Response of seedling traits to low nitrogen stress and selection of low nitrogen tolerance germplasm of oat

To clarify the effects of low nitrogen stress on oat seedling growth, and select oat germplasm with high tolerance to low nitrogen. In this study, 19 oat germplasm resources were used as materials to analyze the biomass and low nitrogen tolerance coefficient of oat under normal nitrogen (2 mmol·L⁻¹ NH₄NO₃) and low nitrogen (0.2 mmol·L⁻¹ NH₄NO₃) conditions by hydroponic method at the seedling stage. Per the low nitrogen tolerance coefficient of straw dry weight and plant dry weight, 5 low nitrogen tolerant germplasm resources and 5 low nitrogen sensitive germplasm resources were screened. And 11 indexes including chlorophyll content, biomass, and root morphology of 10 oat germplasm resources were further determined by double-screening. The results demonstrated that under low nitrogen stress, straw dry weight, plant height, and leaf SPAD values were significantly decreased (P < 0.05), while root dry weight, root-shoot ratio, root volume, root surface area, and root tip number were significantly increased (P < 0.05). Variance analysis principal component analysis and correlation analysis showed that plant height, straw dry weight, root dry weight, root surface area, and root tip number could be used for evaluating the low nitrogen tolerance of oats. Per the comprehensive evaluation value of low nitrogen tolerance (D), two low nitrogen tolerance germplasms ZY004067 and ZY004068, and three nitrogen sensitive germplasms ZY004085, ZY004101, and ZY004093 were screened.