Guyabano or soursop is one of the minor crops that is gaining popularity because of its economic uses. It is a nutritious fruit, rich in ascorbic acid, potash, phosphorous and calcium. The edible portion is 70% with food energy of 63 calories and the sugar content ranges from 4 to 14%. Because of its many economic uses and great demand in processing industry especially in producing guyabano drinks, expansion and more production should encourage to meet its demand. Consequently, the crop is now gaining its prospect in the world market.
Based on BAS crop statistics of 2003; a total land area of 3,016 has. were planted to guyabano with the following as the five leading producing regions: Western Visayas (705 has.); Region !V-A (643 has.); Cagayan Valley (400 has.); Central Visayas (169 has.); and Central Luzon (165 has.).
Guyabano is a potential crop with varied economic uses. The nature green fruits are used as a vegetable and for making sweet meats, while the ripe one is eaten off hand or as dessert. Its juice is used for flavoring ice cream, sherbets, canning and for preparation of refreshing drinks. It may also be processed intro preserve, candies, jam and jelly. Guyabano also posses some medicinal properties. The trees maybe used for landscaping and for shade.
There are two strains presently grown.
Aguinaldo – Fruit, 1kg; peel, yellow green; flesh, juicy, sub-acid, 78% of fruit weight; seeds, 70 per fruit
Davao – Fruit, 1.7 kg; peel, light green; flesh, moderately juicy, pleasantly sub-acid, 82% of fruit weight; seeds, 82 per fruit.
Seed Preparation and Germination
The seeds to be used as source of seedlings for planting should be obtained from outstanding mother trees. The mother plant should be hardy, prolific and regular bearer and its fruits be medium-sized to large, well formed, few seeded and excellent quality. Seed extracted from the fruit should be cleaned thoroughly in tap water and allowed to air dry. They maybe stored for quite sometime but it is best to plant them without delay. They are sown in seed boxes or flats containing fine and/or sandy soil of about 2.5 cm distance and 1 cm deep. The seedbed is provided with shade and watered regularly to keep the medium moist at all times. Fresh seeds germinate from 20 to 30 days with 85 to 90 percent germination.
Care and Transplanting of Seedlings
The seedlings are watered regularly and sprayed with insecticide and fungicide if insect pests and diseases become a problem. When the young plants are 3-4 inches high or when the first set of leaves has matured, they may be transferred in individual container like plastic bags. The soil medium should be clay loam preferably mixed with sand or compost. The newly transplanted seedlings are placed under partial shade and, when well established, they may be exposed to the sun for hardening. They are regularly watered to ensure continuous growth and to protect against pests and diseases. Seedlings are ready for field transplanting when they are 6 to 8 months old or about 15 cm tall.
The guyabano is usually propagated by seeds. However, selected trees of inherent characters may also be propagated asexually by marcotting, inarching, grafting and budding.
Soil and Climate Requirements
Soil – the plant thrives in any kind of soil but it grows well in loose, fairly rich, deep loam and well drained soil.
Climate – guyabano culture require a warm, dry climate during the blooming period to get a good fruit set. After this, almost a continuous light rainfall is necessary.
Elevation – it thrives well from sea level up to 300 meters above sea level.
pH – it grows better on soil with pH ranges 6.1 to 6.5.
In preparing the land be sure to have a ready supply of compost or organic manures for basal application in order to improve the soil texture. The land should be plowed two or three times followed by harrowing with the incorporation of organic manure until the excellent condition for planting is attained. For newly opened land, under brushed branches and twigs should be burned before the holes are dug. For backyard planting, a hole wide and deep enough to accommodate the ball of the root system of the seedlings is dug just before planting. The field is laid out by putting stakes following the desired distance of planting which ranged from 4 to 7 meters each way. Holes are dug at the positions occupied by the stakes. A hectare at this planting distance would require 204 – 625 planting materials.
Planting – may be done in any month of the year provided the soil is not so dry and there is good supply of water for the newly planted seedlings. Holes, 2 x 2 x 2 ft. are dug and refilled with top soil and compost. Water the young plants soon after setting them in the field. The newly planted seedlings should be protected from strong wind and bright sunshine. Mulch each young tree before the dry season begins and irrigate whenever necessary during the dry months.
Cultivation– the area around the base of the tree should be kept free of weeds by regular shallow cultivation. Brush weeding and shallow cultivation of the soil below the periphery, of its foliage to a depth of about 3 cm at the time of fertilizer application are sufficient.
Fertilization – generally, fertilizer application is beneficial in promoting plant growth and makes the young tree grows strong and sturdy. It also help increase fruit production. The application of 100 – 150 grams Ammonium Sulfate a month after planting and an equal amount six (6) months after or at the end of the rainy season is recommended. The quantity is increased every year until the tree start to bear fruit at which time, 250 – 300 grams of complete fertilizer is applied. This amount also increased in each succeeding year of fruiting from 1.5 to 3.0 kg. of complete fertilizer (14-14-14) plus 200 – 300 grams of Muriate of Potash (0-0-60).
When branching is excessive and other branches are defective growing downward or interlacing with others, pruning is necessary. Such branches together with water sprouts should be pruned. Dried twigs and disease branches should likewise be pruned to avoid further infestation and disease infection. This practice improves aeration on the interior of the tree, permits sunlight to fall on the whole tree thus stimulate better fruit yield.
While the trees are still young, weeds could grow in the spaces between plants and compete with food nutrients. Hence, to give full utilization of the land, intercropping the orchard is usually accorded. The perennials that may be intercropped with guayabano are banana, coffee, cacao, blackpepper, mulberry and/or citrus. It may also be planted as an intercrop to bigger fruit trees such as avocado, starapple, durian, mango, jackfruit, rambutan, santol and under coconut.
Intercropping with such annual crop as vegetable, legumes, cassava, ginger and gabi for the first 3 years after planting would be profitable and will help put down growth of weeds aside from the added income.
When intercrops are no longer grown, the orchard should be planted to perennial legumenous cover crops such as centrocema and calopogonium.
Guyabano can tolerate dry soil condition better than other fruit trees. However, during the dry season with prolonged drought, plants may shed too much leaves and needs water application. For the rapid growth of the trees irrigation is needed due to their relatively shallow root system.
Guyabano is attacked by a number of pests, such as:
Root grubs – they attacks the roots and during the advance stages causes the wilting of the whole plants. Grubs can be controlled by drenching with chlordane at the base of the tree.
Mealy bugs – they suck the sap of young leaves and fruits. Attacked leaves turns yellow and the plant become stunted in growth. These insect pests can be controlled by spraying Malathion, Methyl Parathion or Azodrin at manufacturer’s recommended dosage.
Carpenter Moth Larvae – they bore into the inner part of the wood where they feed and grow. Damage may be reduced by collecting and burning of infested twigs.
Scale Insects – they are commonly found feeding on the under surface of the leaves, and suck the sap causing the leaves to dry up. These pests can be controlled by spraying the tree with Malathion at recommended dosages.
Oriental fruit fly – the maggot eat up the tissue of the fruit leading to decay. Bagging the fruits may help reduce fruit fly damage. Kalingag powder may be used to attract fruit flies mixed with insecticide and kill the insects.
Nest Building Ants – the ants do not damage the tree but they protect the scales and mealy bugs and get nourishment from the secretion of this insects. Ants may be controlled with the same insecticide sprayed for the above pests.
The following are the major diseases:
Root Rots – it infects and causes the decay of the roots eventually leading to the collapse and death of the tree. The diseases trees should be cut down and burned.
Pink Disease – causes twigs and branches to collapse and die. The presence of the disease is manifested by a fungal growth on infected areas. The disease may be controlled by collecting and burning infected twigs, branches, and leaves, and spraying the tree with copper fungicide.
Anthracnose – flowers and fruit may be affected by the anthracnose fungus and fall. This disease may be controlled by spraying the tree with fungicide such as Maneb, Captan, or Vitigran Blue. The same fungus can also cause damage to seedlings and shoot of bearing trees.
Harvesting and Storage
The guyabano trees bear fruits in 3 – 5 years after planting. They flower most months of the year but the peak of flowering is May and June, and the fruit ripens in November and December.
The guyabano fruits should be harvested when they are fully matured. They are considered mature when they turn shiny green or yellowish green and their spines are set far apart. If the fruits are picked prematurely, they will ripen but their quality is poor. On the otherhand, fruits left to ripen on the tree are often attacked by birds and bats if they do not first fall to the ground.
The fruits on a tree do not mature at the same time which therefore requires selective harvesting. Fruits for vegetable purposes are usually harvested when they are only about 4 months old.
Fruits are harvested by bending the branch or climbing the tree and twisting each fruit off its peduncle with or without use of knife. The harvested fruits are then placed in a bamboo baskets lines with soft materials, such as newsprints or rice straw. Fully mature fruits ripens in 3 to 5 days after harvest. Ripe fruits are easily injured because of their soft and tender skin, and should be handled with great care. The fruits are transported to nearby markets soon after harvest.
Fruits for the factory are placed in a bodega under ordinary room temperature and allowed to ripen with firmness until they are ready for processing/preservation.
On the otherhand, ripe fruits may be held 2 or 3 days longer in refrigerator, but the skin blacken and become unsightly. However, the flesh and flavor are not affected.
Processing and Utilization
Preservation/utilization of fruits has been getting widespread attention not only on its increasing acceptability in the food market but also because of its potential as a means of generating an export. The various preservation of guyabano was briefly described in the following procedures.
Guyabano Juice – after washing sound ripe fruits, they are blanched for 3-4 minutes in boiling water. They are cooled in water, peeled and their inner core removed. They are cut into 5 cm square pieces. One cup water is added to 1 cup fruit heated at 800C for 3 minutes or until the fruit is soft enough to squeeze of the juice. The juice is pressed through a muslin bag while hot. The juice from the residue is extracted for the second time with the same amount of water. The two extracts are mixed and sugar is added to taste. The juice is poured into jars and exhausted before sealing to 820C (approximately 15 minutes from boiling time). The jar is sealed immediately, sterilized in boiling water for 10 minutes, cooled and stored.
Guyabano Preserve – mature but firm fruit is peeled sliced about 1 cm thick using stainless steel knife, and soaked in water. It is blanched in boiling water for 5 minutes cooked in syrup (2 parts sugar and 1 part water), and soaked in syrup overnight. It is again boiled for 30 minutes until thick, drained and packed in preserving jar. The jar is filled up with syrup, half-sealed, sterilized for 25 minutes in boiling water and sealed completely.
Guyabano Candy – mature but firm fruits peeled sliced to about 1 cm thick with a stainless steel knife, and soaked at once in water to avoid discoloration. It is cooked in syrup (2 parts sugar to 1 part water) for 10 minutes and soaked in syrup for 1 week, boiling it daily for 5 minutes. It is cooked over a slow fire until syrup becomes sugary. It is removed from fire, separated from sugar, cooled and wrapped individually in cellophane.
Guyabano Jam – the fully ripe, sound fruit is peeled and its seeds are removed. To every cup of fruit, an equal amount of sugar is added and the mixture is cooked to jam consistency. It is poured while hot in a preserving jar. After removing the bubbles, the jar is half-sealed, sterilized for 25 minutes in boiling water and sealed completely.
Frozen Guyabano Pulp – the sound ripe fruit is peeled and its seeds are removed. To every cup of fruits are added ¼ cup refined sugar and 2 tbsp. calamansi juice. The mixture is packed in a plastic bag container and stored in a freezer (240F). To serve as juice, enough cold water and sugar are added to taste.
Guyabano Jelly – thoroughly ripe fruit is rinsed and sliced, retaining the skin and seeds. It is put in a pan with enough water to cover, and boiled until soft, with constant stirring. It is removed from the fire and passed through a double cheesecloth. The extract is returned to the fire, boiled until all the scrum has risen, and strained again. To each cup, 1 tbsp. calamansi juice is added and the mixture is boiled again. To the boiling juice is added 1 cup hot dissolved sugar and the mixture is boiled until it hardens on spoon removing all rising scrum in the process.
Guyabano Juice Concentrate – fully ripe, sound fruits are thoroughly washed with detergent and carefully rinsed in water. They are cut into halves and the skin and seeds are removed. Two cups of water are added to 1 pulp, the mixture is blended to facilitate juice extraction, and strained through a muslin cloth bag. The clear juice is concentrated juice is “cut back” to 160C Brix by adding freshly prepared juice. Ascorbic acid equivalent to 50 mg/cc is added during pasteurization to retard normal oxidation browning in storage. Fortified concentrate is pasteurized at 850C for 5 minutes, hot filled into previously sterilized cans, sealed completely and processed into boiling water for 10 minutes. Cans are immediately cooled in running water and wiped dry.
BROWN, W. H. 1951. Useful Plants of the Philippines. Bureau of Printing Press, Manila. Volume 1. pp. 541-543.
BUREAU OF AGRICULTURAL STATISTICS, DA. 2003. Crop Statistics.
CORONEL, R. E. 1983. Promising Fruits of the Philippines. UPLB. Pp. 235-246.
CULTURAL DIRECTIONS FOR PHILIPPINE AGRICULTURAL CROPS. 1972. BPI. Vol. I, Fruits. Pp. 135-136.
SAMSON, J. A. 1980, tropical Fruits (Tropical Agricultural Series). Pp. 216-218.
TECHNOLOGY FOR GUAYABANO PRODUCTION. 1985 (Mimeographed Handouts). Research Division, BPI, Manila.