Pigeonpea is a major pulse crop of the dry tropics mainly cultivated under marginal conditions by millions of resource poor farmers in the Indian subcontinent. The crop is used in many ways and plays an important role in food security. It is important in allowing the poor access to food and employment. Pigeonpea seed is the major dietary protein source for an estimated 1.1 billion people in the subcontinent. Sterility mosaic disease (SMD), endemic in the subcontinent is a major constraint on pigeonpea production and the economic well being of the poor farmers. Cultivation of broad-based SMD resistant varieties is most feasible and eco-friendly way to manage the disease. To achieve this, this project was undertaken to characterise the agent of SMD and its isolates and develop sensitive diagnostic tools and to select and supply broad-based SMD-resistant genotypes to the farmers and NARES.