Improving Crop Nitrogen Use Efficiency

Raghuram, Nandula; Sharma, Nikhil

doi:10.1016/b978-0-444-64046-8.00222-6

Cited by 26 publications

(37 citation statements)

References 33 publications

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“…A major challenge for biological improvement of NUE in any crop has been the incomplete characterization of the phenotype and genotype for NUE, as is the lack of low-input screening programs ( Mandal et al, 2018 ; Raghuram and Sharma, 2019 ) with rare exceptions ( Rao et al, 2018 ). Rice is an excellent target crop to improve NUE, but the characterization of its phenotype is neither comprehensive nor complete, despite considerable progress, as detailed in the Introduction.…”

Section: Discussionmentioning

confidence: 99%

“…Functional genomics provided us with thousands of genes involved in N-response ( Mandal et al, 2018 ; Raghuram and Sharma, 2019 ), including our own data on rice ( Pathak et al, 2020 , GSE12940, GSE20924, and GSE140257). Our delineation of the parameters constituting the NUE phenotype fills this gap.…”

Section: Discussionmentioning

confidence: 99%

“…Cereals consume most of the N fertilizer globally, especially the predominantly rice growing countries of Asia and Latin America ( Zhang et al, 2015 ). Nitrogen use efficiency (NUE) is defined in many ways including uptake, utilization or photosynthetic efficiency, but agronomically understood as output–input ratio and expressed in cereals as grain yield per unit N input ( Raghuram and Sharma, 2019 ). Rice is an ideal target crop to improve NUE because of its lowest NUE among cereals ( Zhang et al, 2015 ), its huge genetic diversity that includes wild relatives and a vast post-genomic resource base.…”

Section: Introductionmentioning

confidence: 99%

“…While some improvement in agronomic NUE can be attained through slow-release fertilizers ( Li T. et al, 2018 ), bio-fertilizers ( Bargaz et al, 2018 ; Quevedo-Amaya et al, 2020 ) and crop management practices ( Guo et al, 2017 ; Cui et al, 2018 ; Santiago-Arenas et al, 2020 ), the improvement of inherent plant NUE has to be tackled biologically. The lack of a well-defined phenotype for N response and NUE has hampered biological interventions for crop improvement ( Mandal et al, 2018 ; Raghuram and Sharma, 2019 ; Sinha et al, 2020 ). However, there has been some recent progress in identifying phenotypic parameters for N-response/NUE in model plants ( Li et al, 2017 ).…”

Section: Introductionmentioning

confidence: 99%

“…There have been several attempts to find genes involved in N-response through functional genomics ( Pathak et al, 2020 ). Single gene transgenics were used to improve N-uptake, assimilation or remobilization, but with little improvement of NUE, if any ( Mandal et al, 2018 ; Raghuram and Sharma, 2019 ; Sinha et al, 2020 ). Recent attempts in rice have been more encouraging ( Fang et al, 2013 ; Fan et al, 2014 ; Sun et al, 2014 ), especially when NAR2.1 and NRT2.3a were co-overexpressed ( Chen et al, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

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Nitrogen Use Efficiency Phenotype and Associated Genes: Roles of Germination, Flowering, Root/Shoot Length and Biomass

et al. 2021

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Crop improvement for Nitrogen Use Efficiency (NUE) requires a well-defined phenotype and genotype, especially for different N-forms. As N-supply enhances growth, we comprehensively evaluated 25 commonly measured phenotypic parameters for N response using 4 N treatments in six indica rice genotypes. For this, 32 replicate potted plants were grown in the green-house on nutrient-depleted sand. They were fertilized to saturation with media containing either nitrate or urea as the sole N source at normal (15 mM N) or low level (1.5 mM N). The variation in N-response among genotypes differed by N form/dose and increased developmentally from vegetative to reproductive parameters. This indicates survival adaptation by reinforcing variation in every generation. Principal component analysis segregated vegetative parameters from reproduction and germination. Analysis of variance revealed that relative to low level, normal N facilitated germination, flowering and vegetative growth but limited yield and NUE. Network analysis for the most connected parameters, their correlation with yield and NUE, ranking by Feature selection and validation by Partial least square discriminant analysis enabled shortlisting of eight parameters for NUE phenotype. It constitutes germination and flowering, shoot/root length and biomass parameters, six of which were common to nitrate and urea. Field-validation confirmed the NUE differences between two genotypes chosen phenotypically. The correspondence between multiple approaches in shortlisting parameters for NUE makes it a novel and robust phenotyping methodology of relevance to other plants, nutrients or other complex traits. Thirty-Four N-responsive genes associated with the phenotype have also been identified for genotypic characterization of NUE.

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Section: Discussionmentioning

confidence: 99%