Serological Screening of Cowpea Genotypes for Resistance against Cowpea Aphid Borne Mosaic Virus Using DAS-ELISA

Abstract

Cowpea (Vigna unguiculata (L.) Walp), an important protein rich arid legume crop is susceptible to number of fungal, bacterial and viral diseases that severely limit the productivity. A set of 92 diverse cowpea genotypes including varieties, mutants, advanced breeding lines, exotic and indigenous collections were serologically screened for resistance against Cowpea Aphid Borne Mosaic (CABM) virus using DAS-ELISA. The genotypes grown in triplicate in a randomized block design at Trombay were mechanically inoculated with CABM virus and the resistance or susceptible reactions of each of the genotypes were recorded visually as well as serologically. Based on the extent of symptoms and serological reactions, the cowpea genotypes were classified as: highly resistant, plants without symptoms and negative for serology; resistant, plants with mild mosaic (<25%) and positive for serology; susceptible, plants with mosaic (26-75%) and positive for serology and highly susceptible, plants with severe mosaic (>75%) and other systemic symptoms and positive for serology. The study resulted in the identification of 13 highly resistant, 24 resistant, 50 susceptible and 5 highly susceptible genotypes. The chlorophyll index of susceptible genotypes as measured by SPAD chlorophyll meter was almost half that of resistant genotypes. The highly resistant genotypes against CABM virus identified in the present study after due confirmation would be incorporated in the breeding programme to develop resistance in elite genetic backgrounds.

Phenotypic and serological evaluation of cowpea (Vigna unguiculata L.Walp) genotypes for resistance to viral infection under field conditions

“…The differences in the levels of prevalence of CMV, CPSMV and CMV in the cowpea genotypes could be explained on the basis of antagonism, inoculum level, the age of the plant, climatic conditions and cultivar type (Orawu et al, 2015). The varying reactions of the cowpea genotypes to different cowpea viruses observed in the present study is quite valuable because it will enable breeders to breed for resistance against viruses that prevail at a particular location, as reported by Dhanasekar and Reddy (2015). The presence of viruses in a combination may result in synergism or antagonism effects within the infected plants.…”

“…Viruses are a major biotic constraint to cowpea production, reported to bring about yield losses ranging from 10 to 100% (Dhanasekar and Reddy, 2015). Over 140 viruses worldwide have been reported to attack cowpea and at least 11 of these occur in Africa (Hughes and Odu, 2003).…”

“…Development of resistant varieties against different type and strain of viruses entails screening of germplasm in a particular agro-climate for identification of resistance to the particular strain prevailing in that region. However, field screening for virus resistance based solely on symptoms is not reliable (Shoyinka et al, 1997), as different viruses display overlapping symptoms (Dhanasekar and Reddy, 2015). Moreover, plants can also exhibit virus-like symptoms when exposed to adverse weather conditions, soil nutrient imbalances, pest infestations and non-viral infections (Hughes and Odu, 2003).…”

Additive interactions of unrelated viruses in mixed infections of cowpea (Vigna unguiculata L. Walp)

“…IITA reported that one of its 2003 milestones was the initiation of field testing of transgenic cowpea plants. Cowpea lines resistant to CABMV have been identified (Dhanasekar and Reddy, 2015 ).…”

The Challenge of Protein Crops as a Sustainable Source of Food and Feed for the Future

“…IITA reported that one of its 2003 milestones was the initiation of field testing of transgenic cowpea plants. Cowpea lines resistant to CABMV have been identified (Dhanasekar and Reddy, 2015).…”