Papaya Paw paw Papaw Family Caricaceae Genus Carica

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. – Hort. Science 31: 785 -788. Tropical Horticulture - Texas A&M University

- Tall - Herbaceous - Short-lived - Large leaves - Flower in leaf axils - Seed propagated Tropical Horticulture - Texas A&M University

- Up to 10 lb. - Seed in cavity - Yellow, orange, pink, or red flesh - High vitamin A & C, and potassium Tropical Horticulture - Texas A&M University

Proteolytic enzyme extracted from latex - Meat tenderizer - Cosmetics - Leather industry - Medicinal uses Tropical Horticulture - Texas A&M University

Carica • 20 species • papaya – Lowland cultivated spp – Not found outside cultivation – Perhaps hybrid form – Only polygamous spp – Most important commercially Tropical Horticulture - Texas A&M University

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) Tropical Horticulture - Texas A&M University

Other cultivated Carica • Hybrid types - Babaco – Most commercially advanced – Seedless - parthenocarpic – Large fruit – Fresh or stewed – Vegetatively propagated Tropical Horticulture - Texas A&M University

Origin of Papaya Domesticated somewhere between southern Mexico and Guatemala Cultivated papaya Taken into Asia tropics in the 1600 s Carica spp Tropical Horticulture - Texas A&M University In Pacific Islands by 1800

Origin of Carica papaya • Tropical America – Southern Mexico – West Indies • Other spp: Mexico - Argentina • Spread via seed – 1600 s in Asian tropics – By 1800 common in Pacific Tropical Horticulture - Texas A&M University

Papaya Production in the World Three-fold increase since 1965 FAOSTAT database, 1965 - 2000 Tropical Horticulture - Texas A&M University

3 fold increase Two-fold+ increase Five-fold increase Three-fold increase Tropical Horticulture - Texas A&M University

Papaya per Capita Production in the World FAOSTAT database, 1965 -2000 Tropical Horticulture - Texas A&M University

World Production of Papaya FAOSTAT database, 2000 -2002 Tropical Horticulture - Texas A&M University

World Production of Papaya FAOSTAT database, 2000 -2002 Tropical Horticulture - Texas A&M University

World Yields of Papaya FAOSTAT database, 2000 -2002 Tropical Horticulture - Texas A&M University

• Most in Hawaii USA Production ì Produce 23, 000 MT ì Most exported to mainland USA, Canada, and Japan ì Production decrease since 1989 due to Papaya ringspot Tropical Horticulture - Texas A&M University

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 Tropical Horticulture - Texas A&M University

Type I or Pistillate Flower or female flower Tropical Horticulture - Texas A&M University

Female Papaya Flower Tropical Horticulture - Texas A&M University

Type II or Pentandria Flower Tropical Horticulture - Texas A&M University

Type III or Intermediate Flower Tropical Horticulture - Texas A&M University

Type IV or Hermaphroditic Flower or bisexual or perfect flower Tropical Horticulture - Texas A&M University

Hermaphroditic Papaya Flower Tropical Horticulture - Texas A&M University

Type V or Staminate Flower or male flower Tropical Horticulture - Texas A&M University

Male Papaya Flower Tropical Horticulture - Texas A&M University

Importance of Sex • Female – Fruit is an enlarged ovary • Male – Need pollen for pollination • Flower type influences – Thickness of flesh – Fruit shape Tropical Horticulture - Texas A&M University

Inheritance of Sex • One locus, three alleles – M 1 male – M 2 hermaphrodite or bisexual – m female • Homozygous dominant lethal – M 1 M 1, M 1 M 2 and M 2 M 2 lethal – M 1 m = male M 2 m = bisexual – mm = female Tropical Horticulture - Texas A&M University

Seedlings segregate for sex l Need to maximize the number of productive plants ÔHermaphroditic varieties maximize hermaphrodites ÔDioecious type maximize females • Plant multiple seedlings per space and rogue wrong sex Tropical Horticulture - Texas A&M University

- 2/3 hermaphroditic and 1/3 female Tropical Horticulture - Texas A&M University

Maximize Bearing Plants Hermphroditic variety • Want hermaphroditic plants • Rogue out females Ô 1 per space = 67% Ô 2 per space = 89% Ô 3 per space = 96% Tropical Horticulture - Texas A&M University

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 Tropical Horticulture - Texas A&M University

- 1/2 female and 1/2 male Tropical Horticulture - Texas A&M University

Maximize Bearing Plants Dioecious variety • Maximize females • Rogue out males Ô 1 per space = 50% Ô 2 per space = 75% Ô 3 per space = 87. 5% Ô 4 per space = 93. 7% Tropical Horticulture - Texas A&M University

Sex Can Change! • Too cool, wet, and high N Ô Female Ô Stamens become carpel like • Too hot, dry, and low N Ô Male Ô Ovaries fail to develop Tropical Horticulture - Texas A&M University

Climatic Restrictions • Optimal temperature 22 - 26 C 4 4 4 Sex expression shifts Flavor poor if cool Die if less than -1 C Die if greater than 44 C Long growing season • Susceptible to wind damage Tropical Horticulture - Texas A&M University

Cultural Restrictions • Need direct sunlight – Poor flavor if shaded • Well drained soils – Sensitive to waterlogging – Susceptible to Phytophthora • Sensitive to saline conditions Tropical Horticulture - Texas A&M University

Diseases of Papaya • Papaya ringspot virus èMost important èLimiting factor in many areas of world • • Mildew Anthracnose Root rot, Phytophthora (replant sites) Nematodes Tropical Horticulture - Texas A&M University

Papaya Ringspot Virus • Vectored by aphids – Leaf mottling and distortion – Reduce growth, yield • So severe in Florida that plants are grown as annuals Tropical Horticulture - Texas A&M University

Papaya Ringspot Virus Tropical Horticulture - Texas A&M University

Papaya Ringspot Virus Control via resistant varieties • UH Sunup and UH Rainbow – GMOs (Genetically Modified Organism) Tropical Horticulture - Texas A&M University

Insect Pests • • • Fruit flies Webworms White flies Thrips Mites Fruit spotting bugs Tropical Horticulture - Texas A&M University

Fruit flies Lay eggs in fruit Larva feed in fruit Cause rot Heat treat to kill in fruit Tropical Horticulture - Texas A&M University

Papaya Varieties Two Major Types • Hawaiian - Solo types õHermaphroditic õSmaller fruit, about 1 lb • Mexican or “fruta bomba” õDioecious õLarger fruit, up to 10 lbs Tropical Horticulture - Texas A&M University

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 Tropical Horticulture - Texas A&M University

Mexican Varieties • Locally available in many tropical regions • Much larger fruit • Flavor generally less intense • Frequently dioecious • Not as good for shipping Tropical Horticulture - Texas A&M University

Establishment • Propagated by seed v. Clean off gelatinous coat v. Dry and plant immediately v. Warm (80 F), sterile soil v. Germinate in 2 weeks v. In 10 weeks ready to transplant Tropical Horticulture - Texas A&M University

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 Tropical Horticulture - Texas A&M University

Planting • Spacing èSingle row, 8’ x 10’ Õ (435 plants per acre) èDouble row, 6’ x 12’ Õ(850 plants per acre) • Multiple seedlings per space to maximize bearing plants – 3 to 5 plants per hole until flowering Tropical Horticulture - Texas A&M University

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 Tropical Horticulture - Texas A&M University

Production Practices • No pruning • High nitrogen to encourage growth • May thin fruit to one per cluster to avoid crowding Tropical Horticulture - Texas A&M University

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 Tropical Horticulture - Texas A&M University

World Yields of Papaya FAOSTAT database, 2000 -2002 Tropical Horticulture - Texas A&M University

Post Harvest • Storage – 1 -3 weeks @ 7 -10 C • Fruit fly infestation treatment – Hot water: 20 minutes @ 120 F – Hot air: heat fruit flesh to 117 F Tropical Horticulture - Texas A&M University

International Markets • Major exporting countries – Mexico to USA and Canada – Brazil to Europe – India to Middle East – Many others Tropical Horticulture - Texas A&M University

Any Questions about Papaya? Tropical Horticulture - Texas A&M University