Present Status of Viral Diseases of Grapevine (Vitis Vinifera L.) and their Management Strategies in India

Grapevine is an important fruit crop cultivated in temperate, subtropical and tropical conditions in India. The maximum share in area, production, and productivity of grapes is governed by four states viz. Maharashtra, Karnataka, Tamil Nadu and Andhra Pradesh. The sudden and drastic changes in climatic conditions and the emergence of diseases have made grapevine cultivation more challenging. Fungal and bacterial diseases are the major constraints in the grapevine production. Besides, some viral diseases like Grapevine Leafroll Disease (GLD) and Rupestris Stem Pitting Associated Diseases (RSPD) are reported in Indian vineyards. Although the presence of Grapevine Leafroll-Associated Viruses (GLRaVs) viz., GLRaV-1, GLRaV-3, and GLRaV-4 are known the impact on yield and quality of the grapes is not yet studied. Similarly, the Rupestris Stem Pitting Associated Virus (RSPaV) is known to infect the Indian vineyards of different locations but a complete understanding of their overall impact on vineyards is lacking. Therefore, it is presumed that fewer or no losses occur due to GLD and RSPD diseases. There is a strong need for hours to study the impact of known viruses on physiological and yield contributing parameters. In addition to this, robust, rapid and reliable diagnostic techniques are required for the detection of known and unknown viruses. The presence of new and emerging viruses in the Indian vineyards cannot be overlooked. Further, for the management of the viruses and avoiding their spread, the availability of Disease-Free Quality Planting Material (DFQPM) is a prerequisite. To produce DFQPM, various tissue culture techniques need to be standardized for the elimination of the virus/es from the diseased vines. The Tissue Culture-Raised Quality Planting Material (TCQPM) needs to be further tested for genetic purity (true-to-type) and virus indexing to confirm DFQPM. By considering the importance of DFQPM, recently, the National Horticulture Board (NHB), Govt. of India in association with the Asian Development Bank (ADB) has initiated a National Mission on Clean Plant Programme. The implementation of this initiative is more challenging and expected to open different avenues of research and development in the production of DFQPM for the growers. This is an important and timely beginning of the production of DFQPM.