Carica papaya Seeds | Papaya
LATIN NAME: Carica papaya
COMMON NAME: Papaya
Plant Profile
Carica papaya is a giant herb rather than a tree, with a hollow, unbranched stem and a crown of large, deeply lobed leaves. It grows fast, fruiting within a year of sowing, and it is one of the few fruit crops that can be harvested within twelve months of planting. The fruit hangs in a spiral around the upper trunk, and it ripens from the bottom upwards.
The species is native to the lowlands of southern Mexico and Central America and is now grown throughout the tropics. It comes in three sexual forms: male plants with long-stemmed flower clusters, female plants with separate flowers, and hermaphrodite plants with perfect flowers, which are the ones grown commercially because they fruit without pollination and give uniform fruit.
Science & Biotechnology
The unripe fruit and the leaves contain papain, a cysteine protease that breaks down protein, and it is harvested by tapping the skin of green fruit and collecting the latex. Papain is used as a meat tenderiser, in chill-proofing beer and in the leather industry, and it is the reason a papaya will not set in a gelatine dessert.
The plant is also the model for sex chromosome evolution. Its sex is determined by a small region on one chromosome, and the three forms are maintained by balancing selection, since hermaphrodites are the most useful but the male is needed to pollinate some varieties. Papaya ringspot virus is the main disease, and transgenic resistance saved the Hawaiian industry in the 1990s.
Uses & Benefits
The ripe fruit is eaten fresh and the green fruit is cooked as a vegetable, and the seed is used as a spice in some districts. The latex is the commercial source of papain, and the leaf is used as a wrap for cooking and as a medicine.
In traditional medicine the leaf is used for dengue fever and the seed for intestinal worms, and the fruit is used as a digestive. The evidence for the leaf in dengue is weak, and the plant should not be used in pregnancy, since the latex and the unripe fruit have been associated with uterine contractions.
Growing from Seed
Sow fresh seed in a pot at 25 to 30 degrees, and germination is in two to three weeks. Plant out when the seedling is twenty centimetres high, and plant two or three to allow for males, thinning once the flowers show.
The plant wants full sun, rich, well-drained soil and constant moisture, and it is tender below about zero. It needs shelter from wind, since the stem is hollow and snaps. Feed it well and keep it mulched, and remove the lower leaves as they yellow, since they harbour disease. In a container, use a large pot and repot every year, since the plant grows fast.
Our Take
The fastest fruit crop in the garden and the source of papain, and a plant that needs warmth, water and shelter from wind.
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