Dept of Agriculture Development 
SFAC KeralaWashington, Honey Dew, Coorg Honey Dew, Solo, Pusa Dwarf Surya, Co-7, Pusa Nanha, Pusa Giant, Co-2 and Co-5 are suitable for papain extraction.
The best time for raising papaya seedlings is from February to March
Papaya is propagated almost entirely by seeds
Two month old seedlings are transplanted in the main field in May-June at a spacing of 2 x 2 m. Pits of size 50 x 50 x 50cm are taken and filled with topsoil. Male plants are removed as soon as they flower and the female and hermaphrodite plants are retained. In pure female plantations, one male plant is retained for every 10 female plants. Seedlings are shaded to protect them from excessive sunlight until they establish. In hermaphrodite or monoecious types male plants may not be required.
Organic manure may be applied at the rate of 10 to 25 kg / plant / year at the onset of southwest monsoon in basins around the plant. Each papaya plant should also be supplied with 40 g N, 40 g P2O5, and 80 g K2O at every two month interval.
The crop should be irrigated in summer. The ring system of irrigation is better for papaya than the basin system because the ring system prevents irrigation water coming into contact with the stem, thus preventing collar rot.
Keep the papaya plot free of weeds. Two hand-diggings, one in the beginning of the rainy season and another in January - February are necessary. When papaya is grown as the main crop, vegetables can be profitably cultivated as intercrop for about six months from planting of papaya seedlings.
The seedlings flower and set fruit within 3-5 months after transplanting. The number of fruits harvested per tree per year varies from 25 to 30. Fruits showing streaks of yellow colour are harvested. Although papaya trees bear flowers and fruits continuously for many years, it is not economical to retain the trees after 2.5 to 3 yrs.
Papain is an active enzyme present in the latex or milky secretion of papaya plants and immature fruits. Half to three-fourth matured fruits (about 70 to 100 days from fruit set) are preferred for papain extraction. Tapping of fruits can be done early in the morning by giving longitudinal skin-depth incisions (0.3cm) on the surface of the fruits from the stalk end to tip. Stainless steel blades or knives or bamboo splinters are used for incising papaya fruits. The milky latex is collected in arecanut spathes or aluminium or glass vessels.
The incisions are repeated in two or three subsequent occasions at 3 to 4 days intervals. The latex collected in this way is dried in the sun or in an artificial drier at 50-55°C. A small quantity of potassium metabisulphite is added to the liquid latex to extend the storage life of papain. The dried latex can be stored in airtight polythene or glass containers for a period of six months. Tapped fruits are equally tasty as untapped fruits, although impaired in appearance.
