|Vander wal, L.|
Submitted to: Journal of Heredity
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/20/2005
Publication Date: 10/26/2005
Citation: Dahleen, L.S., Vander Wal, L.J., Franckowiak, J.D. 2005. Characterization and molecular mapping of genes determining semidwarfism in barley. Journal of Heredity 96:654-662. Interpretive Summary: The semidwarf trait in barley is desirable because reduced height and stronger stems help plants remain upright throughout the growing season, increasing yield for growers. Semidwarf malting and feed barley varieties have been used extensively in Asia and Europe, but not in the US because the semidwarf gene used here has negative effects on yield and quality. We have evaluated 27 semidwarf barley mutants and located the semidwarf genes in specific barley chromosomes. While many of them have undesirable traits like reduced kernel weight, several had acceptable yields and other traits. This information can be used to select the best semidwarf mutants for use in breeding new barley semidwarf varieties.
Technical Abstract: We characterized 27 brachytic (brh) semidwarf mutants in barley (Hordeum vulgare) and located the genes on barley chromosome linkage maps. All brachytic genes were transferred into the two-rowed cultivar ‘Bowman’ by backcrossing 4-7 times, and selecting for semidwarf plants. The brachytic lines were evaluated for ten phenotypic traits: height, awn, peduncle, rachis internode length, leaf length and width, lodging, yield, number of kernels per spike and kernel weight. We intercrossed the lines to determine which mutants were at independent loci and which were alleles at the same locus. F2 populations from 18 brh semidwarfs were constructed for genetic mapping using simple sequence repeat (SSR) markers. The brachytic semidwarf near-isogenic lines were significantly shorter than their normal counterparts and most had lower yields (16/27), shorter awns (26/27), peduncles (26/27), rachis internodes (24/27), and reduced kernel weight (22/27). Twelve of the lines had shorter penultimate leaves and fifteen had reduced lodging. Four lines had increased kernels per spike while one had fewer kernels per spike. The allelism tests and the mapping comparisons indicated that the 27 semidwarfs comprise 18 independent genetic loci. SSR mapping placed these loci in five of the seven barley chromosomes.