International Database for Barley Genes and Barley Genetic Stocks

BGS 21, Reaction to Ustilago nuda 1 (loose smut), Run1

BGN  26:67
Stock number: BGS 21
Locus name: Reaction to Ustilago nuda 1 (loose smut)
Locus symbol: Run1

Previous nomenclature and gene symbolization:

Resistance to Ustilago nuda = Un (3).


Monofactorial dominant (2, 6).
Located in chromosome 7HS (1, 5); Run1.a is about 2.0 cM proximal from the Rpg1 (reaction to Puccinia graminis 1) locus (1, 5); Run1.a is about 12.7 cM distal from the wax1 (waxy endosperm 1) locus (1, 5); Run1.a is about 15.1 cM distal from the nud1 (naked caryopsis 1) locus (8).


Plants have a dominant gene, which controls a resistant reaction to "non-Trebi-attacking" cultures of Ustilago nuda and to cultures capable of infecting the "Jet" type of resistance (7).
No images

Origin of mutant:

Natural occurrence in Trebi (PI 537442) (2, 4).

Mutational events:

Run1.a in Trebi (PI 537442, GSHO 1324) (4, 5, 7).

Mutant used for description and seed stocks:

Run1.a in Trebi (GSHO 1324).


1. Andrews, J.E. 1956. Inheritance of reaction to loose smut, Ustilago nuda, and to stem rust, Puccinia graminis tritici, in barley. Can. J. Agric. Sci. 36:356-370.
2. Livingston, J.E. 1942. The inheritance of resistance to Ustilago nuda. Phytopathology 32:451-466.
3. Robertson, D.W., G.A. Wiebe, and R.G. Shands. 1947. A summary of linkage studies in barley: Supplement I, 1940-1946. J. Am. Soc. Agron. 39:464-473.
4. Schaller, C.W. 1949. Inheritance of resistance to loose smut, Ustilago nuda, in barley. Phytopathology 39:959-979.
5. Shands, R.G. 1964. Inheritance and linkage to stem rust and loose smut resistance and starch type in barley. Phytopathology 54:308-316.
6. Skoropad, W.P., and P.V. Johnson. 1952. Inheritance of resistance to Ustilago nuda in barley. Can. J. Bot. 30:525-536.
7. Thomas, P.L. 1974. The occurrence of loose smut of barley on commercially grown cultivars possessing genes for resistance from Jet. Can. J. Plant Sci. 54:453-456.
8. Wells, S.A. 1958. Inheritance of reaction to Ustilago hordei (Pers. Lagerh.) in cultivated barley. Can. J. Plant Sci. 38:45-60.


D.R. Metcalfe and P.L. Thomas. 1976. Barley Genet. Newsl. 6:118.


J.D. Franckowiak. 1997. Barley Genet. Newsl. 26:67.