Genetic Variation of Nitrogen-Use Efficiency in Aegilops tauschii

The wild grass Aegilops tauschii, the D-genome ancestor of bread wheat, provides novel variation for many useful traits for wheat breeding. However, little is known about their genetic potential for tolerance/adaptation to abiotic stresses, especially to low soil nitrogen (N). Here we report the genetic variation of thirty Ae. tauschii accessions originated from different geographical areas for nitrogen-use efficiency (NUE) in the hydroponic and potted experiments. Significant variation of biomass, shoot N accumulation, and NUE in the low N treatment was observed among the Ae. tauschii accessions at both seedling and adult stages. We found that N accumulation ability was more important than N utilization for biomass production in the N-deficiency condition at seedling and adult stages. Five accessions, including Jing Y95, Jing Y126, Jing Y127, Jing Y191 and Jing Y195, showed high NUE at adult stage. However, Jing Y95, Jing Y126, Jing Y127, and Jing Y191, which had high spike dry matter, did not produce high volume of biomass at seedling stage. Therefore, the N tolerance/adaptation genotype selection at seedling stage might be ineffective if high spike weight is used as a genotypic selection criterion