Indian Institute of Horticultural Research, Bangalore-560089, 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.
French bean, Phaseolus vulgaris L. is one of the most important nutritive legume vegetables grown for its tender green pods either for fresh consumption or for processing. Successful cultivation of this crop is limited by various biotic and abiotic stresses. Among the biotic stresses Mungbean yellow mosaic virus (MYMV) is the most destructive of bean diseases and has become epidemic wherever french bean is cultivated. The disease will be more severe between 27–30°C. Symptoms initially appear as yellow specs or spots on young leave with next emerging trifoliate leaf exhibiting irregular yellow and green patches and slight puckering and reduced leaf size extending to bright-yellow interveinal chlorosis. Leaves emerging after symptoms curl down, fail to expand and become stiff and leathery. Various studies indicated that the yield reduction is between 30 and 100 percent depending on the population of white flies. Therefore, there is an urgent need to develop french bean varieties resistant to MYMV. With this objective, 127 lines including 71 germplasm, 51 breeding lines and five cultivated varieties were evaluated for resistance to MYMV under field conditions during summer 2004 and 2005. It was found that seventeen lines showed tolerance with percent disease incidence ranging between 1.5 and 12.5% whereas, two lines namely IC- 525260 and IC-525284 were resistant to MYMV with less than 1.5% PDI. Susceptible line IC- 525258 showed 100% disease incidence. The performance of these resistant lines is discussed in relation to various quantitative characters.
