International Database for Barley Genes and Barley Genetic Stocks

BGS 6, Six-rowed spike 1, vrs1

BGN  37:192
Stock number: BGS 6
Locus name: Six-rowed spike 1
Locus symbol: vrs1

Previous nomenclature and gene symbolization:

Two-row vs six-row = Zz (21).
Six-row vs two-row = Aa (6).
Two-rowed = D (17).
Six-row vs two-row = Vv (3).
Six-row vs two-row (distichon) vs two-row (deficiens) = A, as, af (8).
Reduced lateral spikelet appendage on the lemma = lr (9).
Allelic series v, Vd, V, and Vt (22).
Hexastichon mutants = hex-v (5, 6).
Intermedium spike-d = Int-d (4).
Reduced lateral spikelet appendage on the lemma = vlr (19).
The vrs1 DNA sequence identified as HvHox1 (10).


A multiple allelic series, incomplete dominant allele interactions based on the size and shape of lateral spikelets (1, 19, 22).
Located in chromosome 2HL (3, 6, 12, 14); about 30.5 cM distal from the eog1 (elongated outer glume 1) locus (18), in 2H bin 09 and in a 0.90-cM interval between markers cMWG699 and MWG865 (11).


Alleles at this complex locus modify development of the lateral spikelets and the associated lemma awn. The vrs1.a allele (v gene) is present in most six-rowed cultivars and produces well-developed lateral spikelets (6). Based on phylogenetic analysis of the six-rowed cultivars, the six-rowed gene originated independently at least three times (vrs1.a1, vrs1.a2, and vrs1.a3) from different wild type (Vrs1.b) alleles (10). The lemma awn of lateral spikelets will vary from 3/4 to nearly as long as those of central spikelets, depending upon alleles present at other loci. The Vrs1.b allele (V gene, distichon) is present in many two-rowed cultivars and reduces lateral spikelets to sterile bracts with a rounded tip. The Vrs1.t allele (Vt gene, deficiens) causes an extreme reduction in the size of lateral spikelets. The lr or vlr (vrs1.c) gene in Nudihaxtoni and Bozu types will not recombine with the vrs1.a allele (12, 19) and produces phenotypes similar to the Vrs1.d allele (Vd gene) of Svanhals (22). The series of induced mutants in two-rowed barley called hex-v and Int-d mutants differ in the size of lateral spikelets, but they interact with the vrs1.a allele as incomplete dominants (5). Many heterozygous combinations with vrs1.a have a pointed tip on the lemma of sterile lateral spikelets. Alleles at the int-c (intermedium spike-c) locus modify lateral size in the presence of vrs1.a, Vrs1.b, and Vrs1.d, but not when Vrs1.t is present (22). Multiple origins of vrs1 alleles in six-rowed barley have been confirmed by molecular analysis (20). Komatsuda et al. (10) found that expression of the Vrs1 gene was strictly localized in the lateral-spikelet primordia of immature spikes and suggested that the VRS1 protein suppresses development of lateral spikelets.

Origin of mutant:

Natural occurrence in six-rowed barley and induced frequently by mutagenic agents (10, 14).

Mutational events:

vrs1.a1 in most six-rowed cultivars (1, 10, 22); vrs1.a2 in Dissa and Valenci (10), vrs1.a3 in Natsudaikon Mugi (OUK735) (10), Vrs1.b in wild barley (10), Vrs1.b2 in Pamella Blue (OUH630) (10), Vrs1.b3 in Bonus (NGB 14657, PI 189763) (10), Vrs1.t in a few two-rowed cultivars (10, 22); vrs1.c or lr in Nudihaxtoni (PI 32368) (12, 19); Vrs1.d in Svanhals (PI 5474) (22); 23 induced mutants from programs in Belgium, Germany, and Hungary (2); hex-v.3 (NGB 115545), -v.4 (NGB 115546), -v.6 (NGB 115547), -v.7 (NGB115548), -v.8 (NGB 115549), -v.9 (NGB 115550), -v.10 (NGB 115551), -v.11 (NGB 115552), -v.12 (NGB 115553), -v.18 (NGB 115559), -v.44 (NGB 115581), -v.45 (NGB 115582 ), -v.46 (NGB 115583 ), -v.47 (NGB 115584), -v.48 (NGB 115585), in Bonus, -v.13 (NGB 115554), -v.14 (NGB 115555), -v.15 (NGB 115556), -v.16 (NGB 115557), -v.17 (NGB 115558), -v.19 (NGB 115560), -v.21 (NGB 115562), -v.22 (NGB 115563), -v.23 (NGB 115564), -v.24 (NGB 115565), -v.25 (NGB 115566), -v.26 (NGB 115567), -v.27 (NGB 115568), -v.28 (NGB 115569), -v.29 (NGB 115570), -v.30 (NGB 115571), -v.31 (NGB 115572), -v.35 (NGB 115574) in Foma (NGB 14659, CIho 11333), -v.20 (NGB 115561) in Ingrid (NGB 2671, CIho 10083), -v.33 (NGB 115573), -v.36 (NGB 115575), -v.38 (NGB 115576), -v.39 (NGB 115577), -v.41 (NGB 115578), -v.42 (NGB 115579), -v.43 (NGB 115580) in Kristina (NGB 14661, NGB 1500) (5, 14); hex-v.49 (NGB 115586) in Bonus, -v.50 (NGB 115587), -v.51 (NGB 115588) in Sv 79353, -v.52 (NGB 119353) in Golf (NGB 1520, PI 488529) (13); Int-d.11 (NGB 115429), -d.12 (NGB 115430), -d.22 (NGB 115440), -d.24 (NGB 115442), -d.28 (NGB 115446), -d.36 (NGB 115454) in Foma, -d.40 (NGB 115458), -d.41 (NGB 115459), -d.50 (NGB 115468), -d.57 (NGB 115475), -d.67 (NGB 115485), -d.68 (NGB 115486), -d.69 (NGB 115487) in Kristina (5, 15); Int-d.73 (NGB 115491), -d.80 (NGB 115498), -d.82 (NGB 115500) in Bonus, -d.93 (NGB 115511), -d.94 (NGB 115512), -d.96 (NGB 115514), -d.97 (NGB 115515), -d.100 (NGB 115518) in Hege (NGB 13692) (13); vrs1.o (v1b) in New Golden (16).

Mutant used for description and seed stocks:

vrs1.a in Trebi (PI 537442, GSHO 196); vrs1.a in Bonneville (CIho 7248) (7); vrs1.a from Glenn (CIho 15769) in Bowman (PI 483237)*8 (GSHO 1907, BW898, NGB 22330); Int-d.12 in Bowman*7 (GSHO 1910, BW422, NGB 20655).


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