International Database for Barley Genes and Barley Genetic Stocks
BGS 314, Six-rowed spike 2, vrs2
Stock number: BGS 314
Locus name: Six-rowed spike 2
Locus symbol: vrs2
Previous nomenclature and gene symbolization:
Six-rowed spike 2 = v2 (10).
Intermedium-b = int-b (6, 7, 13).
Monofactorial recessive (4, 5, 6, 8, 12).
Located in chromosome 5HL (10, 11); vrs2.e is over 19.0 cM proximal from the srh1 (short rachilla hair 1) locus (10 11, 12); vrs2.e is associated with SNP markers 2_1421 to 1_0477 (positions 159.51 to 173.49 cM) in 5H bins 09 to 10 of the Bowman backcross-derived line BW901 (1); int-b.3 is near the raw1 (smooth awn 1) locus based on linkage drag (3); int-b.3 is associated with SNP markers 2_0134 to 2_1355 (positions 163.29 to 234.98 cM) in 5H bins 10 to 13 of the Bowman backcross-derived line BW420 (1), likely in 5H bin 10. A high-resolution genetic map of the vrs2 locus was developed using recombinants and barley BACs (13).
The spike appears similar to the ordinary six-rowed spike, but the lateral spikelets on the upper and lower portion of the spike are reduced in size, less fertile, and more or less pedicellated. Lateral spikelets are pointed with reduced awn length or awnless (4, 11, 12). Kernels of the Bowman backcross-derived line for vrs2.e, BW901, were 15 to 20% lighter than kernels of Bowman. BW901 plants exhibited reduced tillering and grain yield was about half that of Bowman (2). Plants of the backcross-derived line for int-b.3, BW420, headed 2 to 3 days earlier than Bowman, but more lodging was observed. The BW420 kernels were slightly longer, but weighed less, 52 vs. 58 mg, compared to those of Bowman. Grain yields of BW420 were 10 to 30% of those recorded for Bowman (3). Late heading and prolonged development of BW901 was reported in Germany (13), but this was not observed in field tests in Australia, England, New Zealand, or the USA (3). During barley inflorescence and shoot development, the gene at the Vrs2 locus encodes for a SHORT INTERNODES (SHI) transcriptional regulator (13).
Origin of mutant:
vrs2.e is an X-ray induced mutant in Svanhals (PI 5474, GSHO 784, OUU032) (10. 12). int-b.3 is a neutron induced mutant in Bonus (NGB 14657, PI 189763) (9).
vrs2.e (Kmut 27, OUM284, GSHO 773) in Svanhals (PI 5474, GSHO 784, OUU032) (12).; int-b.3 (NGB 115421, GSHO 1764), -b.6 (NGB 115424) in Bonus (NGB 14657, PI 189763) (6, 8); int-b.75 (NGB 115493) in Bonus (8); HOR19366 in the Genebank of the Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany. (isolated as spontaneous mutant in a cultivated landrace collection from USA) (13).
Mutant used for description and seed stocks:
vrs2.e (Knut 27, GSHO 773, OUM284) in Svanhals; vrs2.e in Bowman (PI 483237)*4 (GSHO 2111); vrs2.e in Bowman*6 (BW901, NGB 22333); int-b.3 (NGB 115421, GSHO 1764) in Bonus; int-b.3 in Bowman (PI 483237)*6 (GSHO 2129); int-b.3 in Bowman*7 (BW420, NGB 20653).
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2 Franckowiak, J.D. (Unpublished).
3. Franckowiak, J.D. 1995. Notes on linkage drag in Bowman backcross derived lines of spring barley. Barley Genet. Newsl. 24:63-70.
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8. Lundqvist, U. (Unpublished).
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10. Takahashi, R., J. Hayashi, and C. Hirao. 1968. Linkage studies. Barley Newsl. 11:59.
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13. Youssef, H.M., K. Eggert, R. Koppolu, A.M. Alqudah, N. Poursarebani, A. Fazeli, S. Sakuma, A. Tagiri, T. Rutten, G. Govind, U. Lundqvist, A. Graner, T Komatsuda, N. Sreenivasulu, and T. Schnurbusch. 2017. VRS2 regulates hormone-mediated inflorescence patterning in barley. Nat. Genet. 49:157-161.
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U. Lundqvist and J.D. Franckowiak. 2017. Barley Genet. Newsl. 47:113-114.