Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 3, 2003
Publication Date: July 1, 2004
Citation: Porter, D.R., Mornhinweg, D.W. 2004. New sources of resistance to greenbug in barley. Crop Science. 44:1245-1247. Interpretive Summary: The greenbug is a very damaging pest of barley. There are several subpopulations of greenbug (called biotypes) that have different abilities to attack and damage barley plants that carry greenbug resistance genes. One such subpopulation (biotype G) has been reported to have difficulty feeding on barley. We conducted this study to determine if barley was a host for biotype G and if biotype G was in fact a pest of barley. We tested eight barley cultivars and germplasm lines with greenbug biotype G. Seedling plants were infested with a large population of biotype G greenbugs and then the plants' reaction was rated after 21 days of feeding. We found that barley is indeed a host for greenbug biotype G, and that G is definitely a pest of barley. Biotype G killed three barley cultivars, while five were resistant to feeding damage. Three of the five resistant barleys are now considered new sources of resistance to greenbug. These new sources should prove useful in developing new greenbug resistant barley cultivars.
Technical Abstract: Most biotypes of the greenbug [Schizaphis graminum (Rondani)] are extremely damaging to barley (Hordeum vulgare L). However, greenbug biotype G has been reported to be unable to successfully feed on barley, and is described as the first greenbug avirulent to 'Wintermalt' barley (which is susceptible to all other greenbug biotypes). The objective of this study was to determine the pest status of greenbug biotype G in barley by characterizing the response of select barley cultivars and germplasm to greenbug biotype G feeding. Eight barley and four wheat cultivars and germplasm were challenged with biotype G and damage ratings recorded after 22 d of infestation. Barley is indeed a host of biotype G and genetic diversity exists within barley for reaction to attack by greenbug biotype G. Three barley cultivars were killed by biotype G, while five were resistant to feeding damage. These new sources of resistance to greenbug biotype G in barley should prove useful in the development of new greenbug resistant barley cultivars.