Abstract
This study investigated the impact of nitrogen (N) fertilization on the yield and grain filling (GF) characteristics of two conventional japonica rice varieties with distinct panicle types: Yangchan 3501 (large-panicle: spikelets per panicle > 150) and Nangeng 46 (medium-panicle: 100 < spikelets per panicle < 150). Field experiments were conducted over two growing seasons (2022–2023) with three N application rates (T1: 225 kg ha−1, T2: 270 kg ha−1, T3: 315 kg ha−1). Key measurements included tiller dynamics, panicle composition, GF parameters modeled using the Richards equation, and enzyme activities related to nitrogen metabolism (Fd-GOGAT, NR) and carbohydrate transport (α-amylase, SPS). Results showed that the yield increased with higher N levels for both varieties, with Yangchan 3501 achieving higher yields primarily through increased grains per panicle (15.65% rise under T3 vs. T1), while Nangeng 46 relied on panicle number (8.83% increase under T3 vs. T1). Nitrogen application enhanced Fd-GOGAT and NR activities, prolonging photosynthesis and improving GF rates, particularly in the inferior grains of Yangchan 3501 during middle and late stages. However, a high N reduced seed-setting rates and 1000-grain weight, with larger panicle types exhibiting a greater sensitivity to N-induced changes in branch structure and assimilate allocation. This study highlights that optimizing N management can improve nitrogen-metabolism enzyme activity and GF efficiency, especially in large-panicle rice, while medium-panicle types require higher N inputs to maximize panicle number. These findings provide actionable insights for achieving high yields and efficient nutrient use in conventional rice cultivation.
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Claims 9
Claim · model-written summary
Rice yield increased with higher nitrogen levels in both varieties.
- Taxon
- japonica rice
_by_Augustus_Binu.jpg?width=60)
Oryza sativa Japonica Groupe0 - Treatment
- higher N levelse1
- Outcome
- yielde1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_by_Augustus_Binu.jpg?width=500)
Verbatim
e0“two conventional japonica rice varieties”
e1“yield increased with higher N levels for both varieties”
Claim · model-written summary
Yangchan 3501 increased grains per panicle by 15.65% under T3 compared with T1.
- Taxon
- japonica riceOryza sativa Japonica Groupe0
- Material
- Yangchan 3501e2
- Treatment
- T3e2
- Outcome
- grains per paniclee2
- Direction
- increasede2
- Value
- 15.65%e2
- Comparator
- T1e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two conventional japonica rice varieties”
e2“Yangchan 3501 achieving higher yields primarily through increased grains per panicle (15.65% rise under T3 vs. T1)”
Claim · model-written summary
Nangeng 46 increased panicle number by 8.83% under T3 compared with T1.
- Taxon
- japonica riceOryza sativa Japonica Groupe0
- Material
- Nangeng 46e3
- Treatment
- T3e3
- Outcome
- panicle numbere3
- Direction
- increasee3
- Value
- 8.83%e3
- Comparator
- T1e3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two conventional japonica rice varieties”
e3“Nangeng 46 relied on panicle number (8.83% increase under T3 vs. T1)”
Claim · model-written summary
Nitrogen application enhanced Fd-GOGAT and NR enzyme activities in rice.
- Taxon
- japonica riceOryza sativa Japonica Groupe0
- Treatment
- Nitrogen applicatione4
- Gene
- Fd-GOGAT and NRe4
- Outcome
- activitiese4
- Direction
- enhancede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two conventional japonica rice varieties”
e4“Nitrogen application enhanced Fd-GOGAT and NR activities”
Claim · model-written summary
Nitrogen application improved grain-filling rates in the inferior grains of Yangchan 3501 during middle and late stages, while prolonging photosynthesis.
- Taxon
- japonica riceOryza sativa Japonica Groupe0
- Material
- Yangchan 3501e5
- Organ / stage
- inferior grainse5
- Treatment
- Nitrogen applicatione5
- Outcome
- GF ratese5
- Direction
- improvinge5
- Qualifier
- middle and late stagese5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two conventional japonica rice varieties”
e5“Nitrogen application enhanced Fd-GOGAT and NR activities, prolonging photosynthesis and improving GF rates, particularly in the inferior grains of Yangchan 3501 during middle and late stages”
Claim · model-written summary
High nitrogen reduced seed-setting rates and 1000-grain weight.
- Taxon
- japonica riceOryza sativa Japonica Groupe0
- Treatment
- high Ne6
- Outcome
- seed-setting rates and 1000-grain weighte6
- Direction
- reducede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two conventional japonica rice varieties”
e6“a high N reduced seed-setting rates and 1000-grain weight”
Claim · model-written summary
Larger panicle types were more sensitive to N-induced changes in branch structure and assimilate allocation.
- Taxon
- japonica riceOryza sativa Japonica Groupe0
- Material
- larger panicle typese7
- Outcome
- sensitivity to N-induced changese7
- Direction
- greatere7
- Qualifier
- branch structure and assimilate allocatione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two conventional japonica rice varieties”
e7“larger panicle types exhibiting a greater sensitivity to N-induced changes in branch structure and assimilate allocation”
Claim · model-written summary
Optimizing nitrogen management can improve nitrogen-metabolism enzyme activity and grain-filling efficiency, especially in large-panicle rice.
- Taxon
- rice
Oryza sativae1 - Outcome
- nitrogen-metabolism enzyme activity and GF efficiencye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“optimizing N management can improve nitrogen-metabolism enzyme activity and GF efficiency, especially in large-panicle rice”
Claim · model-written summary
Medium-panicle rice types require higher nitrogen inputs to maximize panicle number.
- Taxon
- japonica riceOryza sativa Japonica Groupe0
- Material
- medium-panicle typese1
- Treatment
- higher N inputse1
- Outcome
- panicle numbere1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two conventional japonica rice varieties”
e1“medium-panicle types require higher N inputs to maximize panicle number”
The same questions in other papers
nitrogen · yield · Oryza sativa (rice)Positive and negative results
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