Development of a Functional Marker for Marker-Assisted Selection of 'Orange Lemma' Mutants to Improve Feed Quality in Barley

Full text: Barley is a major cereal crop for feed consumed by a wide range of animals including cows, pigs and poultry as green forage, hay, silage or seed. Multiple mutations exist in barley that can be exploited to develop specific forage barley varieties. Barley 'orange lemma' (rob1) mutants show similar phenotypic characteristics compared to mutants in maize or even trees such as poplar that have reduced lignin content. A range of barley 'orange lemma' cultivars exist either as natural variants or induced using chemical and physical mutagenesis techniques. Most genes in the lignin biosynthesis pathway have been well characterized opening perspectives to develop a functional marker for orange lemma using a candidate gene approach. Here we describe the molecular and genetic characterization of orange lemma in different spring barley accessions. Candidate causative mutations underlying the orange lemma phenotype were identified. An allele-specific assay was developed for rob1 in the Bowman genetic background. Genetic and phenotypic analysis of the F1 derived from the rob1 mutant and its parental line showed that orange lemma is a monofactorial recessive trait. Using a segregating F2 population, trait and marker linkage could be demonstrated. Experiments have been initiated to validate the marker assay in additional barley genetic backgrounds to enable marker-assisted backcrossing of rob1 for feed barley improvement. (author)