Mutations in the gene of the Gα subunit of the heterotrimeric G protein are the cause for the semi-dwarf phenotype in barley and applicable for practical breeding.

BACKGROUND

Short-culm mutants have been widely used in breeding programs to increase lodging resistance. In barley ( L.), several hundreds of short-culm mutants have been isolated over the years. The objective of the present study was to identify the () semi-dwarfing gene and to test its effect on yield and malting quality.

RESULTS

Double-haploid lines generated through a cross between a mutant and the European elite malting cultivar Quench, showed good malting quality but a decrease in yield. Especially the activities of the starch degrading enzymes β-amylase and free limit dextrinase were high. A syntenic approach comparing markers in barley to those in rice ( L.), sorghum ( Moench) and brachypodium ( P. Beauv) helped us to identify as an orthologue of rice encoding the Gα subunit of a heterotrimeric G protein. We demonstrated that is allelic to . Sixteen different mutant alleles were described at the DNA level.

CONCLUSIONS

Mutants in the locus are deficient in the Gα subunit of a heterotrimeric G protein, which shows that heterotrimeric G proteins are important regulators of culm length in barley. Mutant alleles do not have any major negative effects on malting quality.