Coordinator's report: Semidwarf genes
J.D. Franckowiak
Department of Plant Sciences, North Dakota State University
Fargo, ND 58105, U.S.A.

Falk (1995) identified a new dominant gene for dwarfing (Dwf2) as a sector in a doubled haploid plant regenerated from anther culture. Dwarf plants were shown to be heterozygous, and homozygous dominant plants were not observed in any of the subsequent progenies. Heterozygous tillered profusely, but growth was slow and heading was very late. Dwarf plants did not respond to applications of gibberellic acid.

Barau et al. (1993) located the denso or sdw1 (semidwarf 1) locus in the long arm of chromosome 3. Alleles at this locus are used more than other semidwarf genes in barley breeding programs. The relative position of sdw1 on the morphology marker map of chromosome 3 was not determined, but it will be placed likely proximal from the gs2 (glossy sheath 2) locus.

Forty semidwarf barley mutants, most are included in the collection of barley semidwarfs, were placed in the brachytic subgroup and several were assigned gene symbols (Franckowiak, 1995). The genes br.t (DWS1038), br.x (DWS1224), and br.ae (FN53) proved to be alleles at the br1 (brachytic 1) locus and were assigned the allele symbols br1.t, br1.x, and br1.ae, respectively. The gene ari-l (breviaristatum-l) was shown to be allelic at the br2 locus (Franckowiak, 1995). The ari-n (breviaristatum-n) gene should not have been included in the list of brachytic mutants because the stock identified as DWS1037 contained an ari-m allele instead of an allele at the ari-n locus. The correct seed lot will be available as DWS1037 in the future.

References:

Barau, U.M., K.J. Chambers, W.T.B. Thomas, C.A. Hackett, V. Lea, P. Jack, B.P. Forster, R. Waugh, and W. Powell. 1993. Molecular mapping of genes determining height, time to heading, and growth habit in barley (Hordeum vulgare). Genome 36:1080-1087.

Falk, D.E. 1995. New dominant dwarfing gene (Dwf2) in barley. BGN 24:87-89.

Franckowiak, J.D. 1995. The brachytic class of semidwarf mutants in Barley. BGN 24:56-59.