Nitrogen fertilizer complements breeding in improving yield and quality of milling oat

A four-level nitrogen (N) fertilizer study was conducted for nine diverse oat (Avena sativa L.) cultivars at three geographically diverse locations in Canada in 2013 and 2014 to study the effects of N fertilizer on grain yield and important quality parameters of milling oat. Analysis of variance and biplot analysis were used to interpret the multifactor, multitrait data. The findings are: (i) N fertilizer up to 150 kg ha-1 led to simultaneous and statistically significant improvement of grain yield, milling quality (groat content and proportion of undehulled kernels), and compositional quality (β-glucan, protein, and oil concentrations), despite some N × genotype and N × environment interactions. (ii) β-Glucan and oil concentrations were much more strongly determined by genotype than by N fertilizer; groat content and proportion of undehulled kernels were slightly more strongly determined by genotype than by N fertilizer; protein was similarly determined by genotype and N fertilizer; and grain yield was much more determined by N fertilizer than by genotype. (iii) Nitrogen fertilizer effectively increased the yield of high-bglucan, low-yielding cultivars but had a limited (though statistically significant) effect in improving the β-glucan levels of cultivars that are low in β-glucan. (iv) Cultivars differed in the extent of response to N fertilizer, so it is necessary to develop cultivar-specific N management plans for different cultivars. It is proposed to use N fertilizer to improve yield (and, to a lesser extent, quality parameters) to complement breeding prioritizing superior quality (high β-glucan in particular) and lodging resistance.