Identification of Mutations in Genes Regulating Culm Length in Malting Barley

Sammanfattning: Lodging, the tendency in barley to lie down on the ground when exposed to hail and heavy fertilising, is one of the most important traits that barley breeding is trying to remove from the barley cultivars. This may be an even greater challenge when future climate changes may lead to more extreme weather leading to more severe storms with heavy rain and hail. In this project, 8 breviaristatum (ari)-mutants have been sequenced for mutations in three different genes Brassinosteorid-6 oxidase (HvBRD), Diminuto (HVDIM) and Brassinosteroid-insensitive1 (HvBRI1). These genes are involved in brassinosteroid biosynthesis and signalling. HvBRD and HvDIM encode enzymes taking part in the biosynthesis of brassinosteroids while HvBRI1 encodes the brassinosteroid receptor. Brassinosteroids are plant hormones, which among other things stimulate cell division and elongation. These genes regulate the length of the barley’s culm and a mutation in the genes leads to a shorter culm, a semi-dwarf phenotype, which is more tolerant against lodging. In 5 ari-mutants the mutation could be identified and these mutations can be used in marker-assisted barley breeding programs. These findings can be an important tool enabling more efficient barley breeding, which will be important in the future with predicted more extreme weather. F2-crosses between brassinosteroid mutants, with known mutation, and the arimutants sequenced in this project were also studied. A couple of the individuals that showed severe dwarf phenotype were sequenced in search of being homozygous for the mutations inherited from both parent lines.