Diallel analysis of cultivar mixtures in winter wheat

Cultivar mixtures have been suggested as a means to achieve increased crop productivity. By choosing cultivars that complement each other for performa nce of important traits, mixtures could be formulated to meet specific prod uction requirements. The objective of this study was to evaluate the perfor mance of wheat mixtures and their pure line component cultivars across a wi de range of environmental conditions. Six winter wheat (Triticum aestivum L .) pure line cultivars and the 15 mixtures obtained by mixing seed of pairs of cultivars in equal proportions were evaluated in 33 environments in eas tern Washington. Averaged across all environments, mixtures were 1.5% highe r yielding than the mean yield of their pure line cultivar components. Ther e was no difference in protein between mixtures and pure line cultivars. Fo r both grain yield and protein, performance in mixtures was highly correlat ed with the average of the two component pure lines. Diallel analysis of mi xing ability, analogous to genetic analysis of combining ability, demonstra ted that pure lines differed in their ability to determine both grain yield and protein in mixtures. The ability to predict mixture performance based on pure line performance, together with the potential for above average gra in yield, suggested that mixtures can be formulated to achieve specific pro duction requirements.