Screening of F1 intergeneric hybrid progenies of papaya for papaya ringspot virus (PRSV) resistance

The present investigation was undertaken to develop papaya ringspot virus (PRSV) resistant papaya hybrids through intergeneric hybridization. Intergeneric hybridization was done involving nine Carica papaya cultivars as female and Vasconcellea cauliflora as male. Intergeneric F1 hybrids were artificially inoculated. Artificial screening for papaya ringspot virus was carried out 27 days after sap inoculation. Out of twenty nine F1 hybrid plants of CO 7 x V.cauliflora, only six plants (CO 7V1 to CO 7V6) were found free from PRSV symptoms. Similarly, out of fifty five F1 hybrid plants of Pusa Nanha x V. cauliflora only twenty three (PNV1 to PNV23) were found free from the symptoms and seventy plants (CPV1 to CPV70) out of 335 plants of CP50 x V. cauliflora were found free from PRSV symptoms. Molecular markers ISSR markers were used to check and verify the hybridity. The resistance of the hybrids and parents were subjected to DAS ELISA test. ELISA titre value varied from 0.216 to 0.927. Among the parents, the resistant male parent V. cauliflora had recorded the lowest titre value of 0.216. However, the susceptible female parent CO 7 recorded the highest titre value of 0.972 followed by Pusa Nanha 0.952 and CP50 0.942. Among the hybrids ELISA titre value ranged from 0.218 to 0.29.