Breeding Wheat for Improved Milling and Baking Quality

Abstract

The molecular determinants of flour functionality and the targeted end-uses for flour define the methods used for improving wheat (Triticum aestivum L.) quality. We review major biochemical systems (gluten, grain hardness, starch, pentosans, lipids, and pigments) affecting wheat milling and baking quality. In early segregating generations (Fj to F₄), breeding programs select for the basic criteria that define a market class (e.g., grain hardness, color, kernel shape, and gluten strength). When desired and possible, improvement of highly heritable traits (e.g., PPO, GBSS mutations, and glutenin sub-units) in early generations is practiced through selection for desired seed or molecular phenotype. In advanced generations (F₅ to cultivar release), bake tests and rheological measures identify breeding lines fitting the subtle characteristics of a market class. Breeding programs favor rapid measures of end-use quality to rank breeding lines for relative end-use quality rather than time consuming protocols that would precisely measure the rheology of flour. Integration of genetic, biochemical, and rheological factors with breeding goals and realistic selection protocols results in the improvement of end-use quality for new cultivars of wheat.