|
|
Faba bean necrotic yellows virus (FBNYV, genus Nanovirus,
family Nanoviridae), causes an economically important
virus disease affecting several legume crops in many countries
of West Asia and North Africa, especially in Egypt, where
in the 1991/1992 and 1998/99 growing seasons, the virus occurred
at an epidemic scale on faba beans in Middle Egypt, leading
to significant losses. Symptoms induced by FBNYV on the cool-season
legume crops (chickpea, faba bean, lentil and pea) are mostly
stunting, leaf rolling and yellowing later leading to necrosis
and early death of the plants. Epidemic spread of this virus
was always associated with high aphid vector populations and
activity.
This virus has isometric particles (18 nm in diameter) made
up of a single capsid protein (CP) of about 22 kDa. The FBNYV
genome consists of several circular single-stranded (ss) DNA
components, each of which is about 1 kb encapsidated in a
separate particle.
FBNYV genetic resistance was found in lentil but not in faba
bean or chickpea and screening for resistance in the latter
two crops is in progress. Cultural practices such as adjustment
of planting date, roguing of infected plants early in the
season and minimal insecticide sprays reduced virus spread
significantly in faba bean fields.
Khaled Makkouk and Safaa Kumari, International Center for
Agriculture Research in the Dry Areas (ICARDA), P.O. Box 5466,
Aleppo, Syria. Email: k.makkouk@cgiar.org; s.kumari@cgiar.org
|
|
|
