Ashfaq et al., J. Anim. Plant Sci. 24(3):2014 791 SCREENING FOR RESISTANCE TO CUCUMBER MOSAIC CUCUMOVIRUS IN CHILLI PEPPER M. Ashfaq * , S. Iqbal, T. Mukhtar and H. Shah ** Department of Plant Pathology, Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, Pakistan. ** Crop Diseases Research Institute, National Agricultural Research Center, Park Road, Islamabad. * Corresponding Author: mashfaq1642@gmail.com ABSTRACT Cucumber mosaic cucumovirus (CMV) is destructive pathogen with widest host range, infecting more than 100 botanical families comprising more than 500 genera and 1300 plant species. Chilli pepper is a significant cash crop of Pakistan among vegetable grown. The identification of genetic resistance to CMV in Pakistan (CMV chilli isolate) in chilli pepper is of economic importance. Thus, 40 Chilli pepper genotypes, both local and imported, were evaluated by mechanical/ manual virus inoculation and resistance to CMV chilli isolate was examined by visual observations and enzyme-linked immunosorbent assay (DAS-ELISA). On the basis of 0-5 disease rating scale and ELISA, nine genotypes viz., C-2, CV- 2, CV-5, BSS-269, PGRI, M-2001, CM-2001, M-97 and CP-328 were remained free of infection and catalogued as highly resistant. Rest of the genotypes exhibited characteristic symptoms like mosaic, mottling, leaf curling and reduced leaf size depending upon tested genotypes. Among these genotypes, five were categorized as resistant, seven as moderately resistant, eight as moderately susceptible and 11 as susceptible. These resistant and moderate resistant genotypes could be used by farmers in cultivation under integrated production systems and by breeders in developing new chilli pepper hybrid resistant genotypes to CMV. Key words: Chilli pepper, Cucumber mosaic virus, resistant, ELISA. INTRODUCTION Chilli pepper (Capsicum annum L.) is one of the most important members of solanaceous vegetables grown in Pakistan and ranked at third position after potato and tomato (Iqbal et al., 2012). Chilli contains more vitamins C than any other vegetable crop (Dexiang, 1994). Among the various factors limiting to chilli production in Pakistan, viruses appear to be significant production constraints. Among these viruses, Cucumber mosaic virus (CMV) causes severe/ economic yield reduction in chillies. Doolittle (1916) and Jagger (1916) first described Cucumber mosaic virus (CMV) and the virus was assigned to the Cucumovirus group as the type member. CMV is tri-partite, single-stranded, +ive sense RNA virus. Intrinsically RNA viruses are heterogeneous and to a certain extent their heterogeneous nature is because of error-prone nature of RNA replication (Ding et al., 1995; Domingo and Holland, 1994). CMV has a very broad host range of wild and cultivated plants, with more than 1300 known hosts including some monocotyledons and a great number of dicotyledons (Chen et al., 2006). Tomlinson (1978) described CMV as the most economically important virus in cowpea, celery, cucurbits, pepper, lettuce and tomato. Other researchers (Palukaitis et al., 1992; Gafny et al., 1996, Davis et al., 1996, Latham et al., 1999) reported that Banana, Pasture legumes, Kava and ornamentals are also affected by CMV. CMV is easily transmitted by mechanical inoculation of plant sap and naturally transmitted (non- persistently) by 80 aphid species (Palukaitis and Garcia- Arenal, 2003). Use of disease resistant crop varieties is regarded as an economical and durable method for controlling plant diseases, especially those caused by viruses. Recently the role of mineral metabolism and total soluble phenols in imparting resistance/susceptibility against viral diseases of plants has also been manifested (Ashfaq et al., 2014). A good deal of research work has been directed to identify resistant sources under diverse environmental conditions and continuing screening of available genotypes and new germplasm, which constitutes the basis of this work has been suggested by several research workers ( Bashir et al., 2005; Ashfaq et al., 2007; Ashfaq et al., 2008; Ashfaq et al., 2014). Therefore, to evaluate and catalogue sources of CMV resistant genotypes, forty local and exotic chilli pepper genotypes were screened by mechanical inoculation. The level of resistance to CMV accumulation in chilli pepper leaf tissues was evaluated using a combination of visual symptom observations and enzyme-linked immunosorbent assay (ELISA). MATERIAL AND METHODS Virus source and maintenance: A Pakistani isolate of chilli pepper infecting CMV (CMV chilli isolate) was used as virus source for mechanical inoculation (Iqbal et The Journal of Animal & Plant Sciences, 24(3): 2014, Page: 791-795 ISSN: 1018-7081