A two-year study comparing wheat plantings resulted in blends of complementary varieties producing an average of 2.3 bushels per acre, or a 3.2%, more than "pure" single varieties.
Christina Cowger, plant pathologist with the USDA Agricultural Research Service, conducted the study in the ARS Plant Sciences Research Unit in Raleigh, N.C.
Cowger developed 13 blends from eight pure wheat varieties, matching complementary features. Each blend was made with equal numbers of seeds of each variety used. She planted the 13 wheat mixtures, and eight pure stands, in three different North Carolina counties representative of the state's sandy, organic and clay soil environments. All 21 entries were planted in a two-year, replicated experiment in each of the three representative locations.
Cowger studied the blends' response to powdery mildew, leaf rust, soilborne viruses and other diseases. She also evaluated yield, test weight, and quality factors at all three test sites. For the analysis, Cowger averaged the data over the 2-year period of 2005 and 2006.