Papayas are short-lived perennials; they usually live for only 5 or 6 years, and no
and soft. The roots are also soft and easily damaged.
There are two types of papaya tree: dioecious, the most common type, with male
and female reproductive organs (flowers) in separate flowers on separate plants, or
monoecious, less common, with male and female flowers separate but on the same
plant. Male plants can be recognised as soon as they flower because the flowers are
borne on long stalks. If a dioecious variety is grown, some male trees should be
grown near the females (about 1 male per 15–20 females) to ensure that pollination
occurs.
Vitamin C. Total sugars are about 9%, equal parts of glucose, fructose and sucrose.
The fruit is also the source of papain, a proteolytic enzyme extracted from the latex
of the unripe young fruit, which is mainly produced in East Africa and Sri Lanka—
see “Utilisation” and “Yield” below.
PLANTING
Propagation: normally by seed, either in nurseries or directly into the field. Farmers
can use their own seed, selected from the best trees.
Germination: takes 2–3 weeks. Air-dried seed remains viable for 2–3 years.
Soil: papaya plants will not tolerate waterlogging, though the soil should always be
moist. Ideal soils are well drained, sandy and fertile with pH 6–6.5 (classified as
having “intermediate tolerance” to soil acidity).
Roots are soft and easily damaged, so weeding around the trees should be shallow
and careful.
Seed rate: 14,000–15,000 seedlings per hectare, with about 5–7 seedlings per hole
(see next).
Spacing: 2.1–2.7 metre square grid. 5–7 seedlings or seeds are planted per station
and grown until the sex of the plant becomes apparent, in about six months. The best
female plant is left, and also one male plant per 25–100 female plants.
Rotation: when a papaya crop is finished, normally after 2–5 years, an unrelated
crop should then be grown to minimise the build-up of nematodes and/or root rots.
GROWTH CONDITIONS
Growth period: first fruit in 9–14 months, then can live for up to 25 years, though
commercially they are normally only grown for 3–5 years. Papain is normally
extracted for only 2 or 3 years.
Temperature: the plant is killed by frost, and low temperatures lead to tasteless
fruit.
Rainfall: the soil should be constantly moist, so irrigation is often necessary during
dry spells. Poor drainage tends to lead to root rots.
Altitude: below 1500 m is best, though they can grow at over 2000 m. Papain is
produced at lower altitudes, normally below 900 m for commercial tapping; latex
flow decreases with altitude.
Pests: rarely a problem. Birds sometimes damage fruit. Mites can cause some
damage.
Papaya fruit is a good source of Vitamin A and also contains about 60 mg/100 g262 TONY WINCH
Depth: 1 cm.
more than 25. The trees grow rapidly, to a height of about 2–12 m; the wood is light