International Database for Barley Genes and Barley Genetic Stocks

BGS 577, Reaction to Schizaphis graminum 2 (greenbug), Rsg2

BGN  37:283
Stock number: BGS 577
Locus name: Reaction to Schizaphis graminum 2 (greenbug)
Locus symbol: Rsg2

Previous nomenclature and gene symbolization:



Monofactorial dominant (1).
Location is unknown.


Resistant seedlings infested with greenbugs (aphids) are not killed or severely stunted by a buildup of the greenbug population, but susceptible seedlings are killed or severely stunted (1, 4). The resistance provided by PI 426756 (4 to 5 readings on a 1 to 9 scale) to most S. graminum biotypes was less effective than that provided the Rsg1.a gene in Post 90 (PI 549081) (2 to 3 readings) (3). PI 426756 was confirmed to provide resistance (2 to 3 readings) to the TX1 isolate of S. graminum, which produces a susceptible reaction (9 reading) on Post 90 (2).
No images

Origin of mutant:

Natural occurrence in Joa (PI 426756) (1, 4).

Mutational events:

Rsg2.b in PI 426756 (1).

Mutant used for description and seed stocks:

Rsg2.b in PI 426756 (GSHO 2513).


1. Merkle, O.G., J.A. Webster, and G.H. Mogen. 1987. Inheritance of a second source of greenbug resistance in barley. Crop Sci. 27:241-243.

2. Porter, D.R., J.D. Burd, and D.W. Mornhinweg. 2007. Differentiating greenbug resistance genes in barley. Euphytica 153:11-14.

3. Porter, D.R., and D.W. Mornhinweg. 2004. Characterization of greenbug resistance in barley. Plant Breed. 123:493-494.

4. Webster, J.A., and K.J. Starks. 1984. Sources of resistance in barley to two biotypes of greenbug Schizaphis graminum (Rondani), Homoptera: Aphididae. Protect. Ecol. 6:51-55.


J.D. Franckowiak. 1997. Barley Genet. Newsl. 26:503.


J.D. Franckowiak. 2007. Barley Genet. Newsl. 37:283.