Impact of Pea necrotic yellow dwarf virus (PNYDV) on nodulation, N₂ fixation and yield in faba bean (Vicia faba, L.)

Pea necrotic yellow dwarf virus (PNYDV) is a novel nanovirus in Europe, affecting various grain legumes. The impact of PNYDV on nodulation, symbiotic N2 fixation and yield parameters in faba bean (Vicia faba L.) was investigated at controlled conditions in the greenhouse (2017), on-farm in natural infection foci (2018, 2019) and in a small-scale field experiment (2020). In the latter, the standard variety ‘Fuego’ was compared with the variety ‘GL Sunrise’ in early and late infections. In addition, the analogous effects for Pea enation mosaic virus (PEMV) were investigated under greenhouse conditions and the naturally occurring virus spectrum was recorded on-farm and in the field experiment. Results showed a much more severe impact of PNYDV than PEMV on nodulation, leghemoglobin status, N2 fixation and finally yield, especially in early infections. Although ‘GL Sunrise’ was rated for a less symptomatic field performance toward PNYDV than ‘Fuego’, it showed a similar susceptibility in our field experiment where PNYDV was artificially inoculated to individual plants. Further research on the effect of plant varieties on susceptibility toward PNYDV infection and its spread in single or co-infection mainly with PEMV as a function of climate change acting upon their common aphid vector is required.