International Database for Barley Genes and Barley Genetic Stocks

BGS 251, Multiflorus 2, mul2

BGN  48:119
Stock number: BGS 251
Locus name: Multiflorus 2
Locus symbol: mul2

Previous nomenclature and gene symbolization:

Multiflorus 2 = mlt2 (5).
The change to mul2 was recommended by Robertson (4).


Monofactorial recessive (5).
Located in chromosome 6HL (3, 5); mul2.b is about 24.2 cM distal from the rob1 (orange lemma 1) locus (3, 5); in the Bowman backcross-derived stock for mul2.b (BW607) only SNP markers associated with the vrs1.a allele were retained, 1_1100 to 2_0340 (positions 135.19 to 138.37 cM) in 2HL bin 09 (1).


Lateral spikelets may have supernumerary florets and occasionally nodal branches appear at random in the spike. The character shows variable expression in some crosses, and only a few spikes may be affected in some plants (5). The trait is expressed only as a malformed rachilla in some lateral spikelets of six-rowed plants in the Bowman backcross-derived line. The rachilla malformation is most pronounced near the middle of the spike and ranges from formation of a fertile spikelet to slight elongation of the rachilla (2). The lack of SNP markers from the donor parent in BW607 other than those associated with vrs1.a (six-rowed spike 1) allele suggests that the mul2.b is likely an unexpressed trait present in Bowman (2).

Origin of mutant:

A betatron induced mutant in Montcalm (CIho 7149) (5).

Mutational events:

mul2.b (Alb Acc 299, GBC326, GSHO 1394) in Montcalm (CIho 7149) (3, 5).

Mutant used for description and seed stocks:

mul2.b (GSHO 1394) in Montcalm (CIho 7149); mul2.b plus vrs1.a in Bowman (PI 483237, NGB 22812)*6 (GSHO 2089); mul2.b plus vrs1.a (six-rowed spike 1) in Bowman*7 (BW 607, NGB 22173). (A six-rowed phenotype is required for expression.)


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 Franckowiak, J.D. (Unpublished).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. Kasha, K.G., D.E. Falk, and A. Ho-Tsai. 1978. Linkage data with genes on chromosome 6. Barley Genet. Newsl. 8:61-65.
4. Robertson, D.W. 1964. New genes in barley with their relation to linkage groups and chromosomes. p. 159-180. In S. Broekhuizen, G. Dantuma, H. Lamberts, and W. Lange (eds.) Barley Genetics I. Proc. First Int. Barley Genet. Symp., Wageningen, 1963. Centre for Agricultural Publications and Documentation, Wageningen.
5. Walker, G.W.R., J. Dietrich, R. Miller, and K. Kasha. 1963. Recent barley mutants and their linkages II. Genetic data for further mutants. Can. J. Genet. Cytol. 5:200-219.


T. Tsuchiya and T.E. Haus. 1971. Barley Genet. Newsl. 1:154.


J.D. Franckowiak. 1997. Barley Genet. Newsl. 26:232.
J.D. Franckowiak. 2018. Barley Genet. Newsl. 48:119.