Biotype E Greenbug Resistance in Wheat Streak Mosaic Virus‐Resistant Wheat Germplasm Lines¹

Abstract

A new source of biotype E greenbug [ Schizaphis graminum (Rondani) l resistance was identified in greenhouse screening tests from a group (CI 17881–17886) of wheat ( Triticum aestivum L.) germplasm lines previously released as resistant to wheat streak mosaic virus (WSMV). The germplasm release statement from the South Dakota Agric. Exp. Stn. identified the pedigree of these lines as CI 15092/ T. speltoides //‘Fletcher’ (CI 13985) /3/ 5*‘Centurk’ (CI 15075). Our objective was to determine the parental source of the greenbug resistance and to quantify the components of resistance. The particular T. speltoides accession used in the cross was unknown; however, it appeared to be the donor of the greenbug resistance, because the other parents of the cross were susceptible to biotype E in greenhouse tests. CI 17882 and CI 17885 exhibited the highest levels of resistance. The resistance in these lines is a new source that can be exploited in the development of greenbug‐resistant wheat germplasm. New sources of greenbug resistance are needed because of the periodic occurrence of new biotypes.