International Database for Barley Genes and Barley Genetic Stocks
BGS 547, Intermedium spike-m, int-m
Stock number: BGS 547
Locus name: Intermedium spike-m
Locus symbol: int-m
Previous nomenclature and gene symbolization:
Monofactorial recessive (5).
Located in chromosome 5HL (2); int-m.85 is associated with SNP markers 2_0988 to 2_1138 (positions 247.08 to 274.74 cM) in 5H bins 13 to 14 of the Bowman backcross-derived line BW429 (2); int-m.la is associated with SNP markers 2_0571 to 1_1249 (positions 69.76 to 109.27 cM) in 5H bins 04 to 06 and with SNP markers 2_1177 to 1_0869 (positions 203.85 to 264.33 cM) in 5H bins 11 to 13 of the Bowman backcross-derived line BW430 (2), likely in 5H bin 13.
The spike is very short and has irregular rachis internode lengths. Lateral spikelets are enlarged and pointed, but they do not set seed. Spikelet density at the base of the spike is increased (5). Tillering of int-m plants is increased and heading is slightly earlier (5). Rachis internodes at the tip of the spike are very short, and the spike appears to have two or three fused or fascinated terminal spikelets (1, 3). Plants of the Bowman backcross-derived line for int-m.85, BW429, had more tillers, 13 vs. 26 (1). Combining the int-m.85 and cul2.b (uniculm 2) mutants produced uniculm plants having long spikes with fused or fascinated terminal spikelets (1). Spikes of the Bowman backcross-derived line for int-m.85, BW430, had slightly less than half as many kernels as Bowman spikes. The shorter spikes caused the awns of BW430 to extend 3 to 5 cm more beyond the upper most spikelet. Kernel of BW430 were 10 to 15% lighter than Bowman kernels. Grain yields of BW430 were about 1/3 of those for Bowman (2).
Origin of mutant:
A sodium azide induced mutant in Bonus (NGB14657, PI 189763) (4).
int-m.85 (NGB 115503, GSHO 1772) in Bonus (NGB14657, PI 189763) (4); int-m.la (GSHO 1773) in Lamont (PI 512036) (3).
Mutant used for description and seed stocks:
int-m.85 (NGB 115503, GSHO 1772) in Bonus; int-m.85 in Bowman (PI 483237)*7 (GSHO 2273, BW429, NGB 20661); int-m.la from Lamont in Bowman (PI 483237)*5 (GSHO 2274, BW430, NGB 20662).
1. Babb, S., and G.J. Muehlbauer. 2003. Genetic and morphological characterization of the barley uniculm 2 (cul2) mutant. Theor. Appl. Genet. 106:846-857.
2. 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.
3. Franckowiak, J.D. (Unpublished).
4. Lundqvist, U. (Unpublished).
5. Lundqvist, U., and A. Lundqvist. 1988. Induced intermedium mutants in barley: origin, morphology and inheritance. Hereditas 108:13-26.
U. Lundqvist and J.D. Franckowiak. 1997. Barley Genet. Newsl. 26:473.
U. Lundqvist and J.D. Franckowiak. 2007. Barley Genet. Newsl. 37:280.
U. Lundqvist and J.D. Franckowiak. 2014. Barley Genet. Newsl. 44:181-182.