Copyright © 2017 IJAIR, All right reserved 834 International Journal of Agriculture Innovations and Research Volume 5, Issue 5, ISSN (Online) 2319-1473 Screening of Grapevine Germplasm to Identify Sources of Resistance to Bacterial Leaf Spot Causing Xanthomonas campestris pv. viticola Amit K. Kamble 1, 2 , Sanjay D. Sawant 1 , Sujoy Saha 1* , Indu S. Sawant 1 1 ICAR- National Research Centre for Grapes, Pune- 412307. 2 Agrochemicals and Pest Management Department of Shivaji University, Kolhapur-416 004. Abstract – Different degrees of susceptibility were examined among the thirty eight germplasms of V. vinifera, V. labrusca and other multispecies hybrid of Vitis against Xanthomonas campestris pv. viticola under greenhouse conditions. Thompson Seedless and its mutant varieties which belong to V. vinifera were highly susceptible. Among tested germplasms of V. labrusca only Bangalore purple showed high susceptibility to Xanthomonas campestris pv. viticola. Other germplasms of V. labrusca and other multispecies hybrids showed eitherlow degree of susceptibility or resistant to bacterial leaf spot pathogen. Among the V. vinifera germplasms, white-seedless germplasms were susceptible to highly susceptible and coloured-seeded germplasms were found resistant. This study was performed to investigate putative varietal resistance against Xcv, to devise support for disease management. Keyword – Susceptibility, Vitis Vinifera, Vitis Labrusca, Xanthomonas Campestris pv Viticola. I. INTRODUCTION Grape (Vitis vinifera L.) is an important fruit cropcultivated in temperate, sub-tropical and tropical regions of the world [9]. It is affected by bacterial leaf spot, caused by Xanthomonas campestris pv. viticola (Nayudu) Dye (Xcv). Bacterial leaf spot disease has emerged as an important disease in Maharashtra, Karnataka and Andhra Pradesh during rainy season and causing around 60-80% losses in severely infected vineyards [7]. The typical symptoms of bacterial leaf spotare water soaked angular spots on the leaves which in later stage become necrotic, dark brown to black in colour [4]. Due to the rising concerns of growers, consumers and traders regarding fungicide residues at harvest which affect food safety, and the concerns of farmers regarding high cost of plant protection as well as development of resistance in Xcv against copper and streptomycin [8] the current search of the grape industry is for a resistant variety which can be used in sustainable viticulture. The most popular cultivar in India is Thompson Seedless and it was found highly susceptible to Xcv [1, 6]. Vitis vinifera was highly susceptible and other Vitis species like V. labrusca, V. rupestris, V. berlandieri, V. riparia, V. parviflora, V. champini, etc. were resistant to highly resistant [6]. Interspecies hybrids using a resistant parent had low level of disease severity, assuming that the genes for this trait were transferred to the hybrid [10]. Among the V. vinifera cultivars, the seedless cultivars were more susceptible than the seeded cultivars and among the seedless cultivars the coloured cultivars were more susceptible than the white cultivars [6]. Susceptibility may be linked to the traits of seedlessness and colour [6]. However, since 1997 a number of cultivars and germplasm has been introduced at this Centre. Among them Red Globe, Italia, Benitaka and Rubi, all belongings to the species of V. vinifera, were reported to be highly susceptible [10]. But the reaction of many of these germplasm to Xcv is not known. This study was undertaken to identify grape cultivars with commercial potential which can be directly used to replace some of the highly susceptible cultivars in areas where high infections of Xcv are reported; and also to identify sources of resistance which can be used in breeding programmes. II. MATERIALS AND METHODS A. Germplasm Thirty eight germplasm belong to Vitis vinifera (26), Vitis labrusca (7) and (5) multi-species hybrids of Vitis spp. were screened against Xcv (Table 1). Plants were raised in plastic pots filled with soil: sand: FYM mixture in 2:1:1 proportion and planted with three node cuttings. On each plant two shoots were developed and maintained with regular cultural operations. Plants were kept free from diseases, insect pests and nutrient deficiencies. Studies were conducted after 3-4 months when the plants had reached a height of 50 cm and there were 6-7 fully expanded leaves on each shoot. B. Inoculum Preparation A virulent strain of Xcv coded NRCG-XCV-A1, originally isolated from cv. Manik Chaman from Solapur region was used for study. For inoculum preparation 10 ml of sterile distilled water (SDW) was poured over a 24 h old culture plate and bacterial growth was gently scrubbed with the help of sterile nichron wire loop and collected in a sterile tube. The bacterial suspension was adjusted to a density of 10 8 cfu/ml with the help of SDW by using McFarland’s standards. C. Inoculation Method Inoculation was carried out by using leaf injection infiltration method [5]. The bacterial inoculum was injected into the mesophyll tissue of leaves in order to obtained infiltrated area of approximately one cm 2 . After inoculations, the inoculated plants were kept in FRP (Fiber Manuscript Processing Details (dd/mm/yyyy) : Received: 24/03/2017 | Accepted on : 01/04/2017 | Published : 07/04/2017