The effect of alfalfa mosaic virus on productivity of annual barrel medic, Medicago truncatula

Abstract

Alfalfa mosaic virus (AMV) infection of the annual barrel medic, Medicago truncatula, has been shown to cause significant reductions in growth and productivity in field and pot trials. The degree of reduction was dependent on the medic cultivar and the virus isolate. In some experiments herbage production was reduced by more than 50%. Although infection did not appear to be associated with significant changes in root growth, root nodulation of infected plants was about one-third less than that of healthy plants. Two AMV isolates showed different effects on seed production. Infection with one virus isolate was associated with a 15-30% decrease in seed production, and the virus was detected in more than 2% of seed from the infected plants, whereas the other isolate failed to reduce seed yield and did not appear to infect any seeds.