Impact of N fertilization in agronomic and flour ntritional traits

Trabajo presentado en el I Simposio Español de Fisiología y Mejora de Cereales, celebrado en Zaragoza (España), los días 9 y 10 de abril de 2018The availability and management of N are major determinants of crop productivity and the associated environmental agro-ecosystems. Within this context, it is crucial to improve crop N use efficiency (NUE). The aim was to study the influence of N fertigation on yield and grain quality of durum wheat. In a first stage, 20 cultivars were watered with high N (HN, ½ Hoagland nutrient solution), whereas the other half was watered with low N (LN, modified ½ Hoagland with one-third of N). Based on yield and NUE data, six genotypes were selected for a secondary study in which deep flour nutritional traits were characterized. More specifically, together with the agronomic characterization, grain quality analyses were assessed to characterize mineral composition, carbohydrate concentration (soluble sugars and starch), glutenin and gliadin concentration, polyphenol quantitative profile, antioxidant activity, and dough viscosity profile. Obtained data showed that crop yield increased in HN whereas no differences were detected among genotypes. Mineral composition was not affected by N but was genotype-dependent. In fact, low yielding genotypes showed higher Ca, Cu, Fe, Mn and Zn concentrations. LN fertigation increased grain carbohydrate concentrations, showing genotypes with high yield the highest amounts. Furthermore, the increase of starch concentration under LN increased dough viscosity. Nitrogen supply improved grain quality through increases in gliadin and glutenin concentration, although without differences among genotypes. Contrary to this, under LN, the low yielding genotypes had the highest values. Flour total phenol concentration was significantly higher and bioaccessible phenols lower under HN. Low yielding genotypes had the highest values of total and bioaccessible phenols, and antiradical activity. Overall, our data show that decreasing the amount of N to one-third ensures durum wheat agronomic and quality traits, showing genotype 3 an efficient response to low N availability.Peer reviewe