PAPAYA – Agronomy

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Papaya being a tropical fruit grows well in the mild sub-tropical regions up to 1,000 m above sea level. Night temperature below 120-140 C for several hours during winter season affects its growth and production severely. It is very much sensitive to frost, strong winds and water stagnation.

Generally papaya grows well in the tropical and sub tropical climates. It performs well in regions with even rainfall of 1200 mm to 1500 mm throughout the year without dry spell with temperature of 21 – 33°C. It should not be planted in areas with strong wind because the plant is shallow rooted and easily lodged. In Phillipines local materials such as ipil-ipil and madre de cacao are planted as windbreaks.

Soil Suitability: Papaya prefers fertile, deep, well drained sandy loam soil with pH ranges from 5.5 to 6.7 for normal growth and production. It also requires good soil drainage.

Planting Material: Papaya is commercially propagated by seed and tissue culture plants. Get seed from selected fruits produced by controlled pollination to ensure the quality and uniformity of the plantings. The seeding rate is 250-300 g/ha. The seedlings can be raised in nursery beds 3m long, 1m wide and 10 cm high as well as in pots or polythene bags. The seeds after being treated with 0.1% Monosan (phenyl mercuric acetate), ceresin etc. are sown 1 cm. deep in rows 10 cm. apart and covered with fine compost or leaf mould. Light irrigation is provided during the morning hours. The nursery beds are covered with polythene sheets or dry paddy straw to protect the seedlings. Seedlings of about 15-20 cm. tall are chosen for planting in about two months.

The rooting or cutting techniques have been practiced inSouth Africa. This technique is functioning to eliminate variability in certain clones So that their performance can be more accurately. The commercial cultural “Honey Gold” is grown entirely from cuttings. Once rooted, the cutting are planted in plastic bag and kept under mist for 10 days, and then put in a shade house for hardening.

Budding Experiment, Forkert and Chip Methods, has been practiced inTrinidad. It is vegetative propagated selected strain deteriorate steadily and is worthless after 3 or 4 germination.

While grafting techniques in papaya, has been practiced inHawaii. Solo grafted onto Dwarf Solo was reduced in vigor and productivity. Dwarf Solo grafted onto Solo improved performance.

The papaya tissue culture has been practiced among the Indian scientist. They making colorimetric test of leaf extracts have had 87% success in identifying seedlings as female, 67% male bisexuals grouped together. Efforts have been made to determine the sex of seedlings in the nursery. Recommended nursery soil mixture is 25% sand, 25% organic manure (preferable cow dung or blood and bone meal) and 50% top soil mixed by volume.

Land preparation: For open field planting, the land is plowed and harrowed twice. An elevated plot along the row is made by plowing on barring with two passes on each side. This will insure proper irrigation and drainage. Organic fertilizer and manure should be spread and incorporated in the soil during land preparation.

Planting System: Planting of papaya is carried out at the commencement of a rainy season. Prior to that, holes are dug in the summer months about a fortnight before planting. The seedlings are planted in holes of 60x60x60 cm. size. The holes are filled with top soil along with 20 kg farmyard manure. Tall and vigorous varieties are planted at greater spacing while medium and dwarf ones at closer spacing. In India a spacing of 1.8 x 1.8 m. is normally followed. However higher density cultivation with spacing of 1.5 x 1.5 m/ha or a much closer spacing of 1.2 x 1.2 m. for cultivar Pusha Nanha is adopted for high density planting, accommodating 6,400 plants/ha to enhance the return for the growers.

In Malaysiathe rectangular planting system with planting distance of 2.7m x 1.8m accommodating 2000 plants/ha is recommended. Planting holes of 0.3m x 0.3m x 0.3m in size is dug and allowed to weather for 2-4 weeks before planting.

Plant care and maintenance: There are no reliable characteristics to distinguish male, female and hermaphrodite plants until they bear flowers. This is the reason why 2-3 plants are recommended to be planted and allowed to grow on each hill until flowering. The plants bear flower in 6 months after germination. When the flowers appear and the sex determined, remove the male and undesirable plants. Leave only on vigorous hermaphrodite of female plant.

1. Remove side growths along the leaf axles that occur during the early stages of plant growth. They compete with plant nutrients needed by the plant. These areas can also harbor pests and diseases.
2. Always exercise general sanitation. Clean fields minimize spread of pests and diseases.
3. Regularly remove diseased, senescent and dried leaves. These areas provide good habitat and unnecessary source of pests and diseases.
4. Cut down and carry away blown down and diseased trees from the field. Diseased leaves and fruits will be removed and buried or burned.

Weed control: Weeds are host and vector/carrier of pest and plant diseases.

Weeding is very necessary for papaya, to sanitize its immediate environment from insect pests that climb the trunk like ants carrying aphids and scales. It will remove competitor for plant food nutrients in the soil.

1. Round weed newly established fields. Clean an area of one meter radius around the base of the plant.
2. Avoid herbicides as much as possible since they kill microorganism in the soil that helps enhance decomposition of organic wastes into fertilizer and plant food.
3. Slash tall weeds in between the rows or pass them with harrow to keep them down.
4. Maintain the cleanliness of the field at all times.
5. Always remember that weeds can reduce by 25% your production.

Irrigation Requirements: Generally papaya is irrigated to encourage development and healthy growth especially during the early stage of plant growth. The lack of moisture for papaya trees produced drought-stress symptom. The papaya may drop flowers, leaves and young fruit and also produce small fruit of low sugar content. To minimize flower drop or fruit drop, irrigate the plants before the soil gets dry. Weekly watering is advisable during dry months. Avoid too much watering to prevent fungal infection. See to it that soil is aerated from time to time through shallow cultivation to avoid root rot.

Drip System: Generally, it is recommended for papaya. This system ensures a uniform distribution of water. An irrigation application rate 4 to 5 gal/plant at 2 to 3 day intervals can conservatively increase yield by about 20 percent over rain-fed crop yield.

Fertilization: Plant nutrition should constantly be monitored and needed fertilizer is applied on time. The best fertilizer is the organic compost mixed with the soil during land preparation. This should be augmented with chemical fertilizers high in potash and contain trace mineral elements. Boron is one critical element that needs to be always present as it is needed for flower fertilization and fruit development; 20-40 grams Boron is adequate for each plant. It is recommended that small amount of fertilizer be applied at frequent intervals. For young papaya plants, apply 0.125 kg of a complete fertilizer (NPK) with the amounts increasing as trees become larger at every 14 days. When the papaya trees reach the age of 7 to 8 month old, apply 0.5 kg to 1.0 kg of complete fertilizer every other month while for the minor elements applied once a month. Minor elements include manganese and zinc applied to low soil pH (7 or less). Foliar applied for plants growing in high pH soils. FeSO₄ may be applied to ground for plants growing in low pH soils.

Below this are the recommended fertilization programmed:

Pruning: Basically, papaya trees do not require pruning. It is because their main growing point is terminal and branched trees generally do not produce as well. Some growers pinch the seedlings or cut back established plants, therefore, to encourage multiple trunks for the tree. To facilitate the growth and fruiting of the tree, selecting 1 or 2 of the most vigorous shoots and removes it from the others. Besides that, removal of dead leaves is a good practice and results in less scarring of the fruit from the base of the leaf petiole, it helps reduces disease and insect problems.

Mulching: For the papaya mulching, the mulching can be practiced within 2 – 6 inch (5-15 cm) layer of bark, wood chips or similar mulch materials. This is the benefits of mulching practices: retains soil moisture, reduces weed problems adjacent to the tree trunk and improves the soil near the surface.

1. Chong, S.T.,  R. Prabhakaran and H.K. Lee. ISHS Acta Horticulturae 787: International Workshop on Tropical and Subtropical Fruits.
2. Lamberts, M. and J.H. Crane. 1990. Tropical fruits. p. 337-355. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press,Portland,OR.
3. Morton, J. 1987. Papaya. p. 336–346. In: Fruits of warm climates. Julia F. Morton,Miami,FL.