Pawpaw/Carica Papaya
(unranked) - Angiosperms
(unranked) - Angiosperms
(unranked) - Eudicots
(unranked) - Rosids
Order - Brassicales
Family - Caricaceae
Genus - Canca
Species - C.papaya
It is native to the tropics of Americas, perhaps from southern Mexico and neighboring central America. It was first cultivated in Mexico several centuries before the emergence of the mesoamerican classical civilizations.
Description
The papaya is a small, sparsely branched tree, usually with a single stem growing from 5 to 10m (16 to 33ft) tall, with spirally arranged leaves confined to the top of the trunk. The lower trunk is conspicuously scarred where leaves are large, 50-70cm (20-28 in) in diameter, deeply palmately lobed, with seven lobes. All part of the plant contain latex in articulated lactifers. Unusually for such a large plant the trees are dioecious. The flowers are 5-parted and highly dimorphic, the male flowers with stamens fused to the petals. The female flower have superior ovary and five contorted petals loosely connected at the base. Male and female flowers are borne in the leaf axils, the male multi flowered dichasia, the female flowers is few-flowered dichasia. The flowers are sweet-scented, open at night and are moth pollinated. The fruit is a large berry about 15-45cm (5.9-17.7 in) long and 10-30cm (3.9-11.8 in) in diameter.It is ripe when it feels soft (as soft as ripe avacado or bit softer) and it's skin has attained an amber to orange hue.
Origin and distribution
Papaya is native to Mexico and extends to south American and has become naturalised throughout the Caribbean islands, Florida and several countries of Africa. Additional crops are grown in India, Australia, Malaysia, Indonesia, the Philippines, Thailand and U.S state of Hawaii.
Cultivation and production
Papaya plants grow in three sexes: male, female, hermaphrodite. The male produces only pollen, never fruit. The female will produce small, inedible fruit unless pollinated. The hermaphrodites can self-pollinate since it's contain both male stamens and female ovaries. Almost all commercial papaya orchards contain only hermaphrodites.
Viruses
Papaya ringspot virus is a well-known virus within plants in Florida. The first signs of the virus are yellowing and vein-clearing of younger leaves, as well as mottling yellow leaves. Infected leaves may obtain blisters, rough or narrow, with blades sticking upwards from the middle of the leaves. The petioles and stem may develop dark green greasy streaks and in time become shorter. The ringspots are circular, c-shaped marking that are darker green than the fruit itself. In the later stages of the virus, the markings may become gray and crusty. Viral infections impact growth and reduce the fruits quality. One of the biggest effects that viral infections have on papaya is taste. As of 2010 the only way to protect papaya from this virus is genetic modification.
The papaya mosaic virus destroys the plant until only a small tuft of leaves are left.The virus effects both the leaves of the plant and the fruit. Leaves show thin, irregular, dark-green lines around the borders and clear area around the veins. The more severely affected leaves are irregular linear in shape. The virus can infect the fruit at any stage of it's maturity. Fruits as young as 2weeks old have been spotted with-dark green ringspots about 1inch in diameter. Rings on the fruit are most likely seen on either the stem end or the blossom end. In the early stages of the ringspots, the rings tend to be many closed circles, but as the disease develops the rings will increase in diameter consisting of one large ring. The difference between the ringspots and the mosaic viruses in the ripe fruit in the ringspots has mottling colors and the mosaic does not.
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