BGS 45, Semidwarf 4, sdw4

Culm length QTL on 7H = qCUL.ak-7H (4).

Monofactorial recessive (3, 7, 8).
Location in chromosome 7HL (4); sdw4.ba is about 1.2 cM from codominant STS marker ABG608 in bin 11 (3, 4); sdw4.ba is near DArT marker bPb-2328 in 7HL (6); sdw4.ba is associated with SNP markers 1_1243 to 2_1363 (positions 167.56 to 198.70 cM) in 7H bins 10 to 12 of the Bowman backcross-derived line BW831 (1); likely in 7H bin 11.

Semidwarf 4 (sdw4) is a monofactorial recessive that reduces culm length by about 20 to 30% ( 4, 6) by affecting the length of the 3rd and 4th culm internodes proportional more than the upper internodes (3, 4). The sdw4 gene was associated with reduced lodging (4). Combining sdw4 with uzu1 (uzu 1) further reduced plant height to less than half normal (3). In the Bowman backcross-derived line for sdw4.ba (BW831), plants were shorter, but the culms were slightly more robust and the flag leaves were larger than those of Bowman. Delayed heading was observed in plants with the sdw4.ba gene in some genetic backgrounds (2). The sdw4.ba mutation in China was reported to have originated as dwarf mutant (68-142) induced in the late 1960s by gamma-rays in the Chinese landrace Zhenongguangmangerleng (7). The first cultivar containing this mutant was Zhepi 1, released in 1978 by the Zhejiang Academy of Agricultural Science (7). Most cultivars now grown in the lower valley of Yangtze River were selected from crosses to Zhepi 1 (7).

A gamma-ray induced mutant in the Chinese landrace Zhenongguangmangerleng (7); a spontaneous variant in the Japanese cultivar Kanto Nakate Gold (OUJ 518) released in 1953 (4), both parents of Kanto Nakate Gold, Shikoku (OUJ 546) and Golden Melon (OUJ808. PI 263410) are tall cultivars (4, 5).

sdw4,ba (68-142) in Zhenongguangmangerleng (7), sdw4.ba in the Japanese cultivar Kanto Nakate Gold (OUJ 518, PI383933) (4). Based on morphological traits and chromosomal location of mutant, both mutational events are very similar (2).

sdw4.ba in Zhepi 1 and Zhenongda 7; sdw4.ba in Kanto Nakate Gold (OUJ 518; PI 383933), sdw4.ba from Zhenongda 7 in Bowman*2 (BW831, NGB 22268).

1. Druka, A., J. Franckowiak, U. Lundqvist, N. Bonar, J. Alexander, K. Houston, S. Radovic, F. Shahinnia, V. Vendramin, M. Morgante, N. Stein, and R. Waugh. 2011. Genetic dissection of barley morphology and development. Plant Physiol. 155:617-627.
2. Franckowiak, J.D. (Unpublished).
3. Sameri, M., S. Nakamura, S.K. Nair, K. Takeda, and T. Komatsuda. 2009. A quantitative trait locus for reduced culm internode length in barley segregates as a Mendelian gene. Theor. Appl. Genet. 118:643-652.
4. Sameri, M., K. Takeda, and T. Komatsuda. 2006. Quantitative trait loci controlling agronomic traits in recombinant inbred lines from a cross of oriental- and occidental-type barley cultivars. Breed. Sci. 56:243-252.
5. Takahashi, R., S. Yasuda, J. Hayashi, T. Fukuyama, I, Moriya, and T. Konishi. 1983. Catalogue of barley germplasm preserved in Okayama University. Inst. Agr. Biol. Sci., Okayama Univ., Kurashiki, Japan. 217 p.
6. Yu, G.T., R.D. Horsley, B. Zhang, and J.D. Franckowiak. 2010. A new semi-dwarfing gene identified by molecular mapping of quantitative trait loci in barley. Theor. Appl. Genet. 120:853-861.
7. Zhang, J., and W. Zhang. 2003. Tracing sources of dwarfing genes in barley breeding in China. Euphytica 131:285-292.
8. Zhang, J., L. Zhen, and C.H. Zhang. 2006. Analysis on the dwarfing genes in Zhepi 1 and Aizao 3: two dwarfing gene donors in barley breeding in China. Agric. Sci. China 5:643-647.

J.D. Franckowiak and G.T. Yu. 2011. Barley Genet. Newsl. 41:80-81.

J.D. Franckowiak. 2016. Barley Genet. Newsl. 46:51-52.