Resistance to seed transmission of cucumber mosaic virus in narrow-leafed lupins (Lupinus angustifolius)

摘要

Cucumber mosaic virus (CMV) is seed-transmitted in L. angusti,folius (narrow-leafed lupin) and plants that grow from infected seed are the primary source of inoculum for field epidemics. Resistance to seed transmission of CMV was sought in cultivars, breeding lines and wild types of this species. The field screening method developed was based on spreader rows, where a susceptible cultivar (Wandoo) with high intrinsic seed infection levels was grown on either side of every test row, and CMV spread occurred by natural aphid transmission. Inoculum pressure was so great that spreader and test rows became virtually 100% infected. Harvested seed from each test row was assessed for the level of infection present by testing for the presence of CMV in the radicles of newly germinated seeds or in leaves of seedlings by ELISA. This method was used successfully from 1987 to 1992 to screen lines for relative resistance/susceptibility to CMV seed transmission. Based on their intrinsic CMV seed transmission rates during the experiments test lines were categorized into four groups: moderately resistant (1-6% seed transmission, as in cvv. Danja and Frost), moderately susceptible (6-20% seed transmission, as in cvv. Illyarrie, Yorrel and Gungurru), susceptible (20-35% seed transmission, as in cv. Wandoo), and very susceptible (35-75% seed transmission, as found in some breeding lines and wild types). No lines were highly resistant (20%) should be culled out.