International Database for Barley Genes and Barley Genetic Stocks

BGS 518, Semidwarf 1, sdw1

BGN  47:168
Stock number: BGS 518
Locus name: Semidwarf 1
Locus symbol: sdw1

Previous nomenclature and gene symbolization:

Denso dwarf = denso (7, 17).
Hordeum vulgare gibberellin 20-oxidase = Hv20ox2 (10, 11, 21).


Monofactorial recessive (7, 19); some F1's are intermediate in height (1, 13).
Location in chromosome 3HL (2, 14); sdw1.d is probably proximal from the gsh2 (glossy sheath 2) locus and near RFLP marker PSR170 (14); sdw1.d is in bin 3H-11 (12); sdw1.d is near RFLP marker R1545 (22); sdw1.d is close to SNP marker 1_0867 (15); sdw1.a is associated with SNP markers 1_0044 to 2_0650 (positions about 190 to 192.00 cM) in 3H bin 12 of the Bowman backcross-derived line BW827 (4); sdw1.d is associated with SNP markers 2_0023 to 1_0821 (positions 169.94 to 190.87 cM) in 3H bins 11 and 12 of the Bowman backcross-derived line BW828 (4), in 3H bin 12.


Plants homozygous for the sdw1.a gene ranged from 10 to 30 cm shorter than normal sibs, with expression partial dependent on environment (1, 18, 20). Spike length was variable, but fully as long as normal barley. The stock used for description of the sdw1.a gene, M21, has the short straw and long spike of the original 'Jotun Mutant' as well as a large culm diameter from its parent 'Vantage' (1, 20). The semidwarf mutants, 'Diamant' and ‘Abed Denso’, are alleles at the sdw1 locus (7, 16). Alleles at the sdw1 locus are associated with semi-prostrate juvenile growth (7, 18), delayed maturity (5, 7, 8, 18, 22), smaller grain size (7), and reduced malt quality (5, 8, 18). The sdw1 mutants are GA sensitive (3, 23). They are very likely mutants in an orthologue of the rice sd1 gene (23), which encodes a GA-oxidase that produces lower levels of GA and reduced levels of cause the dwarf phenotype (9, 17). A gibberellin 20-oxidase gene (Hv20ox2) was identified as the candidate gene for sdw1 (10, 11). The reduced expression of Hv20ox2 increased the number of effective tillers and enhanced grain yield (11, 21). The reduction in Hv20ox2 levels was 4-fold in the sdw1.d mutant and 60-fold in the sdw1.a mutant which causes a reduced endogenous GAs concentration and delayed heading (11). Plants of the Bowman backcross-derived line for sdw1.a, BW827, were 15 to 30% shorter than Bowman, heading was delayed 1 to 3 days,. and spikes had 1 to 2 more kernels in some trials. Kernels of BW827 and BW828 were up to 10% lighter than Bowman kernels in some trials. Grain yields of BW828 were similar to those of Bowman, while those of BW827 were about 85% of the Bowman yields (6). The QTL for sdw1.d co-located with QTL for yield, plant height, development score, hectoliter weight and grain plumpness (11).

Origin of mutant:

An X-ray induced mutant in the Norwegian cultivar Jotun (NGB 466, PI 467357) isolated as Jotun 22 by Knut Mikaelsen (1, 13).

Mutational events:

sdw1.a (66/86, GSHO 1414) in Jotun (NGB 466, PI 467357) (20); sdw1.c (denso) in Abed Denso (PI 361639) (7); sdw1.d (Diamant, PI 330397, PI 467775) in Valticky (PI 268173) (7); sdw1.e (Risø no. 9265) in Abed Bomi (NGB 5096, PI 43371) (7, 9). Some cultivars demonstrated to have the sdw1.a and sdw1.d alleles listed in Xu et al. (21). Note that the denso name was original assigned to the sdw1.c mutant (7), but sdw1.d mutant from Diamant is the only allele present in cultivars described as having the denso semidwarf (21).

Mutant used for description and seed stocks:

sdw1.a in M21 (CIho 15481, GSHO 2513) from the cross Jotun Mutant/Kindred// Vantage (20); sdw1.d in Trumpf (Triumph, PI 548762, GSHO 2465) from Diamant; sdw1.a from a Jotun derivative in Bowman (PI 483237)*7 (GSHO 1978), sdw1.a in Bowman*8 (BW827, NGB 22264); sdw1.d from Trumpf in Bowman*4 (GSHO 1979), sdw1.d in Bowman*5 (BW828, NGB 22265).


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11. Jia, Q., X.Q. Zhang, S. Westcott, S. Broughton, M. Cakir, J. Yang, R. Lance, and C. Li. 2011. Expression level of a gibberellin 20-oxidase gene is associated with multiple agronomic and quality traits in barley. Theor. Appl. Genet. 122:1451-1460.
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20. Rasmusson, D.C., E.E. Banttari, and J.W. Lambert. 1973. Registration of M21 and M22 semidwarf barley. Crop Sci. 13:777
21. Xu, Y., Q. Jia, G. Zhou, X.-Q. Zhang, T. Angessa, S. Broughton, G. Yan, W. Zhang, and C. Li.. 2017. Characterization of the sdw1 semi-dwarf gene in barley. BMC Plant Biology 17:11.
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24. .


D.C. Rasmusson. 1988. Barley Genet. Newsl. 18:87 as BGS 468.


J.D. Franckowiak. 1997. Barley Genet. Newsl. 26:444-445.
J.D. Franckowiak. 2007. Barley Genet. Newsl. 37:277-278.
J.D. Franckowiak. 2011. Barley Genet. Newsl. 41:176-178.
J.D. Franckowiak. 2017. Barley Genet. Newsl. 47:168-170.