International Database for Barley Genes and Barley Genetic Stocks

BGS 327, Extra floret-b, flo-b

BGN  45:121
Stock number: BGS 327
Locus name: Extra floret-b
Locus symbol: flo-b

Revised locus symbol:

The flo-b.3 mutant is likely an allele at the flo-a (extra floret-a) locus based similar phenotypic expression (2) and retained SNP markers in 6H of the Bowman backcross-derived line (BW368) (1). It is recommended that the mutant be renamed flo-a.3. See BGS 182 for more information on the alleles at the flo-a locus.

Previous nomenclature and gene symbolization:



Monofactorial recessive (3, 4).
Located in chromosome 6HL (1); flo-b.3 is associated with SNP markers 2_0746 to 1-1246 (positions 125.86 to 134.55 cM) in 6H bin 08 of the Bowman backcross-derived line BW368 (1); likely in 6H bins 07 or 08.


Extra floral bracts develop occasionally at the base of the central spikelet on the abaxial side. Formation of the extra floral bracts is most common in the central portion of the spike, but rarely will the floral bracts form another spikelet (2, 4). Except for the occasional development of a floral bract below the central spikelet, the Bowman backcross-derived lines for presumed mutants at the flo-a locus, BW367, BW368, and BW369, were phenotypically similar to Bowman (2).

Origin of mutant:

An ethylene imine induced mutant in Foma (NGB 14659, CIho 11333) (4).

Mutational events:

flo-b.3 (NGB 114273, GSHO 1742) in Foma (NGB 14659, CIho 11333) (4).

Mutant used for description and seed stocks:

flo-b.3 (NGB 114275, GSHO1742) in Foma; flo-b.3 in Bowman (PI 483237)*6 (GSHO 2128, BW368, NGB 20607). [The flo-b.3 mutant is likely an allele at the flo-a locus in 6HL (1, 2)].


1. Druka, A., J. Franckowiak, U. Lundqvist, N. Bonar, J. Alexander, K. Houston, S. Radovic, F. Shahinnia, V. Vendrarnin, M. Morgante, N. Stein, and R. Waugh. 2011. Genetic dissection of barley morphology and development. Plant Physiol. 155:617-627.
2. Franckowiak, J.D. 1995. Notes on linkage drag in Bowman backcross derived lines of spring barley. Barley Genet. Newsl. 24:63-70.
3. 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.
4. Lundqvist, U. (Unpublished).


U. Lundqvist and J.D. Franckowiak. 1997. Barley Genet. Newsl. 26:275.
U. Lundqvist and J.D. Franckowiak. 2015. Barley Genet. Newsl. 45:121.