High yielding wheat in the northern region: impact of nitrogen fertilisation on grain yield and quality in modern cultivars

Abstract

Season to season variability in grain yields is the main factor determining farmers’ conservative investment strategies in dryland cropping. Yield differences among wheat cultivars and its responsiveness to resource availability are usually related to grain number per m2. The experience from Australia suggests that part of the low yields in dryland conditions might be due to low N availability, and that water use efficiency, yield, and grain quality could then be significantly improved by increasing N fertilizers rates. In this study, grain yield and quality were characterised for two recently released cultivars known to contrast for protein content. Crops were grown at Gatton, Queensland, under rainfed and irrigated conditions, and with three N levels. The aim of this study was to determine and quantify differences in yield and grain quality between different modern wheats grown in contrasting N and water conditions. Yield was significantly related to total dry biomass at maturity. Cultivar Suntop achieved higher biomass and yield than Spitfire beyond the treatments imposed, while Spitfire had a significantly greater percentage of grain protein than Suntop.