Papaya Readings Papaya (On web page) • Nishina et al., 2000. – Papaya Production in Hawaii. Paw paw – CTAHR, F&N-3. • Manshardt, 1999. Papaw – ‘UH Rainbow’ Papaya. A High-Quality Hybrid with Genetically Engineered Disease Resistance. Family Caricaceae – CTAHR, NPH-1 Genus Carica • Kempler and Kabaluk. 1996. – Babaco (Carica pentagona Heilb.): A possible crop for the Species papaya greenhouse. – HortScience 31:785-788. Tropical Horticulture - Texas A&M University - Up to 10 lb. -Tall - Seed in cavity - Herbaceous - Yellow, - Short-lived orange, pink, - Large leaves or red flesh - Flower in leaf - High vitamin axils A & C, and potassium - Seed propagated Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Proteolytic enzyme Carica extracted from latex • 20 species • papaya – Lowland cultivated spp - Meat tenderizer – Not found outside cultivation -Cosmetics – Perhaps hybrid form - Leather industry – Only polygamous spp - Medicinal uses – Most important commercially Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Other Cultivated Carica Other cultivated Carica • Highland species – Common in upland Valleys of Ecuador • Hybrid types - Babaco and Colombia – Most commercially advanced – Taste different, less sweet – Seedless - parthenocarpic – Soups, stews, sweets, fresh – Large fruit – Genes for breeding (cold/disease – Fresh or stewed resistance) – Vegetatively propagated Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Origin of Papaya Origin of Carica papaya • Tropical America – Southern Mexico – West Indies Cultivated Domesticated papaya somewhere In Pacific • Other spp: Mexico - Argentina between Taken into Asia Islands southern Mexico tropics in the 1600s by 1800 and • Spread via seed Guatemala – 1600s in Asian tropics Carica spp – By 1800 common in Pacific Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Papaya Production in the Papaya Production in the World Americas Papaya Production in the World 3000 6000 2500 5000 Americas 2000 4000 1500 3000 1000 6000 1,000s mt Three-fold increase since 1965 1,000s mt 2000 500 1000 0 5000 1965 1970 1975 1980 1985 1990 1995 2000 0 1965 1970 1975 1980 1985 1990 1995 2000 Five-fold increase 4000 3 fold increase 3000 Papaya Production in Africa Papaya Production in Asia 1,000s mt 2000 1500 2000 1000 Africa Asia 1000 1500 1000 500 0 mt 1,000s 1,000s mt 1965 1970 1975 1980 1985 1990 1995 2000 500 0 0 1965 1970 1975 1980 1985 1990 1995 2000 1965 1970 1975 1980 1985 1990 1995 2000 Two-fold+ increase FAOSTAT database, 1965 - 2000 Three-fold increase Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University World Production of Papaya Papaya per Capita Production in the World FAOSTAT database, 1965-2000 Region 1,000 mt % 1 0.9 Africa 1,228 21% 0.8 0.7 Asia 1,727 29% 0.6 0.5 Americas 2,923 50% 0.4 (kg/person) 0.3 USA 23 < 0.5 % Per Capita Production Production Capita Per 0.2 0.1 0 Total 5,901 1965 1970 1975 1980 1985 1990 1995 2000 FAOSTAT database, 2000-2002 Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University World Production of Papaya World Yields of Papaya Region Country (1,000 mt) Region Mt/ha Africa Nigeria (748), Ethiopia (215), Congo Africa 10.2 (210) India (700), Indonesia (484) Asia Asia 11.7 Americas Brazil (1,476), Mexico (745) Americas 30.3 USA 32.9 FAOSTAT database, 2000-2002 FAOSTAT database, 2000-2002 Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Fruiting of the Papaya • Most in Hawaii USA Production »Produce 23,000 MT »Most exported to mainland USA, Canada, and Japan • Fruit hang along trunk »Production decrease since 1989 due to Papaya ringspot • Flower in leaf axils 35 30 – Most are dioecious 25 20 – Some are 15 hermaphroditic or 10 perfect flowered 1,000S metrictons 5 0 – Five classes of flowers 1965 1970 1975 1980 1985 1990 1995 2000 Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Type I or Pistillate Flower Female Papaya Flower or female flower Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Type II or Pentandria Flower Type III or Intermediate Flower Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Type IV or Hermaphroditic Hermaphroditic Papaya Flower Flower or bisexual or perfect flower Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Type V or Staminate Flower Male Papaya Flower or male flower Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Importance of Sex Inheritance of Sex • One locus, three alleles • Female – M male – Fruit is an enlarged ovary 1 – M hermaphrodite or bisexual • Male 2 – m female – Need pollen for pollination • Homozygous dominant lethal • Flower type influences – M1M1, M1M2 and M2M2 lethal – Thickness of flesh – M m = male M m = bisexual – Fruit shape 1 2 – mm = female Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Seedlings segregate for sex Hermaphroditic Variety zNeed to maximize the number of Hermaphrodite x Hermaphrodite M2 m x M2 m productive plants M2 M2 M2 m M2 m m m £Hermaphroditic varieties maximize hermaphrodites Lethal Hermaphrodite Hermaphrodite Female £Dioecious type maximize females • Plant multiple seedlings per space and rogue wrong sex - 2/3 hermaphroditic and 1/3 female Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Maximize Bearing Plants Female or Dioecious Types Hermphroditic variety • Need one male for every 12-15 females • Want hermaphroditic plants – 6-8% males • Rogue out females • Fruit is better if good pollination £ 1 per space = 67% – Pollination by wind and moths £ 2 per space = 89% £ 3 per space = 96% Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Maximize Bearing Plants Dioecious Variety Dioecious variety Female x Male m m x M1 m • Maximize females • Rogue out males m m M1 m £ 1 per space = 50% Female Male £ 2 per space = 75% £ 3 per space = 87.5% - 1/2 female and 1/2 male £ 4 per space = 93.7% Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Sex Can Change! Climatic Restrictions • Too cool, wet, and high N • Optimal temperature 22 - 26 C £ Female Sex expression shifts £ Stamens become carpel like Flavor poor if cool • Too hot, dry, and low N Die if less than -1C £ Male Die if greater than 44C £ Ovaries fail to develop Long growing season • Susceptible to wind damage Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Cultural Restrictions Diseases of Papaya • Need direct sunlight • Papaya ringspot virus – Poor flavor if shaded ·Most important • Well drained soils ·Limiting factor in many areas of world – Sensitive to waterlogging • Mildew – Susceptible to Phytophthora • Sensitive to saline conditions • Anthracnose • Root rot, Phytophthora (replant sites) • Nematodes Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Papaya Ringspot Virus 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 Tropical Horticulture - Texas A&M University Papaya Ringspot Virus Control via resistant varieties Insect Pests • UH Sunup and UH Rainbow • Fruit flies – GMOs (Genetically Modified Organism) • Webworms • White flies • Thrips • Mites • Fruit spotting bugs Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Fruit flies Papaya Varieties Two Major Types Lay eggs in fruit • Hawaiian - Solo types Larva feed ÃHermaphroditic in fruit ÃSmaller fruit, about 1 lb • Mexican or “fruta bomba” Cause rot ÃDioecious Heat treat ÃLarger fruit, up to 10 lbs to kill in fruit Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Hawaiian Varieties Mexican Varieties Hermaphroditic Solo types • Common in US markets • Locally available in many – Fruit small, firm, sweet tropical regions – Plant smaller ~ 8’ • Much larger fruit – Sex expression more stable • Flavor generally less • Series of inbred seed lines developed in intense Hawaii • Frequently dioecious – Most widely grown is “Sunrise” variety • Not as good for shipping Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Establishment Site Selection • Propagated by seed • “Virgin soil” preferred YClean off gelatinous coat • Replant sites YDry and plant immediately – High levels of Phytophthera palmivora YWarm (80 F), sterile soil – “Virgin soil” technique YGerminate in 2 weeks – Fungicide drench in planting hole YIn 10 weeks ready to transplant – Fallow of 3-5 years Tropical Horticulture - Texas A&M University Tropical Horticulture - Texas A&M University Planting Cropping Cycle • Spacing ·Single row, 8’ x 10’ • From planting begin to fruit in 10-12 ¤(435 plants per acre) months ·Double row, 6’ x 6’ x 12’ – Begins to flower in 4-8 months ¤ (850 plants per acre) – Fruit develops in 4-6 months • Multiple seedlings per space to maximize – Possible to grow as annual bearing plants • Commercially can fruit for 3-4 years – 3 to 5 plants per hole until flowering Tropical Horticulture - Texas A&M University Tropical Horticulture