Maximum Attainable Wheat Yield and Resource‐Use Efficiency in the Southern Great Plains

Abstract

ABSTRACTMaximum reported grain yields for hard red winter wheat (Triticum aestivum L.) in the southern Great Plains range from 6 to 8 Mg ha–1 and are significantly lower than yields achieved in other regions of the world. The lack of empirical data for wheat under nonlimiting conditions in this region, however, suggests that maximum reported grain yields for the region might not represent maximum attainable yields. Our objective was to perform the agronomic characterization of wheat grown under nonlimiting conditions across the southern Great Plains. Four dryland and two irrigated fields were sown to ‘Iba’ winter wheat in the 2012–2013 growing season and repeated during 2013–2014 in central Oklahoma. Fields were intensively managed for fertility for maximum yield and freedom from weeds, insects, and disease. Aboveground dry matter at maturity ranged from 9.95 to 20.5 Mg ha–1, but harvest index (HI) did not surpass 0.41 and grain yields ranged from 3.06 to 7.68 Mg ha–1. The highest yield was achieved under irrigated conditions in 2013–2014, but one dryland site produced 7.11 Mg ha–1 grain in 2012–2013. Maximum radiation‐use efficiency (RUE) ranged from 0.8 to 1.9 g MJ–1 and water‐use efficiency (WUE) from 7.8 to 12.6 kg ha–1 mm–1. The wheat characteristics measured in this study were near or above maximum values reported in the literature for the region, and our data provide empirical evidence to support maximum attainable wheat yields of 7.68 Mg ha–1 when wheat is grown under nonlimiting conditions in the southern Great Plains.