Comparison of four wheat cultivars for yield and protein response to nitrogen fertilizer

Abstract

Four wheat cultivars were compared for grain yield and grain protein response to nitrogen fertilizer at rates up to 135 and 336 kg N ha-1, in two field experiments, All varieties showed large responses to nitrogen in both years. The Mexican semi-dwarf WW15 and its white-grain derivative, Condor, yielded more than the standard cultivars Timgalen or Gatcher. Semi dwarf cultivars were found to respond significantly more to nitrogen than either Timgalen or Gatcher in the first year of these trials. Protein percentage of the grain was depressed by low rates of nitrogen in one year but increassd at higher rates. Gatcher and Condor had similar protein percentages; WW15 had the lowest and Timgalen the highest. Only Timgalen with high nitrogen reached a protein level for premium payment in the first year. In the second, all cultivars when fertilized qualified for similar premium payments per unit of land area. A simplified economic analysis showed that it was more profitable to grow and to fertilize the higher-yielding cultivars.