Department of Plant Pathology, CCS Haryana Agricultural University, Hisar-125 004, India.
Abstracts of the papers presented at the XVIII National Conference of Indian Virological Society at Post Graduate Institute of Medical Education and Research, Chandigarh, India, December 11–13, 2008.
Onion is an important vegetable and spice crop with a productivity of 11.99 tones/ha. in India. Production of bulb and seed crop of onion is affected by various diseases and pests out of which onion yellow dwarf virus (OYDV) is the most important and widespread. OYDV belonging to Potyviridae family was reported from West Virginia, USA as early as 1916 whereas an incidence of 25–30% was recorded for the first time from Delhi on seed crop in 1963. The prominently occurring diagnostic symptoms are severe stunting of plants and flattening of leaves which undergo crinkling and formation of yellow streaks and stripes in the onion plants. In the seed crop affected leaves and umbel stalks (scapes) show various degrees of yellowing with twisting of the umbel stalks and lopping over of the leaves. All this results into reduction in yield of seed. It was observed that symptoms varied in onion cultivar HS-2 in the field growing plants in Haryana and NCR areas. Leaf samples were taken and ELISA confirmed the presence of OYDV in the onion plants showing variations in the symptomatology. Different symptoms based variants of OYDV were also found to hamper the yield of seed and onion bulbs differently. Incidence, symptoms and yield of different symptom based variants of OYDV infecting onion in Northern India will be discussed.
