Abstract
The biological improvement of fertilizer nitrogen use efficiency (NUE) is hampered by the poor characterization of the phenotype and genotype for crop N response and NUE. In an attempt to identify phenotypic traits for N-response and NUE in the earliest stages of plant growth, we analysed the N-responsive germination, respiration, urease activities and root/shoot growth of 21 Indica genotypes of rice (O. sativa var. Indica). We found that N delays germination from 0 to 12 hrs in a genotype-dependent and source-dependent manner, especially with urea and nitrate. We identified contrasting groups of fast germinating genotypes such as Aditya, Nidhi and Swarnadhan, which were also least delayed by N and slow germinating genotypes such as Panvel1, Triguna and Vikramarya, which were also most delayed by N. Oxygen uptake measurements in the seeds of contrasting genotypes revealed that they were affected by N source in accordance with germination rates, especially with urea. Germinating seeds were found to have endogenous urease activity, indicating the need to explore genotypic differences in the effective urea uptake and metabolism, which remain unexplored so far. Urea was found to significantly inhibit early root growth in all genotypes but not shoot growth. Field evaluation of 15 of the above genotypes clearly showed that germination rates, crop duration and yield are linked to NUE. Slow germinating genotypes had longer crop duration and higher yield even at lower N, indicating their higher N use efficiency, relative to fast germinating or short duration genotypes. Moreover, longer duration genotypes suffered lesser yield losses at reduced N levels as compared to short duration genotypes, which is also a measure of their NUE. Together, these results indicate the potential of germination rates, crop duration, urea utilization and its effect on root growth in the development of novel phenotypic traits for screening genotypes and crop improvement for N use efficiency, at least in rice.
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Claims 13
Claim · model-written summary
N delayed rice germination by 0 to 12 hrs depending on genotype and source, especially urea and nitrate.
- Taxon
- Rice
Oryza sativat0 - Treatment
- Ne0
- Outcome
- germinatione0
- Direction
- delayse0
- Value
- 0 to 12 hrse0
- Qualifier
- genotype-dependent and source-dependente0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N delays germination from 0 to 12 hrs in a genotype-dependent and source-dependent manner, especially with urea and nitrate”
t0“Rice”
Claim · model-written summary
Aditya, Nidhi and Swarnadhan germinated quickly and were least delayed by N.
- Taxon
- RiceOryza sativat0
- Material
- Aditya, Nidhi and Swarnadhane0
- Outcome
- fast germinatinge0
- Direction
- least delayede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fast germinating genotypes such as Aditya, Nidhi and Swarnadhan, which were also least delayed by N”
t0“Rice”
Claim · model-written summary
Panvel1, Triguna and Vikramarya germinated slowly and were most delayed by N.
- Taxon
- RiceOryza sativat0
- Material
- Panvel1, Triguna and Vikramaryae0
- Outcome
- slow germinatinge0
- Direction
- most delayede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“slow germinating genotypes such as Panvel1, Triguna and Vikramarya, which were also most delayed by N”
t0“Rice”
Claim · model-written summary
Seed oxygen uptake varied with N source in accordance with germination, especially urea.
- Taxon
- RiceOryza sativat0
- Organ / stage
- seedse0
- Treatment
- N sourcee0
- Outcome
- Oxygen uptakee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oxygen uptake measurements in the seeds of contrasting genotypes revealed that they were affected by N source in accordance with germination rates, especially with urea”
t0“Rice”
Claim · model-written summary
Germinating rice seeds had endogenous urease activity.
- Taxon
- RiceOryza sativat0
- Organ / stage
- Germinating seedse0
- Gene
- ureasee0
- Outcome
- endogenous urease activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Germinating seeds were found to have endogenous urease activity”
t0“Rice”
Claim · model-written summary
Urea significantly inhibited early rice root growth.
- Taxon
- RiceOryza sativat0
- Organ / stage
- roote0
- Treatment
- Ureae0
- Outcome
- early root growthe0
- Direction
- inhibite0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Urea was found to significantly inhibit early root growth in all genotypes but not shoot growth”
t0“Rice”
Claim · model-written summary
Urea did not inhibit shoot growth.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Urea was found to significantly inhibit early root growth in all genotypes but not shoot growth”
t0“Rice”
Claim · model-written summary
Field evaluation linked germination rates, crop duration and yield to NUE.
- Taxon
- RiceOryza sativat0
- Organ / stage
- germinatione0
- Outcome
- NUEe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“germination rates, crop duration and yield are linked to NUE”
t0“Rice”
Claim · model-written summary
Slow germinating rice genotypes had longer crop duration.
- Taxon
- RiceOryza sativat0
- Material
- Slow germinating genotypese0
- Outcome
- crop duratione0
- Direction
- longere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Slow germinating genotypes had longer crop duration”
t0“Rice”
Claim · model-written summary
Slow germinating genotypes had higher yield at lower N than fast or short-duration genotypes.
- Taxon
- RiceOryza sativat0
- Material
- Slow germinating genotypese0
- Outcome
- yielde0
- Direction
- highere0
- Comparator
- fast germinating or short duration genotypese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Slow germinating genotypes had longer crop duration and higher yield even at lower N, indicating their higher N use efficiency, relative to fast germinating or short duration genotypes”
t0“Rice”
Claim · model-written summary
Slow germinating genotypes had higher NUE than fast or short-duration genotypes.
- Taxon
- RiceOryza sativat0
- Outcome
- N use efficiencye0
- Direction
- highere0
- Comparator
- fast germinating or short duration genotypese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“indicating their higher N use efficiency, relative to fast germinating or short duration genotypes”
t0“Rice”
Claim · model-written summary
Longer-duration genotypes had lesser yield losses under reduced N than short-duration genotypes.
- Taxon
- RiceOryza sativat0
- Material
- longer duration genotypese0
- Outcome
- yield lossese0
- Direction
- lessere0
- Comparator
- short duration genotypese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“longer duration genotypes suffered lesser yield losses at reduced N levels as compared to short duration genotypes”
t0“Rice”
Claim · model-written summary
The authors proposed germination, crop duration, urea utilization and root response as screening traits for rice NUE improvement.
- Taxon
- riceOryza sativat0
- Outcome
- novel phenotypic traits for screening genotypes and crop improvement for N use efficiencye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“potential of germination rates, crop duration, urea utilization and its effect on root growth in the development of novel phenotypic traits for screening genotypes and crop improvement for N use efficiency”
t0“rice”
The same questions in other papers
nitrogen · growth · Oryza sativa (rice)Positive and negative results
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