Differences of nitrogen uptake and utilization between two homozygous mutants and their original cultivar of barley

Abstract

In order to explore the causes of differences of nitrogen use efficiency (NUE) between barley (Hordeum vulgare) mutants and wild type 'Hua 30', the accumulation and transportation of dry matter and nitrogen between mutants and wild type were characterized and their relationship with NUE were studied at two levels of nitrogen fertilizer applications. The results show that barley mutant A9-29 derived from ethyl methanesulfonate (EMS)-treated microspore mutagenesis was a high NUE line at low nitrogen level, while barley mutant SP Hua 30(15) derived from space mutagenesis combined with microspore culture was a high NUE line at high nitrogen level. The accumulation, transportation and distribution of the dry matter and nitrogen, the grain yield and NUE of two mutants were significantly different from those of 'Hua30' at different nitrogen levels. Regarding the grain yield and nitrogen content, A9-29 was significantly higher than 'Hua30' at low nitrogen level while SP Hua 30(15) was significantly higher than 'Hua30' at high nitrogen level, which was contributed by pre-anthesis dry matter/nitrogen translocation and post-anthesis dry matter/nitrogen accumulation. The increase of NUE in mutants is mainly due to the improvement of nitrogen uptake efficiency. The characterization of two mutants would not only provide promising germplasm resources for high NUE breeding, but also excellent experimental materials for the study on machanism of nitrogen absorption efficiency.