|Mornhinweg, Dolores - Do|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2005
Publication Date: 12/2/2005
Citation: Mornhinweg, D.W., Brewer, M.J., Porter, D.R. 2006. Effect of Russian wheat aphid on yield and yield components of field grown susceptible and resistant spring barley. Crop Science 46:36-42. Interpretive Summary: RWA is a devastating pest on barley. Introduced into the US in 1986 it is now established in the western US where yield losses occur every year. This paper reports the effect of RWA feeding on RWA-resistant germplasm lines that have different levels of resistance to RWA and also on susceptible cultivars currently grown by US farmers. The effect was measured in grain yield and yield components for small grains ' tiller number, seeds per head, and seed weight. This information will not only be of interest to scientists in the area of insect plant interactions but will also help plant breeders effectively utilize these germplasm lines in their breeding programs.
Technical Abstract: Russian wheat aphid, Diruaphis noxia (Mordvilko), (RWA), an established pest in the western US, is devastating to barely production. RWA-resistant spring barley germplasm lines have been developed in an effort to control RWA without the use of environmentally and economically expensive insecticides. The major component of resistance in these lines is tolerance. How resistant germplasm lines successfully respond to RWA is not only important in understanding aphid plant interactions but is also important to best utilize these lines in a breeding program. This study was conducted to determine the effect of RWA on yield and yield components of fifteen RWA-resistant spring barley germplasm lines with differing levels of seedling RWA resistant ratings ranging from resistant to moderately resistant and moderately susceptible, and four susceptible cultivars at two field locations in Wyoming. Treated plots were artificially infested with RWA while non-treated controls were kept aphid free with pesticide application. Grain yield of all but one of the highly resistant germplasm lines either increased, or was maintained regardless of location. Grain yield of moderately resistant lines either increased, was unaffected, or decreased depending upon line and location. Grain yield reduction was severe for susceptible cultivars. RWA feeding significantly affected 100 kernel weight at both locations, while tiller number and kernels per spike were significantly affected at Laramie only. Although significant differences in yield components were observed, they varied with resistant germplasm line. No single yield component or combination of components could explain the tolerance of RWA-resistance in all germplasm lines.