Papaya, the plant and its origins

• Small, nearly unbranched tree in tropical America: 
• Genus Carica: 22 species, all from tropical America
• 5 species having edible fruit: C. papaya, C. chilensis , C. goudotiana, C. monoica, and C. pubescens

• Grown in tropics, Hawaii as food:

• fresh fruit 
• vegetable: cooked fruit (in Peru, also leaves of C. monoica)
• sweet (dulce): cooked in syrup

• Grown in Africa, Sri Lanka, etc.
• milky latex: papain: proteolytic enzyme: meat tenderizer, clearing beer (chill-proof beer), exfoliative cytology (stomach & intestinal cancer); in the Philippines, meat is wrapped in young leaves to tenderize it

Papaya, its propagation and harvest

• Propagation mostly by seed, sometimes by cutting
• After transplanting the trees will flower about 6 months later and the fruits will mature in about 4 months. Normally a yield of 100 fruits per tree can be expected.

• The fruits can be harvested for about 1 1/2 to 2 years after which they can be topped to produce secondary branchs for more fruits.
• Harvested fruits are packed for export in a single layer in corrugated fibreboard cartons lined with low density polyethylene film, storage period of mature fruits is 3 weeks at 10o C.

Papaya, its reproduction

• All species of Caricaceae, except 3 Carica species, are dioecious.
• Exceptions are C. monoica, C. pubescens, and C. papaya.
• C. papaya:
• pistillate: stable sexual phenotype, independent of the environment

• staminate or andromonoecious (both male and hermaphroditic flowers on same plant)
• feminization of male trees by low temperatures

Papaya, its history and production

• Originated in lowlands of eastern Central America. Probably was cultivated widely in Mexico and Central America prior to 1492.
• After the conquest of the Americas, became widely grown in all tropics
• Selection for larger fruit, dioecy.
• Production in Hawaii:
• based on cultivar Solo
• pear-shaped fruits of 350-500g
• produced by hermaphroditic trees of an inbred gynodioecious strain: seeds of hermaphroditic trees produce 2 hermaphrodites:1 female

• Production in South Africa:
• based on cultivar Hortus Gold
• produced by female plants of dioecious strain: seeds produce 1 female:1 male; 10-16% of plants as male is sufficient for pollination