Cultivar and Nitrogen Effects on Yield and Grain Protein in Irrigated Durum Wheat, 2012

The grain yield and nitrogen use efficiency of durum wheat vary in response to genotypic and nitrogen fertilization were studied in field during two growth seasons. The aim of this study was to evaluate the effects the N fertilizer rate on grain yield and quality under irrigated desert conditions in relation to N utilization. Six durum wheat cultivars (Duraking, Havasu, Kronos, Ocotillo, Orita, Topper) were grown in field trails under irrigated regimes at five N levels (0, 65, 110, 160, 240 lbs/acre) in 2010-2011 and six N levels (0, 65, 110, 160, 240, 360 kg ha -1 ) in 2011-2012 at Maricopa Ag Center. The results showed the varieties and N levels both significantly affected grain yield, grain protein concentration, and nitrogen use efficiency. A simple and rapid method to measure crop N status using SPAD meters was also developed. The results showed that using the differences in SPAD readings between the first and second fully expanded leaves is a useful way to improve effectiveness of SPAD meters in durum wheat N management.