QTL for Malting Quality - a 25 Piece Puzzle

Abstract

Over the past decade, great progress has been made in identifying and characterising at least 25 QTL associated with the key malting quality parameters of malt extract, diastatic power and cell and protein modification. Does this knowledge greatly enhance the barley breeders efforts to breed better malting barley varieties faster? This paper will examine marker-assisted selection for malt quality in a general sense, but more specifically in several current breeding projects including attempts to convert a feed barley variety cv. Keel (with low malt extract, low diastatic power and high wort -glucan) to a malting barley through marker assisted introgression of key QTL from 3 donor parents with excellent malting quality. Knowledge of repulsion phase linkage and pleiotropic effects of key QTL will be described and strategies for overcoming these difficulties discussed. Cases to be presented include the Harrington high diastatic power sprouting propensity locus on 5HL and the thin husk high skinning (peeling) high malt extract locus on 2HS from Haruna nijo.