Physiological and Biochemical Characterization of Intergeneric Hybrids of Papaya

Abstract

Successful intergeneric crosses have been achieved between Carica papaya and Vasconcellea cauliflora and break the intergeneric hybridization barrier by using various nutrients. Among the nutrients used, sucrose 5 per cent, sucrose 5 per cent + boron 0.5 per cent and sucrose 5 per cent + CaCl2 0.5 per cent improved the fruit set and seed set percentage. A total number of 1197 flowers were pollinated resulted in 308 fruits. On extraction, 721 seeds were obtained from CO 7, Pusa Nanha and CP 50. Out of twenty nine F1 hybrid plants of CO 7 x Vasconcellea cauliflora, only six plants namely CO 7V1 to CO 7V6 were found free from PRSV symptoms. Similarly, out of fifty five F1 hybrid plants of Pusa Nanha x Vasconcellea cauliflora only twenty three plants namely PNV1 to PNV23 were found free from the symptoms and seventy plants namely CPV1 to CPV70 out of 335 plants of CP50 x Vasconcellea cauliflora were found free from PRSV symptoms. Physiological and biochemical characters were found to be higher in the male parent Vasconcellea cauliflora and also the cross combination involving Pusa Nanha x Vasconcellea cauliflora recorded the highest chlorophyll content and the enzymes like peroxidase and polyphenol oxidase also played a major role in plant productivity and resistance to PRSV at the time of harvest.