Yield and Yield Components of Winter Wheat Cultivars as Influenced by Management—A Regional Study

Winter wheat (Triticum aestivum L.) yields in the USA average less than half the wheat yields achieved in the United Kingdom. Much of this difference is attributed to differences in management systems. This study was conducted to determine the effect of management systems on the yield and yield components of winter wheat cultivars adapted to the Great Lakes region of the USA, and to evaluate the environmental influences on the response of cultivars to different management inputs. Field studies were conducted in 1985 and 1986 near Columbus, OH, East Lansing, MI, and Madison, WI, for a total of six environments. The study consisted of nine cultivars subjected to each of six management treatments (MT) differing in seeding and N rates, the use of a fungicide, and a plant growth regulator. Care was taken to standardize procedures such that the seed of each cultivar at each location was of the same seed lot. Likewise, fungicides, herbicides, and the plant growth regulator were acquired from the same production lot and were applied identically as to rate, amount of carrier, pressure, and growth stage. Seeding rates were established as seeds per foot of row and the same N form (urea) was aplied at specific growth stages, although the rate was adapted to the soil type and previous crop so that similar amounts of N would be available to the crop at each location. Prior to harvest, grain heads were collected from each plot for yield component analysis. Location, cultivar, and the interaction of the two were significant for yield and its components, while management treatments affected only yield and heads per square foot. The cultivar‐by‐management interaction was significant for yield and kernel weight. Location, management, cultivar, and all their interactions were significant for yield. Yield differences due to management were reflected primarily in differences in the number of heads per square foot, while yield differences due to cultivar were reflected in all three yield components. Management systems must be specific for both cultivar and environment. Yield differences will most likely be due to the number of heads per unit area, which is influenced by both seeding rate and tillering capacity of the cultivar, but the number of kernels per head and kernel size can account for large yield differences in some cultivars if suitable conditions exist.