Abstract

A pot culture study was conducted during 2009-2010 to screen the papaya cultivars under polyhouse conditions for resistance against ringspot caused by papaya ringspot virus – type P at Tamil Nadu Agricultural University, Coimbatore. Plants were artificially inoculated with PRSV–P strain in the polyhouse. The resistance was assessed by symptom expression, disease score, DAS-ELISA, chlorophyll and biochemical parameters. All the papaya cultivars inoculated with virus tested were ELISA positive, whereas the uninoculated control plants tested were ELISA negative. The chlorophyll pigments were lower in virus inoculated plants than those corresponding uninoculated controls. However, peroxidase, polyphenol oxidase and total phenols were higher in virus inoculated plants than uninoculated controls. The results suggested that the CP 50, a dioecious papaya was identified as tolerant cultivar against PRSV-P under Coimbatore conditions based on the assessment in the polyhouse.

Keywords: PRSV, papaya, Carica papaya, disease score, ELISA, chlorophyll, enzymes