The effects of two pathotypes of pea seed-borne mosaic virus on the morphology and yield of pea

Abstract

The effect of the South Australian pathotype 4 isolate (S6) of pea seed-borne mosaic virus (PSbMV-S6) on the yield components of pea (cv. Dundale) was compared in a glasshouse trial with that of a North American pathotype 1 isolate (PSbMV-US). Plants inoculated mechanically with PSbMV-S6 showed systemic vein clearing, vein banding, severe mosaic, leaf distortion, abnormal tendril curling, stunting and colour break of petals, premature axillary shoot formation, delayed flowering and pod formation, and plants matured 14 days late. Seed yield was reduced by 82% and the virus was transmitted to 31% of seedlings. In comparison, PSbMV-US induced a transient, mild leaf rolling, stunting and colour break in petals with a less noticeable effect on axillary shoot production, and plants matured 7 days late. Seed yield was reduced by 35% and the virus was transmitted to 8% of seedlings. Infected plants raised from seed of plants infected with S6 were symptomless and matured 7 days late; seed yield was reduced by 52% and 12% of their seed contained virus. In contrast, some infected plants raised from seed of plants infected with PSbMV-US showed mild leaf rolling, but there was no significant effect on yield and 7% of seed contained virus. Thus, PSbMV-S6 not only severely affects seed yield, but changes in plant habit and time of maturation may have additional deleterious effects on plant performance in field crops.