International Database for Barley Genes and Barley Genetic Stocks

BGS 473, Compositum 1, com1

BGN  47:135
Stock number: BGS 473
Locus name: Compositum 1
Locus symbol: com1

Previous nomenclature and gene symbolization:

Laxatum-270 = lax-270 (5, 7, 9).
Short-haired, inflorescent rachilla = si (7).
Branching, inflorescent rachilla = bir1a (8).
Compositum = com1a (9, 10, 11).


Monofactorial recessive (7, 8, 9).
Located in chromosome 5HL (11, 12); com1.a is near the srh1 (short rachilla hair 1) locus (12); com1.a is between the ert-n (erectoides-n) and the lax-a (laxatum-a) loci (11), but widely different estimates of their distance from the srh1 (short rachilla hair 1) locus are reported (6, 11); com1.a is associated with SNP markers 1_0974 to 1_0641 (positions 41.99 to 108.33 cM) in 5H of the Bowman backcross-derived line BW189 (1); com1.l is associated with SNP markers 3_0745 to 1_0641 (positions 99.51 to 108.33 cM) in 5HL of the Bowman backcross-derived line BW605 (1), likely in 5H bin 06.


The spike is branched from the rachis of the bottom 1 to 10 spikelets. Awns, which vary from normal to thread-like, and protruding branches are bent in various directions because of "packing" problems in the boot (7). More spike branches develop from rachis nodes under favorable environmental conditions. Plants of Bowman backcross-derived lines BW189, BW190, and BW605 had slightly lower kernel weight and test weights compared to Bowman. The average kernel width was slightly reduced (3).

Origin of mutant:

An ethyl methanesulfonate and neutron induced mutant in Foma (NGB 14659, CIho 11333) (2, 7).

Mutational events:

com1.a (lax.270, NGB 116495, GSHO 1702), com1.b (lax.271, NGB 116496), com1.c (lax.272, NGB 116497), com1.d (lax.206, NGB 116433), com1.e (lax.213, NGB 116442) in Foma (NGB 14659, CIho 11333) (9); com1.i (lax.296, NGB 116520, GSHO 1699) in Foma (3, 9); com1.l (mul.c, Mut. 2227, GSHO 2412) in Donaria (PI 161974) (3, 13).

Mutant used for description and seed stocks:

com1.a (NGB 116495, GSHO 1702) in Foma; com1.a in Bowman (PI 483237)*6 (GSHO 2098); com1.a in Bowman*7 (BW189, NGB 22021); com1.i (NGB 116520, GSHO 1699) in Foma; com1.i in Bowman*3 (GSHO 2232); com1.i in Bowman*5 (BW190, NGB 22022); com1.l (mul.c) in Donaria (GSHO 2412); com1.l in Bowman*6 (GSHO2312); com1.l in Bowman*7 (BW605, NGB 22171).


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. Ehrenberg, L., Å. Gustafsson, and U. Lundqvist. 1959. The mutagenic effects of ionizing radiations and reactive ethylene derivatives in barley. Hereditas 45:351-368.
3. Franckowiak, J.D. (Unpublished).
4. Franckowiak, J.D., B.P. Forster, U. Lundqvist, J. Lyon, I. Pitkethly, and W.T.B. Thomas. 2010. Developmental mutants as a guide to the barley phytomer. pp. 46-60. In: S. Ceccarelli and S. Grando (eds), Proc. 10th International Barley Genetics Symposium, 5-10 April 2008, Alexandria Egypt. ICARDA, PO Box 5466, Aleppo, Syria.
5. Gustafsson, Å., A. Hagberg, U. Lundqvist, and G. Persson. 1969. A proposed system of symbols for the collection of barley mutants at Svalöv. Hereditas 62:409-414.
6. Jensen, J. 1981. Construction of a barley chromosome 7 linkage map. p. 927-939. In M.J.C. Asher, R.P. Ellis, A.M. Hayter, and R.N.H. Whitehouse (eds.) Barley Genetics IV. Proc. Fourth Int. Barley Genet. Symp., Edinburgh. Edinburgh Univ. Press, Edinburgh.
7. Larsson, H.E.B. 1981. Branching spike mutants from two loci in two-row barley. Barley Genet. Newsl. 11:25-28.
8. Larsson, H.E.B. 1983. New data about a gene for branching inflorescent rachilla located on barley chromosome 7. Barley Genet. Newsl. 13:82-83.
9. Larsson, H.E.B. 1985. Morphological analysis of laxatum barley mutants. Hereditas 103:239-253.
10. Larsson, H.E.B. 1985. Genetic analysis of laxatum barley mutants. Hereditas 103:255-267.
11. Larsson, H.E.B. 1985. Linkage studies with genetic markers and some laxatum barley mutants. Hereditas 103:269-279.
12. Persson, G. 1969. An attempt to find suitable genetic markers for dense ear loci in barley I. Hereditas 62:25-96.
13. Scholz, F., and O. Lehmann. 1958. Die Gaterslebener Mutanten der Saatgerste in Beziehung zur Formenmannigfaltigkeit der Art Hordeum vulgare L.s.l.I. Kulturpflanze 6:123-166.


H.E.B. Larsson and U. Lundqvist. 1986. Barley Genet. Newsl. 16:56.


U. Lundqvist and J.D. Franckowiak. 1997. Barley Genet. Newsl. 26:420.
U. Lundqvist and J. D. Franckowiak. 2010. Barley Genet. Newsl. 40:118-119.
U. Lundqvist and J.D. Franckowiak. 2017. Barley Genet. Newsl. 47:135-136.