Assessment of Losses Due to Onion Yellow Dwarf Virus in Onion Seed Crop

To assess losses due to onion yellow dwarf virus disease, a field experiment was conducted during 2000–2001 and 2001–2002. Seed crop was raised by using healthy and diseased bulbs separately with a susceptible variety, “Hisar-2”. Most severe infection of onion yellow dwarf virus increased number of leaves/plant to 46.4% and number of seed stalks/plant to 45.6% in comparison to control (healthy plants). All other components, viz., length of leaves, height of seed stalks, number of flowers/umbel, number of seeds/plant, 1000 seed weight and per cent seed germination were hampered to the tune of 43.0, 55.9, 39.4, 7.1, 28.5, 33.7 and 31.9% respectively, in comparison to healthy plants. Small size leaves and shorter bolters bring about common dwarf ness in plants.