Department of Botany, S.D.J.P.G. College, Chandeshewar, Azamgarh, Department of Botany, D.D.U. Gorakhpur University, Gorakhpur, India.
Abstracts of the papers presented at the International Conference of Indian Virological Society on “Emerging and Re-emerging viral Diseases of the Tropics and Subtropics” at Indian Agricultural Research Institute, New Delhi, India, December 11–14, 2007.
Viral diseases are major limiting factor in raising profitable healthy crops of cowpea. The most common physiological and biochemical changes brought about by viruses in plants are an increase in rate of respiration and decrease in rate of photosynthesis which affects the productivity of plants and results in lower yield of plants. Primary productivity was measured by leaf disc method on 20, 40 and 60 days after inoculation of virus, when compared with healthy plants of same age it was found that the productivity was less and respiration was high in diseased plant. To study the effect of virus infection on yield, one week, three weeks and five weeks old cowpea plants were inoculated by virus. Effect of virus infection on number of flowers and pods per plants, pod size, number of seed per pod, seed size and seed weight were studied and it was found that one week old plant was most susceptible to virus infection and infection caused maximum yield loss in one week old plant showing inverse relationship between age of infection and yield loss.
