Contribution of genetic resources to grain storage protein composition and wheat quality

The technological quality of wheat flour is defined by a range of dough characteristics relevant to the breadmaking processes and practices of individual countries and for particular products. The influence of storage protein diversity on wheat quality has been widely documented in the last three decades. The present chapter focuses on several aspects of wheat quality that merit more attention. The huge genetic diversity of wheat storage proteins means that all the possible allelic combinations and their interactions are too numerous to be tested in terms of their influence on the major quality parameters. However it is still relevant to describe the variation in rheological and viscoelastic properties of gluten in relation to its component proteins, glutenin and gliadin. Although gluten plays a major role in determining the properties of dough, the abundance of the two major storage protein fractions does not solely explain the observed variation in those properties. We therefore examine the influence of some genetic factors, including those affecting the protein composition, on the variation in the glutenin polymer sizes. Some examples will be given to illustrate how end-use quality can be improved by taking advantage of the available genetic resources in parallel with molecular genome analyses with the dual aim of widening the scope of characteristics that can be harnessed in breeding and ensuring consistent wheat quality in changing agro-climatic situations. The known alleles of the major genes are highlighted in the context of the challenges that the research community is facing regarding wheat allele nomenclature, exchange of gene bank material and the numerous quality attributes of interest. Finally, important research objectives are proposed for breeding future wheats with grain protein quality and technological properties tailored for different food products.