Virus infection and reproductive losses in faba bean (Vicia faba L.)

The viruses, bean yellow mosaic (BYMV), Echtes Ackerbohnenmosaik (EAMV) and bean (pea) leaf roll (BLRV) reduced seed yield in faba bean particularly when plants were infected at the pre‐and mid‐bloom stage. EAMV and BYMV, but not BLRV, delayed senescence and increased branching on glasshouse‐grown plants so that more inflorescences were produced on diseased plants; most of the additional flower buds necrosed. All three viruses increased the proportion of flower buds that became necrotic thus reducing the number of mature flowers available for pollination. This, together with enhanced abscission of recently set flowers, diminished pod production. Flower set per se was unaffected by infection. The number of ovule sites per pod and weight of individual mature seeds were also unaffected by these diseases but productivity per pod declined because of increased ovule abortions. Patterns of pod production on the inflorescence and location of mature seeds within the pod were unaffected by virus infection.