Winter wheat blends (mixtures) produce a yield advantage in north carolina
Seed mixtures, or blends, of small grain cultivars are unknown in eastern U.S. wheat production, where numerous diseases and abiotic stresses often reduce yield and quality. In 2004–2005 and 2005–2006, a field experiment was conducted at Kinston, Plymouth, and Salisbury, NC, to compare performance of eight soft red winter wheat (Triticum aestivum L.) cultivars having a range of maturities with that of 13 blends, each consisting of equal proportions of two or three of the cultivars. The blends were composed to have complementary disease resistance traits. Disease pressure was at most moderate in any environment. Blends significantly outyielded the means of their respective components (midcomponents) in Plymouth in 2005 (P = 0.042) and across all environments (P = 0.039), with a mean overall blend advantage of 0.13 Mg ha–1. Averaged across environments, two blends significantly outyielded their midcomponents (P 0.011). Yield stability of blends exceeded that of pure cultivars by the stability variance model and principal component analysis. In general, blends did not differ significantly from midcomponents for test weight (P = 0.37), protein content (P = 0.10), hardness (P = 0.68), or falling number (sprouting tolerance, P = 0.89), but seed diameter nonuniformity of blends exceeded that of midcomponents (P = 0.0002). Wheat blends may offer a small yield advantage to North Carolina growers even in the absence of severe disease.