|Mornhinweg, Dolores - Do|
Submitted to: Plant Breeding
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/10/2004
Publication Date: 11/1/2004
Citation: Porter, D.R., Mornhinweg, D.W. 2004. Characterization of greenbug resistance in barley. Plant Breeding. 123:493-494. Interpretive Summary: The greenbug is an extremely damaging pest of barley, particularly in the Southern Great Plains of the USA. Winter barley targeted for production in this region should incorporate genetic resistance to the greenbug. Right now, there are two sources (i.e., genes) of resistance to greenbug in barley and we don't know which is the better source to use in developing greenbug-resistant barley cultivars. In this study we tested both resistance genes (Rsg1a and Rsg2b) against six greenbug biotypes (a biotype is a virulent form of greenbug). We found that both genes were resistant against all six biotypes of greenbug, but Rsg1a provided a higher level of protection against five of the six biotypes tested. Based on the results of this study, we are recommending that breeders us the Rsg1a resistance gene, carried in Post 90 winter barley, when developing greenbug-resistant barley.
Technical Abstract: The greenbug [Schizaphis graminum (Rondani)] is an extremely damaging pest of barley (Hordeum vulgare L), particularly in the Southern Great Plains of the USA. Winter barley targeted for production in this region should incorporate resistance to greenbug in the form of the resistance gene Rsg1a (in 'Post 90') or Rsg2b (in PI 426756). This study was conducted to fully characterize the resistance profile of these two genes against important greenbug biotypes, and to determine which of the two resistance genes is most effective in protecting barley from the greenbug. Eight barley and four wheat cultivars and germplasms were challenged with six greenbug biotypes and damage ratings were recorded for each combination. In five of the six tests, Post 90 was significantly more resistant than PI 426756 to greenbug feeding damage. Based on the results presented here, we conclude that the resistance gene, Rsg1a, in Post 90 is the better choice for use in breeding programs and will provide better protection than Rsg2b against the greenbug.