Grain yield and quality of two durum wheat cultivars grown in Canterbury

High yields of high quality durum. wheat are required to improve New Zealand's durum. flour and pasta industries. In this study the effect of the application of nitrogen (N) fertiliser on grain yield and quality of the two cultivars, CRDW17 and Waitohi, was investigated in a field experiment in Canterbury. Fertiliser was applied at tillering (0 or 175 kg N/ha) and at flag leaf emergence (0, 40 or 80 kg N/ha). The grain yield with no N applied was 4.5 t/ha compared with 7.5 t/ha for both the early N treatment and the early plus late N treatment. Late N increased yields by 0.5 t/ha when no N had been applied at tillering. Rainfall just before harvest caused sprout damage that was more severe in cv. CRDW17 than in cv. Waitohi. Mean grain and flour protein percentage was higher for cv. Waitohi (12.4%) than for cv. CRDW17 (11.7%). The late application of 80 kg N/ha increased flour protein content in both cultivars, with average values increasing from 11.2% to 12.8%. Grain colour was measured with a chroma meter. Higher values of the parameter (b*) indicated a more yellow colour which is preferred for pasta production. The mean value of b* over all treatments was greater for cv. Waitohi (24.4) than cv. CRDW17 (23.8). However, b* values for flour were higher in cv. CRDW17 (18.9) than cv. Waitohi (17.5). Grain b* value decreased from 24.7 to 23.5 as a result of early N application, but flour b* values increased from 17.7 to 18.7. Late N application reduced the yellowness of grain from 25.3 to 23.9 after 40 kg N/ha and to 23.0 following 80 kg N/ha. Flour b* values were increased from 17.9 to 18.3 for both rates of late application. Fortuitously, N applications that produced the highest grain yield and flour protein content also gave the most preferred flour colour.