Papaya Paw paw Papaw Family Caricaceae Genus Carica Species papaya
Papaya Readings (On web page) Nishina et al., 2000. Papaya Production in Hawaii. CTAHR, F&N-3. Manshardt, 1999. ‘UH Rainbow’ Papaya. A High-Quality Hybrid with Genetically Engineered Disease Resistance. CTAHR, NPH-1 Kempler and Kabaluk. 1996. Babaco (Carica pentagona Heilb.): A possible crop for the greenhouse. HortScience 31:785-788.
Carica 20 species papaya Lowland cultivated spp Not found outside cultivation Perhaps hybrid form Only polygamous spp Most important commercially Other Cultivated Carica Highland species Common in upland Valleys of Ecuador and Colombia Taste different, less sweet Soups, stews, sweets, fresh Genes for breeding (cold/disease resistance) Other cultivated Carica Hybrid types – Babaco Most commercially advanced Seedless – parthenocarpic Large fruit Fresh or stewed Vegetatively propagated Origin of Papaya Origin of Carica papaya Tropical America Southern Mexico West Indies Other spp: Mexico – Argentina Spread via seed 1600s in Asian tropics By 1800 common in Pacific Papaya Production in the World
Papaya per Capita Production in the World World Production of Papaya World Production of Papaya World Yields of Papaya USA Production Most in Hawaii Produce 23,000 MT Most exported to mainland USA, Canada, and Japan Production decrease since 1989 due to Papaya ringspot
Fruiting of the Papaya
Fruit hang along trunk Flower in leaf axils Most are dioecious Some are hermaphroditic or perfect flowered Five classes of flowers Type I or Pistillate Flower Female Papaya Flower Type II or Pentandria Flower Type III or Intermediate Flower Type IV or Hermaphroditic Flower Hermaphroditic Papaya Flower Type V or Staminate Flower Male Papaya Flower Importance of Sex Female Fruit is an enlarged ovary Male Need pollen for pollination Flower type influences Thickness of flesh Fruit shape Inheritance of Sex One locus, three alleles M1 male M2 hermaphrodite or bisexual m female Homozygous dominant lethal M1M1, M1M2 and M2M2 lethal M1m = male M2m = bisexual mm = female Seedlings segregate for sex Need to maximize the number of productive plants Hermaphroditic varieties maximize hermaphrodites Dioecious type maximize females Plant multiple seedlings per space and rogue wrong sex
Maximize Bearing Plants Hermphroditic variety Want hermaphroditic plants Rogue out females 1 per space = 67% 2 per space = 89% 3 per space = 96% Female or Dioecious Types Need one male for every 12-15 females 6-8% males Fruit is better if good pollination Pollination by wind and moths
Maximize Bearing Plants Dioecious variety Maximize females Rogue out males 1 per space = 50% 2 per space = 75% 3 per space = 87.5% 4 per space = 93.7% Sex Can Change! Too cool, wet, and high N Female Stamens become carpel like Too hot, dry, and low N Male Ovaries fail to develop Climatic Restrictions Optimal temperature 22 – 26 C Sex expression shifts Flavor poor if cool Die if less than -1C Die if greater than 44C Long growing season Susceptible to wind damage Cultural Restrictions Need direct sunlight Poor flavor if shaded Well drained soils Sensitive to waterlogging Susceptible to Phytophthora Sensitive to saline conditions Diseases of Papaya Papaya ringspot virus Most important Limiting factor in many areas of world Mildew Anthracnose Root rot, Phytophthora (replant sites) Nematodes Papaya Ringspot Virus Vectored by aphids Leaf mottling and distortion Reduce growth, yield So severe in Florida that plants are grown as annuals Papaya Ringspot Virus Papaya Ringspot Virus UH Sunup and UH Rainbow GMOs (Genetically Modified Organism)
Insect Pests Fruit flies Webworms White flies Thrips Mites Fruit spotting bugs Fruit flies Papaya Varieties Two Major Types Hawaiian – Solo types Hermaphroditic Smaller fruit, about 1 lb Mexican or “fruta bomba” Dioecious Larger fruit, up to 10 lbs Hawaiian Varieties Hermaphroditic Solo types Common in US markets Fruit small, firm, sweet Plant smaller ~ 8’ Sex expression more stable Series of inbred seed lines developed in Hawaii Most widely grown is “Sunrise” variety Mexican Varieties Locally available in many tropical regions Much larger fruit Flavor generally less intense Frequently dioecious Not as good for shipping Establishment Propagated by seed Clean off gelatinous coat Dry and plant immediately Warm (80 F), sterile soil Germinate in 2 weeks In 10 weeks ready to transplant Site Selection “Virgin soil” preferred Replant sites High levels of Phytophthera palmivora “Virgin soil” technique Fungicide drench in planting hole Fallow of 3-5 years
Planting Spacing Single row, 8’ x 10’ (435 plants per acre) Double row, 6’ x 6’ x 12’ (850 plants per acre) Multiple seedlings per space to maximize bearing plants 3 to 5 plants per hole until flowering Cropping Cycle From planting begin to fruit in 10-12 months Begins to flower in 4-8 months Fruit develops in 4-6 months Possible to grow as annual Commercially can fruit for 3-4 years Production Practices No pruning High nitrogen to encourage growth May thin fruit to one per cluster to avoid crowding Harvesting and Yields Climacteric fruit Harvest yellow green Dark green fruit will not ripen Potential yield 100 tons/ha or 40 tons/acre Average yield 15-25 tons/ha or 6-10 tons/acre World Yields of Papaya Post Harvest Storage 1-3 weeks @ 7-10C Fruit fly infestation treatment Hot water: 20 minutes @ 120F Hot air: heat fruit flesh to 117F International Markets Major exporting countries Mexico to USA and Canada Brazil to Europe India to Middle East Many others Any Questions about Papaya?