction
- declinede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize (Zea mays L.)”
e5“rates of senescence during the second half of the grain-filling period declined with an increase in plant population density for the older hybrid”
Claim · model-written summary
For the newer hybrids, the rate of leaf senescence was lowest at the medium plant population density.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize (Zea mays L.)”
e6“rates were lowest at the medium plant population density for the newer hybrids”
Claim · model-written summary
Leaf senescence showed a top–bottom profile in the second half of grain filling, with central canopy leaves senescing last, more marked in the newer hybrids.
- Organ / stage
- leaves in the central section of the canopye7
- Outcome
- top–bottom profile of leaf senescencee7
- Qualifier
- more marked in the newer hybridse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize (Zea mays L.)”
e7“A top–bottom profile of leaf senescence was observed during the second half of the grain-filling period, with leaves in the central section of the canopy being the last leaves to senesce, and this phenomenon was more marked in the newer hybrids”
The same questions in other papers
density · quality: postharvest · Zea mays (maize)Positive and negative results
6 papers in the same direction as this paper · 5 in the opposite direction
- negative
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8 papers more in this group
See all 12 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.