Papaya (Carica papaya L.) is believed to be native to southern Mexico and neighboring Central America. It is now present in every tropical and subtropical country.
The papaya is a short-lived, fast-growing, woody, large herb to 10 or 12 feet in height. It generally branches only when injured. All parts contain latex. The hollow green or deep purple trunk is straight and cylindrical with prominent leaf scars. Its diameter may be from 2 or 3 inches to over a foot at the base.
The time between planting a banana plant and the harvest of the banana bunch goes from 9 to 12 months. Banana Tree(Musa) (Mai'a) dies after it bears one branch of banana's. Unlike the infamous Redwood, there are no 1,000 year old banana trees. But all is not lost because after the banana tree bears its fruit, it grows new shoots around it's base and a brand new tree sprouts form the new growth.
Aside from a food source, banana trees are used for cattle feed, medicine, alcohol, roofs, dye, wine, packing material and vinegar. Banana trees can be found throughout the islands.
Spending millions of dollars to study the sex life of the papaya sounds like the kind of federally funded project that will get prominent sneering attention in the next report on alleged pork barrel spending. But the Hawaii Agricultural Research Center says the research is as useful to growers as it is entertaining to the general public.
The National Science Foundation agrees, and has awarded the center $2.9 million over four years to continue its research on payaya chromosomes, done by a team led by plant molecular geneticist Ray Ming.
"The sex of papayas, which can be male, female or hermaphrodite, is directly related to profitable commercial fruit production," the center said. "Papaya farmers want to produce hermaphrodite fruit, since they have the best quality and are the most productive."
Female papaya trees are not grown commercially in Hawaii due to their variable sized fruit and reduced seed content. They leave a large air space in the seed cavity, requiring greater container volume for shipping than the more slender fruit of the hermaphrodite trees.
"Dr. Ming and his team made this breakthrough discovery of a primitive Y chromosome while conducting genetic studies to map the sex-determining gene of papaya," said center Director Stephanie Whalen. "This has both theoretical implications and practical applications."
Hermaphrodite papaya orchards are generally established by planting five or more seeds in a single hole that are grown for four to six months before they are thinned to remove the female plants and leave a single hermaphrodite tree. This system of overplanting followed a few months later by thinning to a single tree is not only wasteful of seed, water and fertilizer, it results in more spindly plant growth and less production than if plants could be grown with optimal spacing. The cost for establishing orchards might be reduced and earlier fruit harvests might be achieved if there were a way to solve the sex segregation problem for establishing orchards with hermaphrodite plants from the start.
Detailed studies of sex chromosomes in papaya may lead to the development of methods to engineer bred-true hermaphrodite variety or to eliminate the undesired seeds or plants of a particular sex automatically before seeds are sown or seedlings are transplanted. Understanding the mechanism of sex determination in papayas may have applications in the production of crop plants such as asparagus, spinach, black pepper, yam and pistachio.
"This project and others supported by the Plant Genome Research
| Kingdom | Plantae – Plants |
| Subkingdom | Tracheobionta – Vascular plants |
| Superdivision | Spermatophyta – Seed plants |
| Division | Magnoliophyta – Flowering plants |
| Class | Magnoliopsida – Dicotyledons |
| Subclass | Dilleniidae – |
| Order | Violales – |
| Family | Caricaceae – Papaya family |
| Genus | Carica L. – papaya |