Nitrogen dose to maximize grain yield and quality of durum wheat depends on the water availability in Chilean Mediterranean environments

Paola Silva1*, Paola Aedo1, Edmundo Acevedo1, and Iván Matus2
Quality durum wheat (Triticum turgidum L. subsp. durum (Desf.) van Slageren) has the highest performance in climates with dry and hot summers. Chilean durum wheat has a low protein content. This research was carried out in two growing seasons in two Chilean localities, under two water conditions. The aim was to analyze the impact of N rate and application timing over yield and quality of durum wheat grain in the Mediterranean climate of central Chile. The field experiment was carried out with two durum wheat genotypes. For each experiment, there were two N factors: three rate N applied in durum wheat vegetative phase (0, 90, 210 kg N ha-1) and four rate N applied in the reproductive phase (0, 30, 60, 90 kg N ha-1). Therefore, the treatments were 12 combinations of N. Grain yield, biomass, and harvest index were affected by N application in the vegetative phase only. Both quantity and distribution of rainfall was the environmental factor that triggered three types of grain yield response to N fertilization: Environments in which the yield responds positively to N applications, environments without yield response to N applications, and environments in which the yield responds negatively to N applications. In an environment which the yield responds positively to N applications, the highest mean grain yield was 6309 kg ha-1, protein content reached 13% in the highest N applications. In an environment without yield response, grain yield, black point, and hectoliter weight did not change with N fertilization. In an environment in which the yield responds negatively to N applications, the lowest mean grain yield was 1960 kg ha-1, protein content increased to 16%, and hectoliter weight decreased below 79 kg hL-1 with 90 kg N ha-1 rate or higher.
Keywords: Black point, grain protein, hectoliter weight, nitrogen management, Triticum turgidum subsp. durum, yellowberry.
1Universidad de Chile, Facultad de Ciencias Agronómicas, casilla 1004, Santiago, Chile.
2Instituto de Investigaciones Agropecuarias, INIA Quilamapu, Av. Vicente Méndez 515, Chillán, Chile.
*Corresponding author (psilva@uchile.cl).