A comparitive study of changes in quality attributes of fruit pulp due to Papaya Ring Spot Virus-P infection in Carica papaya and its wild relatives

Abstract

Production of papaya is hampered by a deadly disease known as Papaya Ring Spot Virus. When infected in the early stages of growth, fruit production is severely affected and upon the later stages of infection, fruits of lower quality were produced. Maintaining the balance between fruit quality and disease resistance will be toilsome for breeders during screening of the germplasm or hybrid progenies. This study was conducted in order to identify papaya genotypes which have lower fluctuations in fruit quality in response to the viral infection. Six cultivars of Carica papayanamely Arka Surya, Arka Prabhath, Red Lady, Pusa Dwarf, Pusa Nanha and TNAU papaya CO8, two intergeneric hybrids of Arka Surya and Vasconcellea cauliflora(IGH1 and IGH2) and three wild relatives V. cauliflora, V. goudotianaand V. parviflora were evaluated in this study. Fruit quality parameters viz., total soluble solids, total sugars, reducing sugars, titrable acidity, ascorbic acid and carotene concentration were estimated in these eleven genotypes which was inoculated at nursery stage, vegetative and flowering stage. When the plants were infected at nursery stage, few accessions viz., Pusa Nanha, TNAU papaya CO8, IGH1, IGH2 and the wild species yielded fruits. TSS, total sugar and reducing sugar decreased significantly in these fruits whereas, titrable acidity was increased notably, while no changes were recorded in ascorbic acid and carotene content. Similar observations were recorded when the accessions were subjected to infectionat vegetative stage. However, the TSS and sugar content of the fruits were found to marginally increase as compared to control when the genotypes were infected at flowering stage. Among the accessions, minimum changes in fruit quality parameters were observed in wild species followed by papaya variety Pusa Nanha.