International Database for Barley Genes and Barley Genetic Stocks

BGS 202, Third outer glume 1, trd1

BGN  46:65
Stock number: BGS 202
Locus name: Third outer glume 1
Locus symbol: trd1

Previous nomenclature and gene symbolization:

Third glume = t (7).
Bracteate (19).
Bracteatum-c = bra-c (4, 14).


Monofactorial recessive (7, 8, 10, 12).
Located in chromosome 1HL (7, 8, 11, 12); trd1.b is about 16.0 cM distal from the Blp1 (Black lemma and pericarp 1) locus (7, 8, 12); trd1.a is about 11.4 cM proximal from the eam8 (early maturity 8) locus (13); trd1.a is associated with SNP markers 2_0383 to 2_0840 (positions 192.78 to 202.26 cM) in 1H bins 13 to 14 of the Bowman backcross-derived line BW880 (2); bra-c.1 is associated with SNP markers 1_0041 to 2_0772 (positions 199.04 to 206.07 cM) in 1H bin 14 of the Bowman backcross-derived line BW069 (2); trd1.a is between to SNP markers 1_1127 and 2_1105 in1H bin 14 (6).


The characteristic trait of this mutant is the presence of a bract, third outer glume, outside the two empty glumes of the central spikelet. The bract associated with the lowest spikelet is always the largest, embracing in some cases about one-half the spike, and the bracts become progressively smaller toward the tip of the spike (12). The trd1.a mutant is described as a transitional mutant in which suppression of leaf (sheath) development at nodes in the spike is poorly suppressed (1, 11). Basal rachis internodes may be elongated (3, 6). Although allelism tests were not conducted for the first three trd mutants, similar linkage values between the trd and Blp loci are reported (7, 8, 12). Takahashi et al. (12) assumed that they used the same material studied by Miyake and Imai (10). Compared to Bowman, plants of the Bowman backcross-derived lines for trd1.a and bra-c.1, BW880 and BW069, headed 2 to 4 days later and were slightly shorter. Spikes of BW880 and BW069 had 2 to 3 fewer fertile rachis nodes per spike; and their grain .yields were 1/2 to 2/3 that of Bowman (3). The Trd1 locus was identified as the GATA transcription factor, an ortholog of rice Nl1 and maize Tsh1 genes (5).

Origin of mutant:

A spontaneous mutant in Hordeum vulgare var afghanicum found by Vavilov in a black six-rowed accession classified as Hordeum vulgare var. afghanicum (7).

Mutational events:

trd1.a in Hordeum vulgare var. afghanicum (7, 10); trd1.b ((GSHO 227) in Valki (CIho 5478) (8); trd1.c in a Japanese cultivar (10, 12); trd1.d (Mut 1969/61) in Proctor (PI 280420) (5); bra-c.1 (NGB 114303, GSHO 1695) in Bonus (NGB 14657, PI 189763) (4); bra-c.2 (NGB 114304), -c.3 (NGB 114305), -c.4 (NGB 114306), -c.5 (NGB114307) in Bonus, -c.6 (NGB 114308) in Foma (NGB 14659, CIho 11333), -c.8 (NGB 114311) in Kristina (NGB 14661, NGB 1500) (9).

Mutant used for description and seed stocks:

trd1.b (GSHO 227) in Valki; bra-c.1 (NGB 114303, GSHO 1695) in Bonus; trd1.b from R.I. Wolfe's Chromosome 5 Marker Stock in Bowman (PI 483237)*7 (GSHO 2060); trd1.b in Bowman*8 (BW880, NGB 22314); bra-c.1 in Bowman*4 (GSHO 2061); bra-c.1 in Bowman*5 (BW069, NGB 20477).


1. Bossinger, G., W. Rohde W, U. Lundqvist U, and F. Salamini F. 1992. Genetics of barley development: mutant phenotypes and molecular aspects. p. 231-264. In P.R. Shewry (ed.) Barley: Genetics, Biochemistry, Molecular Biology and Biotechnology. CAB International, Oxford.
2. 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.
3. Franckowiak, J.D. (Unpublished).
4. 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.
5. Häuser, H., and G. Fischbeck. 1972. Translocations and genetic analysis of other mutants. Barley Genet. Newsl. 2:28-29.
6. Houston, K., A. Druka, N. Bonar, M. Macaulay, U. Lundqvist, J. Franckowiak, M. Morgante, N. Stein, and R. Waugh. 2012. Analysis of the barley bract suppression gene Trd1. Theor. Appl. Genet. 125:33-45.
7. Ivanova, K.V. 1937. A new character in barley "third outer glume" — Its inheritance and linkage with color of the flowering glumes. Bull. Appl. Bot., Genet., & Pl. Breed. II. 7:339-353.
8. Konzak, C.F. 1953. The third outer glume character in barley. J. Hered. 44:103-104.
9. Lundqvist, U. (Unpublished).
10. Miyake, K., and Y. Imai. 1922. [Genetic studies in barley. 1.] Bot. Mag., Tokyo 36:25-38. [In Japanese.]
11. Pozzi, C., D. di Pietro, G. Halas, C. Roig, and F. Salamini. 2003. Integration of a barley (Hordeum vulgare) molecular linkage map with the position of genetic loci hosting 29 developmental mutants. Heredity 90:390-396.
12. Takahashi, R., J. Yamamoto, S. Yasuda, and Y. Itano. 1953. Inheritance and linkage studies in barley. Ber. Ohara Inst. landw. Forsch. 10:29-52.
13. Takahashi, R., and S. Yasuda. 1971. Genetics of earliness and growth habit in barley. p. 388-408. In R.A. Nilan (ed.) Barley Genetics II. Proc. Second Int. Barley Genet. Symp., Pullman, WA, 1969. Washington State Univ. Press, Pullman.
14. Tsuchiya, T. 1974. Further results of allelism testing in barley. Barley Genet. Newsl. 4:82-85.


T.E. Haus and T. Tsuchiya. 1971. Barley Genet. Newsl. 1:147.


T. Tsuchiya. 1980. Barley Genet. Newsl. 10:121.
J.D. Franckowiak and U. Lundqvist. 1997. Barley Genet. Newsl. 26:207-208.
J.D. Franckowiak and U. Lundqvist. 2016. Barley Genet. Newsl. 46:65-66.