Advances in Barley Breeding for Improving Nitrogen Use Efficiency

Abstract

Crop breeding for high nitrogen use efficiency (NUE) or tolerance to low nitrogen fertilization is thought to be an ideal solution to reduce the cost, carbon footprint, and other environmental problems caused by the excess use of nitrogen fertilizers. As a model plant for cereal crops, barley has many advantages, including good adaptability, a short growth period, and high natural stress resistance or tolerance. Therefore, research on improving NUE in barley is not only beneficial for nitrogen-efficient barley breeding but will also inform NUE improvement in other cereal crops. In this review, recent progress in understanding barley’s response to nitrogen nutrition, evaluation of NUE or low-nitrogen tolerance, quantitative trait loci (QTL) mapping and gene cloning associated with improving NUE, and breeding of nitrogen-efficient barley is summarized. Furthermore, several biotechnological tools that could be used for revealing the molecular mechanisms of NUE or breeding for improving NUE in barley are introduced, including GWAS, omics, and gene editing. The latest research ideas in unraveling the molecular mechanisms of improving NUE in other crops are also discussed. Thus, this review provides a better understanding of improving the NUE of barley and some directions for future research in this area.

QTL mapping of nitrogen use efficiency traits at the seedling and maturity stages under different nitrogen conditions in barley (Hordeum vulgare L.)

“…NPF2.12 indirectly regulates root growth and NUE by activating NO signalling under LN conditions (Siddiqui et al, 2023). Transcription factor HvNLP2 mediates nitrate signalling and affects NUE in barley (Chen et al, 2022). Q‐GNN0‐2008‐MQM for grain N content was identified on barley chromosome 2H (Saal et al, 2011).…”

“…Kindu et al (2014) detected a few QTLs for NUE traits on barley chromosome arm 3HL. HvNRT2.1 might also be beneficial for improving the NUE in barley (Chen et al, 2022; Gao et al, 2022). Although there have been extensive advancements in the genetic knowledge of NUE traits at maturity, it remains largely unknown at the seedling stage.…”

Advances in Molecular Exploration of Crop Plants under Environmental Stresses from Genetic and Genomic Perspectives

“…Lastly, in their review article, Chen et al [28] summarized recent advances in the improvements in the efficient use of nitrogen based on barley (Hordeum vulgare L.) breeding. Due to the importance of reducing the various types of cost and identifying effective solutions to the environmental problems (e.g., increased carbon footprint) resulting from the excess application of nitrogen fertilizers, both high nitrogen use efficiency or tolerance to low nitrogen fertilization are considered to be the ideal strategies to deal with the issues of the application of nitrogen fertilization worldwide.…”