Part I. R& D Status - pcaarrd - Department of Science and Technology

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et al. 1995). These aphids acquire and transmit virus very quickly through sap feeding. It is still unknown, however, whether the virus is transmissible via the seed, but it may be seedborne (Bajet 1996). Bato et al. (1993) identified nine natural enemies of aphids. These are coccinelid beetle, syphid fly, chalcids, braconids, chrysopids, staphylinids, mirids, hemerobiid, and Entomophtora sp. (a fungus). Scientists use serological assays, mechanical transmission, electron microscopy, or a mix of the three to detect PRSV-infected papaya. Using serological assays, scientists confirmed that the Philippine PRSV is identical to the viruses in Thailand, Australia, Hawaii, and Taiwan (Bajet 1996).The PRSV strain was successfully isolated in zucchini squash (Cucurbita pepo cv. Blackjack) (Bajet 1997; 1996). Along with okra, corn, mungbean, eggplant, cucumber, jelly melon, pumpkin, squash, centrosema, ‘gabi,’ ‘upo,’ ‘patola,’ ‘melon-melonan,’ and ‘balatong-aso,’ zucchini squash serves as an alternate host of the vectors and the virus (Sumalde 1995). The isolate produced the typical symptoms in both the squash and papaya. Similarly, the molecular variability of PRSV can be known through cloning and deoxyribonucleic acid (DNA) sequencing (Aquino and Valencia 2001). Based on the entire cp gene sequences, isolates from Bulacan, Cavite, Quezon, Isabela, and Marinduque were identified at 97–98% sequence homology. Scientists need to further verify isolates variability and dendogram development based on genetic coefficient to confirm the virus’ genetic variability. Planting PRSV-tolerant variety like the Sinta papaya is one of the recommended practices to manage PRS (Villegas 1996 a and b; Sumalde et al 1995; Bato et al. 1993). The Sinta papaya could only serve as a stopgap measure in the absence of resistant varieties. It must be combined with other disease management strategies such as: • Roguing or proper disposing of infected plants; • Controlling the vector by eliminating alternate hosts; • Intercropping with taller crops or by spraying insecticides; • Isolating plants; • Subjecting plants into quarantine; • Conducting proper cultural management practices such as weeding, fertilization, and irrigation during dry season; and • Treating papaya as an annual crop rather than as a perennial crop. These disease management strategies were being employed in the papaya rehabilitation and development project in Southern Tagalog and in the Bicol region (Sumalde et al. 1997; 1995). The project also involved information, education, and communication (IEC) campaigns through consultative meetings, training-seminars, and trimedia to enhance awareness of papaya growers on PRSV and to strengthen linkages among concerned stakeholders. The IEC materials of this project were supplemented with other publications from other researchers in the NARRDN. In Davao, Pableo et. al. of BPI-Davao National Crops Research and Development Center (BPI- DNCRDC) suggested practical steps to control spider mites. These include inspection, judicious spraying with formetana, and removal of nonfunctional leaves. Modified Atmosphere (MA) Storage and VHT of Solo Papaya Postharvest Training and Resarch Center (PHTRC) researchers’ findings on the postharvest handling of papaya focused mostly on the Solo variety. Serrano (1996) optimized the application of MA storage of the Solo papaya to delay ripening during commercial shipment trials from Misamis Oriental to Laguna. On the other hand, Lizada et al. (1991) determined the effect of VHT on the ripening characteristics, fruit injury, and disease incidence on the Solo papaya. 18 ............................................................................................................. R&D Status and Directions
Institutional Capability ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ The institutions involved in papaya researches are UPLB, Cavite State University , University of Southern Mindanao, Leyte State University (formerly Visayas State College of Agriculture), Bicol University College of Agriculture and Forestry, Don Mariano Marcos Memorial State University, BPI, and BPI-DNCRDC, and DA regional stations. These agencies implement basic (especially UPLB) and applied (particularly BPI, DA, and other agricultural universities) research projects. The lack of institutional linkages on papaya R&D and weak technology transfer are among the major concerns. Papaya.............................................................................................................................................................. 19
Page 1 and 2: R&D Status ○ ○ ○ ○ ○ ○
Page 3 and 4: Papaya Industry Situation ○ ○
Page 5 and 6: After the PRS Outbreak From a pre-P
Page 7 and 8: 30000 1997 1998 1999 2000 2001 2500
Page 9 and 10: Table 5. Volume (t) and value (‘0
Page 11 and 12: Table 6. SWOT analysis on the Phili
Page 13 and 14: Table 8. Studies on papaya by disci
Page 15: Interspecific Hybridization for PRS

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