An experiment was carried out at Embrapa Rice and Beans, Santo Antônio de Goiás, Goiás State, Brazil, under no-tillage in the soybean mulch to evaluate the effects of nitrogen doses on the solar radiation use efficiency, leaf area index in the anthesis, biomass in the anthesis, in the physiological maturation and grain yield of two wheat cultivars. A randomized block design in subdivided plots, with four replications was used. In the plots five nitrogen topdressing doses, 0, 50, 100, 150, and 200 kg ha-1 were established and in the subplots, the cultivars Embrapa 22 and Embrapa 42. The cultivars differed only in relation to biomass in anthesis. The analyzed variables showed a quadratic response to nitrogen doses. Wheat grain yield response to nitrogen was due to the effect of this nutrient in the leaf area index, that affected solar radiation use efficiency and biomass, which showed a positive correlation with grain yield. Under low nitrogen availability, grain yield showed higher correlation to biomass accumulated in the anthesis than to that accumulated in the physiological maturation.
Triticum aestivum; no-tillage; anthesis; maturation
