Everything you need to know about sapota cultivation, growth and harvest. Learn about:- 1. Introduction to Sapota 2. Climate and Soil Required for Cultivating Sapota 3. Propagation and Rootstock 4. Planting 5. Training and Pruning 6. Fertilizers and Manure 7. Harvesting and Postharvest Management 8. Pest and Diseases and Physiological Disorders 9. Varieties.
Contents:
- Introduction to Sapota
- Climate and Soil Required for Cultivating Sapota
- Propagation and Rootstock of Sapota
- Planting of Sapota
- Training and Pruning of Sapota
- Fertilizers and Manure of Sapota
- Harvesting and Postharvest Management of Sapota
- Pest and Diseases and Physiological Disorders of Sapota
- Varieties of Sapota
1. Introduction to Sapota:
Manilkara zapota V. Royen (synonyms Manilkara achras (Mill.) Fosberg Achras sapota Mill.) belongs to family Sapotaceae) popularly known as chiku in India. Its other common names are – chicozapote, chicle (Mexico and Central America), nispero (Colombia), sapotille; Po – sapoti, sapota, sapotilha; En – chicle tree, sapota, naseberry; Fr – sapotille; the tree is called sapotillier or arbre a chewing-gum; Others – chiku, dilly. It is originated from Central America and widely cultivated in lowland Tropics. It is the popular fruit crop in Gujarat, Maharashtra, Karnataka, Tamil Nadu, Andhra Pradesh and Kerala.
The plant is a tree of medium to large size with a pyramidal to rounded canopy. These long-lived trees grow slowly but after many years, may reach 60 to 100 ft in height. Plant is well adapted to subtropical and tropical climates. The tree has ornamental value and may be used for landscaping. Branches are horizontal or drooping. Milky latex exudes from all tree parts. This latex is known as chicle and was used to make chewing gum.
The foliage is evergreen. Leaves are 2 to 5 in (5-20 cm) long, stiff, pointed and clustered at the ends of shoots. The leaves are pinkish when newly emerged and light green to dark green at maturity. Flowers are borne singly or in clusters in leaf axils near the tips of branches. Flowers are small, bisexual, off-white, bell-shaped, and measure about 3/8 -inch (9.5 mm) in diameter.
The fruit is a berry with a scurfy brown peel, round to oval- Fruit may be shaped or conical, 5-10 cm in diameter and weigh 75 to 1000 g. The pulp is light brown, brownish yellow to reddish brown, with a texture varying from gritty to smooth. The pulp has a sweet to very sweet, pleasant flavor. Seed number varies from 0 to 12.
Seeds are dark brown to black, smooth, flattened, shiny, and 1.9 cm long. When fruit reaches maximum size, it may be picked and allowed to ripen off the tree. From experience, one can judge maturity of fruit of a particular variety or selection by its size and appearance.
The fruits are nutritious and mostly eaten as fresh fruit. Sherbets, milk shakes and ice cream can be made from fresh pulp. Chicle, the latex obtained from the bark of the tree, was for many years the principal ingredient of chewing gum. Because of their beauty and tolerance to neglect, sapota trees may also be used as an ornamental for landscaping.
2. Climate and Soil Required for Cultivating Sapota:
Sapota are adapted to tropical and warm sub-tropical climates and need warm (10°-38°C) and humid (70% relative humidity) climate where it flowers and fruits throughout the year. However, if taken to subtropics or higher elevation like in Punjab and Haryana, it gives only one crop from summer flowering in April and May. Under moisture-stress also, it produces one crop only.
Young trees have been observed to defoliate or decline due to lack of water; therefore young trees should be watered periodically during dry periods. Mature trees are tolerant of dry soil conditions.
However, for optimum fruit production and quality, periodic irrigation during long dry periods is recommended from flowering through harvest. In the home landscape, well established sapota trees generally do not require regular watering to produce satisfactorily.
The plants are well adapted to a wide range of soils but grow best in well- drained, light soils. Trees are especially well adapted to the rocky, highly calcareous soils. Although sapota trees are moderately tolerant of occasional flooding or excessively wet soil conditions, they will not perform well in poorly drained soils.
Plants grow well near the seashore, indicating a good tolerance to sea salt spray. Their tolerance to saline soils and irrigation water is not known. Typical symptoms of salt stress include marginal and tip necrosis of leaves, leaf browning and drop, stem dieback, and tree death.
3. Propagation and Rootstock of Sapota:
Through Seeds:
Seeds can be used for propagation and are used for selection of superior types, they should not be used for home plantings. Sapota is propagated through seed, which has been the basis of its variability in India.
Air Layering and Cuttings:
Marcottage (air layering) has not been an effective propagation method. Side veneer and cleft grafting on to seedling sapota rootstock are the most common grafting methods. Chip budding can also be used. Scions or bud sticks are chosen from young terminal shoots. Cover the grafted scions completely with grafting tape. The best time to graft is late summer and early fall.
Top working undesirable mature sapota trees may be accomplished by cutting trees back to a 3-ft-height (1-m) stump, white washing the entire stump and then veneer-grafting several new shoots when they reach ½ inch (13 mm) in diameter or larger.
Rayan is used as rootstock. Air-laying and softwood cuttings after treating them with IBA (2,000 ppm) are successful methods of propagation. However, plants raised through air-layering or cuttings establish poorly and are vulnerable to wind damage. Plants develop through air-layering perform better in shallow soils in west-coast.
For air-layering, 1-2 years old 45-60 cm long juvenile matures shoots of pencil thickness with plenty of healthy dark green leaves are selected. On the base of such shoots a ring of bark (2.5-3 cm wide) is removed on which IBA + NAA (10,000 ppm) each in lanolin paste is applied, covered with rooting media like sphagnum moss, vermiculite or garden soil and wrapped with plastic. Roots will develop in 3 months, and then layers are slowly separated and are established in nursery. They are planted in the next season.
4. Planting of Sapota:
Since sapota is a crop of warm and humid tropics, it can be planted in any season provided irrigation facilities are available. But it is beneficial to plant the grafts in beginning of the rainy season. In areas having heavy rainfall, it can be planted in September. In light soils, pits of 60 cm x 60 cm x 60 cm size, whereas in heavy and gravely soils pits of 100 cm x 100 cm x 100 cm size are made in April-May and exposed to sun for 15 days.
Although plants grow slowly, trees that are not pruned eventually need a lot of space because they will develop a large canopy. Plants in the home landscape should be planted 7.6 m or more feet away from the nearest tree and/or structure. Trees planted too close to other trees or structures may not grow normally or produce much fruit due to shading.
Sapota trees should be planted in full sun for best growth and fruit production. Select a part of the landscape away from other trees, buildings and structures, and power lines. Remember sapota trees can become very large if not pruned to contain their size. Select the warmest area of the landscape that does not flood (or remain wet) after typical summer rainfall events.
The pits are filled with top (30 cm) soil mixed with equal quantity of well- rotten compost or farmyard manure, 3 kg superphosphate and 1.5 kg muriate of potash, all the sides of the pits are dusted with 5% BHC dust. The filled pits are left to monsoon rains.
The pits are planted with scion in the direction of heavy wind to avoid damage. Planting is done in the evening to avoid sun heat and then watered lightly. Young plants should be protected from sun by covering them with dry grass in top except the south-east for sunlight.
5. Training and Pruning of Sapota:
Young Trees:
The development of a strong limb framework is important to allow sapota trees to carry large crops of fruit without limb breakage. If the tree is leggy and lacks lower branches, remove part of the top to induce lateral bud break on the lower trunk. In addition, shoot tip removal (1 to 2 inches) of new shoots of about 3 ft in length, once or twice between spring and summer will force more branching and make the tree more compact. Remove any limbs that have a narrow crotch angle because these may break under heavy fruit loads.
Mature Trees:
As trees mature, most of the pruning is done to control tree height and width and to remove damaged or dead wood. Trees should be kept at a maximum of about 3.7- to 4.6-m. If the canopy becomes too dense, removing some inner branches will help in air circulation and light penetration. Another pruning objective is the removal of dead, damaged or diseased branches. Low branches should not be cut however, unless they touch the soil. Cultural practices e.g., picking, spraying, and pruning are easier on small trees.
For mature, very large sapodilla trees in the home landscape that may pose a risk of damaging adjacent buildings or trees, we recommend a professional arborist provide the pruning services. Make sure the arborist is licensed and has insurance and knows the local ordinances pertaining to fruit tree pruning in your area.
6. Fertilizers and Manure
of Sapota:
Sapota is not demanding in its fertilizer requirements. After planting, when new growth begins, apply 113 g of a young tree fertilizer such as a 6-6-6-2 (Nitrogen: Phosphate: Potash: Magnesium) with minor elements with 20 to 30% of the nitrogen from organic sources. Repeat this every 6 to 8 weeks for the first year, then gradually increase the amount of fertilizer to 227 g, 341 g, 454 g as the tree grows. Use 4 to 6 minor element (nutritional) foliar sprays per year from April to September.
Sapota trees generally do not develop iron deficiency, even when grown in the rocky, calcareous, high pH soils of Miami-Dade County. If iron deficiency symptoms appear (chlorotic leaves with green veins), apply iron. For trees in acid to neutral soils apply dry iron sulfate at 0.25 to 1 oz per tree to the soil 2 to 4 times per year; water the iron into the ground. In alkaline soils with a high pH, drench the soil adjacent to the tree trunk with iron chelate 1 to 2 times per year from June through September.
For mature trees, 2.5 to 5.0 lbs of fertilizer per application 2 to 3 times per year is recommended. The fertilizer mix (NPK) should also include phosphate (P2O5) and potash (K2O); use a 6-6-6, 8-3-9 or similar material. Use 2 to 3 minor element (nutritional) foliar sprays per year from April to September.
Fertilizers should be applied before the onset of monsoon in rainfed areas. However, under irrigated conditions it should be applied in 2 splits. In Zn and Fe deficiency, the requirement should be met through application of organic manures and spraying of ZnSO4 and FeSO4 (0.5%).
Weeds compete for water and nutrients. Weeds may be controlled by herbicide applications of registered materials, by hand weeding, and/or by mulching. In young orchards, weed hazard is common. Use of 2 kg Bromacil + 2 kg Diuron/ha as pre-emergence spray is effective for a period of 10-12 months.
Mulching sapota trees in the home landscape helps retain soil moisture, reduces weed problems adjacent to the tree trunk, and improves the soil near the surface. Mulch with a 5- to 15-cm layer of bark, wood chips, or similar mulch material. Keep mulch 20-30 cm from the trunk.
Mixed plantation with mango and guava should be avoided to reduce the problem of fruit-fly. Intercropping banana, papaya, pineapple and cocoa, French bean, tomato, brinjal, cabbage, cauliflower and cucurbits is recommended depending on climate and water resources.
Newly planted sapota trees should be watered at planting and every other day for the first week or so and then 1 to 2 times a week for the first couple of months. During prolonged dry periods (e.g., 5 or more days of little to no rainfall) newly planted and young sapota trees (first 3 years) should be watered once a week.
Once the rainy season arrives, irrigation frequency may be reduced or stopped. Once sapota trees are 4 or more years old watering will be beneficial to plant growth and crop yields only during very prolonged dry periods during the year. Mature sapota trees do not need frequent watering and over watering may cause trees to decline or be unthrifty.
Sapota requires irrigation at 30 days interval in winter and 15 days in summer. Adoption of drip irrigation system is also beneficial, saving 40% water with 70-75% higher net income.
7. Harvesting and Postharvest Management
of Sapota:
It is not easy to determine when the sapota is sufficiently mature to harvest. Some say the fruits are picked when they show a reddish tinge. Harvesting of large trees requires a picking pole with a cutter and a basket to catch the fruits; or workers must use ladders and twist the fruit until the stem breaks. Trees that become too tall may be topped so that the crop will be within reach. After picking, the stem is close-clipped and the fruits are packed in boxes or baskets to avoid injury.
For the beginner, fruit maturity is difficult to judge. Immature fruit may not soften for many days, may not develop optimum sweetness and flavor, and may contain pockets of coagulated latex within the flesh. Fruit picked at optimum maturity usually ripen in 4 to 10 days. If the time of fruit maturity is unknown, you may wait until some fruit drop and then begin to harvest those of similar size.
Maturity is decided on the basis of ease with which brown scruff gets of the fruit surface and development of yellowish tinge intermixed with corky-brown colour on the surface of the fruit Other indicators of maturity are fruit size, loss of peel scurfiness, and a change in skin color from brown to amber. Another test is to lightly scratch the skin; if it is tan it can be picked, but if it is green or oozes latex, the fruit is not fully mature.
The fruiting starts from third year after planting but the economic yield can be obtained from seventh year onwards. Being dimateric fruit, it improves in quality after harvesting but pre-mature harvesting leads to poor quality. On the other hand, fruits harvested late soften quickly resulting in spoilage during handling and transport.
At maturity, the brown scurf on the fruit surface is replaced by yellowish corky brown colour. The absence of green tissues and latex also indicates maturity. The fruits are picked by hand or harvested with special harvester which has a round ring with a net bag fixed on a long pole.
In general a fully mature tree of 10 to 15 years of age yields 1000-3000 fruits/tree depending on the variety and management practices.
Sapodilla trees may have harvestable fruit year round, though there is a main season for each cultivar. The average yield per plant of about two years old may be around 1,000 to 1,500 fruits (100 to 150 kg). As the season for each cultivar advances, the ripening time decreases. Ripe fruit may be stored in the refrigerator.
The fruits are highly perishable and they undergo rapid ripening changes within 5-7 days during which the fruits become soft, sweet and develop excellent aroma with decline in tannins, latex sapotin, aldehydes and acidity. The changes are associated with increase in production of ethylene, rate of respiration, catalase, peroxidase and PME activities. These changes can be regulated through chemicals, temperature and storage gas composition.
Harvested fruits should be cleaned of latex and scurf by washing in clean water to make them look attractive. Shelf-life can be extended by dipping the dipped in GA 300 ppm + Bavistin 1,000 ppm solution at prepacking stage. For uniform and rapid ripening Ethphon (1,000 ppm) can be utilized at 20°- 25 °C. Modified storage with 5-10% (c/c) CO2 can be employed for long storage (21-25 days). Refrigerated vans (12-13°C) should be utilized for long distance and export markets.
Studies on postharvest changes in sapota (Achras sapota L.) at ambient storage conditions was made by Singh et al., (2001) of Central Agricultural Research Institute, Port Blair (Jour. Appl. Hort., 2000, 2(1)31-33) during ripening of four sapota (Achras zapota [Manilkara zapota]) cultivars, viz. Cricket Ball, Ever Bearer, Bangalore Giant and Calcutta Round, at ambient temperature (25-30 deg C) and relative humidity of 70-90%.
They recorded significant changes during storage in physico-chemical constituents of all the cultivars studied. The ripening process started first in Ever Bearer and its total soluble solid contents, total sugars, reducing sugars and ascorbic acid accumulation declined after 4 days. All the cultivars had a storage life of 6 days whereas Ever Bearer could only be stored for 2 days at ambient temperature.
Sapota fruit respiration pattern follows that of a climacteric fruit. Respiration may be slowed by growth retardants such as gibberellic acid (GA), kinetin and silver nitrate.
Sapodilla may be stored under controlled conditions for a short period of time. The optimum cold storage is obtained at 35° to 38 °F with a relative humidity of 85%-90%. Under these conditions, fruit could be stored for up to eight weeks. Holding the fruit at 4°C before storing at 20°C extend the storage life of the fruit although exposure to 4°C for longer than ten days resulted in chilling injury.
Storage of sapota under high CO2 concentrations provided CO2 was less than 20% (v/v), and low ethylene concentrations, also prolonged the storage life of the fruit. Upon reaching full maturity, sapodilla fruit deteriorates rapidly, lasting only 2 to 10 days.
Various growth retardants are used to control postharvest changes. Application of GA, kinetin, and silver nitrate result in up to a two-day increase in storage time due to reduction of catalase and pectin methyl esterase activity, and reductions in respiratory activity and ethylene production. The application of these compounds appears to reduce the rate at which fruit ripens as well as affecting fruit quality characteristics such as total sugars, acidity, ascorbic acid, and starch.
Both wax coating and 2, 4-Dichloro-phenoxy acetic acid (2, 4-D) can retard the ripening process in sapota, while 2-Chloroethyl phosphoric acid (ethril) greatly accelerate ripening. Polyethylene bags can also reduce weight loss in sapota by about 50%.
8. Pest and Diseases and Physiological Disorders
of Sapota:
Because of the high moisture and nutrient content of the fruit, sapodilla is especially prone to postharvest diseases. Common diseases include sour rot (Geotrichum candidum), Cladosporum rot (Cladosporum oxysporium), and blue mold rot (Penicillium italicum).
Benlate (methyl-N-1-butylcarbomoyl) is a commonly used fungicide for postharvest treatment of sapota, best to control both fungal and bacterial pathogens of sapota. Although several non-chemical treatments have been tested, none have proven to be successful against postharvest pathogens of sapota.
1. Wilt or die-back is common where sapota cultivation is being extended to traditionally rice-growing regions.
2. The shape of fruit is related with number of seeds in it which depend on conditions for pollination at anthesis. The cultivation of sapota in areas with extreme summer temperature should be avoided.
3. Sometimes fruits do not develop into their normal shape but develop a depression or furrow towards the calyx-end after heavy rainfall and high intensity of irrigation. Therefore over-irrigation should be avoided.
4. The fruits exposed to intense sunlight do not ripen uniformly, developing corkiness during winter, probably due to killing of hydrolyzing enzymes by alternating moisture accumulation and heating of fruit surface in winter.
9. Varieties of Sapota:
There have been a number of new cultivars developed in USA, India, the Philippines, Mexico and Venezuela. Varieties with good horticultural characteristics should have high yield, moderately large to large fruit, and a smooth, sweet and aromatic pulp with little or no grittiness.
1. Alano – United States (Hawaii). The fruit is conical to round, skin light brown, smooth, 115-250 g. Pulp is smooth to slightly granular, very good to excellent, season- Nov.-June.
2. Betawi – Indonesia. Fruit is conical, 315 g, pulp light amber – yellow, slightly granular very good, juicy, Season- late Dec.
3. Brown Sugar – United States. Fruit is round to ovate, skin light brown, moderately scurfy, 133-170 g, brown, slightly granular, Season- May-Sept.
4. Gonzalez – Philippines. Fruit is round to oval, skin very light brown, slightly scurfy, 260 g, pulp is light brown to brown, smooth, very good to excellent, Season- Nov.-April.
5. Hasyá – Mexico. Fruit is oval to slightly conical, skin light brown, moderately scurfy, 365 g, pulp is brownish red excellent, Season- Nov.- June.
6. Makok (dwarf) tree – Thailand. Fruit is conical, skin light brown, slightly scurfy, 140 g, pulp is light brown to slightly greenish- red, smooth very good, Season- May-Nov.
7. Modello – United States. Fruit is elliptic to ovate, skin light brown, moderately scurfy, 340 g pulp, is whitish to tan, smooth, Season: Feb.- May.
In India, Kalipatti is grown in Gujarat and Maharashtra.