Chapter 10 Genetic diversity for quantitatively inherited agronomic and malting quality traits

Abstract

This chapter reviews diversity in agronomic traits, diversity in malting quality traits, and the current status of Quantitative Trait Loci (QTL) analysis in barley and the application of QTL tools to the analysis of genetic diversity in barley and crop improvement. Agronomic and quality traits were undoubtedly key issues for the domesticators of barley. Crop productivity would clearly have been an attribute of key interest, and the selection of shattering-resistant mutants probably led to a quantum leap in yield. Because barley has been used both as a food and as a principal ingredient of fermented beverages from the earliest times, there may well have been conscious selection for end-use properties. The selection of hull-less mutants in areas of the world where barley was a principal foodstuff underscores the importance of end-use properties in domestication. The malting and brewing properties of wild barley accessions and landraces have not been welldescribed and are, in fact, extremely difficult to measure. Plant breeding efforts are directed primarily at traits exhibiting quantitative variation. Breeders and geneticists were now able to collaborate in developing and testing hypotheses regarding the number, location, effect, and interactions of genes influencing quantitative traits.