Background <p>Breeding crops for enhanced understanding of apparent nitrogen use efficiency (NUE) requires understanding of phenotypic variations and underlying genetics. Improving NUE in Indian mustard is considered important to reduce nitrogen (N) fertilizer use without sacrificing crop yield. In the present study, 260 genotypes of <i>Brassica juncea</i> were field evaluated for seed yield and NUE-related traits at three N levels: N<sub>0</sub> (no added nitrogen), N<sub>50</sub> (50&#xa0;kg/ha nitrogen), and N<sub>100</sub> (100&#xa0;kg/ha nitrogen) for two years.</p> Results <p>N response in plants varied depending on the dose of nitrogen applied and tended to vary across genotypes and the plant’s developmental stages. A pooled analysis of variance revealed significant variations in the diversity-fixed foundation set for all the traits. Genotypes 252,026, PBR-91, EJ-15, IM-22, YSRL-9, RE-14, and IM-18 recorded high NUE at low N levels. These also showed improved crop performance under high N. Association analysis and principal component analysis revealed positive associations between seed yield and NUE. Associative transcriptomics enabled the prediction of 15 candidate genes for association with NUE, N uptake efficiency (NUpE), and N utilization efficiency (NUtE). Notable among these were: <i>NRT1.7</i>,<i> AAP5</i>, and <i>PTR1</i>. These are major nitrogen, amino acid, and protein transporter genes. Another significant amino acid transporter gene, <i>AAP5</i>, appeared associated with NUE under limited N conditions.</p> Conclusions <p>Breeding for high NUE will be aided by sequence information for predicted candidate genes. Molecular pathways controlling nitrogen assimilation, transport, and redistribution within plants can be revealed by these genes.</p>

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Underpinning regions associated with nitrogen use efficiency in Brassica juncea L. Czern: using associative transcriptomics approach

  • Akshita Awasthi,
  • Indu Rialch,
  • Harjeevan Kaur,
  • Sanjula Sharma,
  • Andrea L. Harper,
  • Lenka Havlickova,
  • Ian Bancroft,
  • Surinder S. Banga

摘要

Background

Breeding crops for enhanced understanding of apparent nitrogen use efficiency (NUE) requires understanding of phenotypic variations and underlying genetics. Improving NUE in Indian mustard is considered important to reduce nitrogen (N) fertilizer use without sacrificing crop yield. In the present study, 260 genotypes of Brassica juncea were field evaluated for seed yield and NUE-related traits at three N levels: N0 (no added nitrogen), N50 (50 kg/ha nitrogen), and N100 (100 kg/ha nitrogen) for two years.

Results

N response in plants varied depending on the dose of nitrogen applied and tended to vary across genotypes and the plant’s developmental stages. A pooled analysis of variance revealed significant variations in the diversity-fixed foundation set for all the traits. Genotypes 252,026, PBR-91, EJ-15, IM-22, YSRL-9, RE-14, and IM-18 recorded high NUE at low N levels. These also showed improved crop performance under high N. Association analysis and principal component analysis revealed positive associations between seed yield and NUE. Associative transcriptomics enabled the prediction of 15 candidate genes for association with NUE, N uptake efficiency (NUpE), and N utilization efficiency (NUtE). Notable among these were: NRT1.7, AAP5, and PTR1. These are major nitrogen, amino acid, and protein transporter genes. Another significant amino acid transporter gene, AAP5, appeared associated with NUE under limited N conditions.

Conclusions

Breeding for high NUE will be aided by sequence information for predicted candidate genes. Molecular pathways controlling nitrogen assimilation, transport, and redistribution within plants can be revealed by these genes.