Genetic Trends in Winter Wheat Grain Quality with Dual‐Purpose and Grain‐Only Management Systems

Hard winter wheat (Triticum aestivum L.) grain harvested from a dual‐purpose (forage plus grain) crop is often perceived by users to have inferior end‐use quality compared with that of a grain‐only crop. In this paper, we determine if that perception has a scientific basis and if long‐term genetic changes in grain quality are equally expressed under two management systems commonly practiced in the southern Great Plains. Uniform trials were established under grain‐only and dual purpose management systems, each featuring whole‐plot treatments of a foliar fungicide and split‐plot treatments of 12 hard red winter (HRW) wheat cultivars spanning nearly 80 yr of genetic improvement. The study was conducted for 4 yr at the Wheat Pasture Research Center near Marshall, OK. Dual‐purpose experiments were grazed from November through late February or early March of each year. Variables measured were kernel hardness, grain protein, flour yield, mixing time and tolerance, large‐kernel fraction, kernel weight, and kernel diameter. The effect of fungicide treatment was not significant. Cultivar × system interactions were generally absent, and the correlation between management systems varied from r = 0.74 to 0.99 (P < 0.01), indicating a high level of consistency in quality between systems. Kernel weight in the dual‐purpose system did not reach the same level as in the grain‐only system for some cultivars, though kernel diameter was not negatively affected. Grain protein and dough strength, measured by mixing time and tolerance, were unaffected by management system. Significant genetic progress was observed in both systems for only the physical quality attributes (kernel weight and diameter, and percent large kernels). With exception of kernel weight, we detected no detrimental effect of the dual‐purpose management system on cultivar performance, or on cultivar differences associated with breeding, for several characteristics commonly used to estimate bread wheat quality.