The guava (Psidium guajava Linn.) is one of the most common fruit tree crop in the tropics and subtropics, but found to be indigenous to the American tropics. It has a great potential for extensive commercial production because of its ease of culture, high nutritional value and popularity of processed products. Most common areas where guavas are grown in abundance are: open areas, second-growth forests, backyard or as a part of a mixed orchard. However, at present, there are no existing records for big planting and production of guava in the Philippines.
Medicinal Use of Guava
The bayabas fruit bark and leaves are used as herbal medicine. Its leaves decoction is recognized for its effectiveness to cure several ailments, including the treatment of uterine hemorrhage, swollenness of the legs and other parts of the body, of chronic diarrhea, and gastroenteritis, among others. The most common use of the leaves is for cleaning and disinfecting wounds by rinsing the afflicted area with a decoction of the leaves. In the same way, such leaves are being used to aid in the treatment of dysentery and the inflammation of the kidneys. The bark and leaves can be used as astringent. It can also be used as a wash for uterine and vaginal problems, and is good for ulcers. The medicinal uses of Bayabas appear infinite, as it is also a suggested natural cure for fevers, diabetes, epilepsy, worms, and spasms.
The fruit, aside from being delicious, contains nutritional values with a very high concentration of Vitamin C, which is substantially higher than what is found in citrus. It is also a good source of Vitamin A and other important elements. The fruit contains a large amount of citric, lactic, malic, oxalic and acetic acids and trace amount of formic acid.
The ripe fruit is usually eaten as dessert. It can also be utilized in many ways for making jellies, jam, paste, juice, baby foods, puree, beverage base, syrup, wine and other processed products. It may be eaten sliced with cream and sugar and as ingredient in cakes and pies. It is also used in dishes like “sinigang”.
Some parts of guava tree have medicinal and commercial usefulness. The bark and leaves are used in childbirth to expel the placenta. The leaves can be made into tea and astringent decoction can cure stomachache and act as vermifuge. When crushed or chewed, it is used for toothache treatment; pounded leaves may also be applied locally for rheumatism; can also be used for dyeing and tanning. The bark is sometimes used in complex cosmetics for hystero-epilepsy. Its wood is moderately strong and durable indoor and useful for handle and in carpentry and turnery.
SOIL AND CLIMATIC REQUIREMENT
Soil – guava does well on different soils from open sand to rather compact clay; from strongly acid (pH 4.5) to medium alkaline (pH 8.2) For good fruit production, guava should be grown in rich, deep, well drained soils high in organic matter.
Climate – a rather dry climate is favorable for guava production. It may thrive best in the tropics at elevation from sea level to 5,000 feet with a tropical or near tropical temperature requirements.
Seed germination and care of seedlings
Guava seeds should be thoroughly cleaned soon after extraction from the fruits. It is necessary to treat the seeds with fungicides to prevent damping-off. They should be planted early to ensure high germination. Germinated seeds in beds or boxes with a medium of fine sand or an equal mixture of sand and topsoil. Sow them evenly in the furrows 2-3 cm apart and lightly cover with soil 0.5 – 1.0 cm deep. Water regularly to keep the soil moist.
Protect the seedlings against insect pests and diseases by spraying insecticides and/or fungicides. A month after emergence or when the first true leaves have formed transplant them in individual containers, like polybags using medium clay loam soil mixed with compost. Partial shading is necessary until the plant has recovered its growth. The plant is ready for planting or as rootstocks after one year
Propagation – guava is usually propagated by seeds. It can be propagated asexually through root suckers, root cutting, grafting, marcotting, budding, grafting and inarching.
Seed Propagation – propagation of guava is nearly always by seeds. Guavas are open-pollinated producing seedlings, which are highly variable in character. Variability in seedlings can be minimized by hand –self-pollination or individual flowers.
Root suckers and root cuttings – the use of root suckers is probably the oldest method of asexually propagating guava. Root suckers are induced by severing roots to a few feet from the base of the plants and these are transferred when roots and shoots are established.
Root cutting is done by cutting about 12-20 cm long parts of any butt very small or very large roots. These can be induced to sprout and form new plants provided it is placed in a suitable medium in a well-drained propagating bed. Both the use of root suckers and root cuttings are relatively slow methods of propagating guava.
Budding – an efficient vegetative propagation is by budding selected variety on seedling rootstock. Both the patch bud and forkert techniques are recommended onto seedling rootstock. The diameter of seedling stock and budwood should be from 15-25 mm. Budwood should be mature, bark no longer green. Condition the budwood by cutting off the leaves of selected branches 10-14 days before removing the branches for budwood. During this period the buds become more enlarged and grow more readily after budding.
Air layering – for this method, low branches of guava are bent down, about 12 – 15 cm of the branch is covered with soil and kept damp to induce root formation.
Stem cuttings – propagation by stem cuttings is made from the young wood at the end of the branches. These are rooted in sandy loam soil in propagating bed in a nursery house or shed. Guava stem cuttings treated with Indole Butyric Acid (IBA) or Napthalene Acetic Acid (NAA) proved to be successful for rooting and produce numerous and vigorous roots.
Plow the area once or two times followed by several harrowings to completely pulverize and expose the soil. It is best done during the dry season.
Stake the field and dig holes at a distance of 5 – 7 meters to accommodate 277 seedlings in a hectare. In fertile soils, wider spacing is desirable.
Planting – the planting materials are transplanted into the holes earlier prepared after pruning some of the leaves and removing the plants from the containers. The plants are aligned with other trees in all directions. The best time to plant is at the onset or during the rainy season.
Weeding/cultivation – shallow cultivation around the base of the plant is recommended to prevent root injury, incorporate organic matter into the soil and to control weeds especially when trees need all the available soil moisture.
Pruning – pruning is a must in guava production. This is done if a certain form is desired like growing the tree with a spreading or symmetrical or limited crown or to keep number of branches. However, when the trees have established a strong framework and started to bear fruit, little training is required. The root sprouts; low-lying branches, disease infected and other dead branches, which are unnecessary just, have to be eliminated.
Fertilization – guava trees should be kept healthy through application of fertilizers from the time they are planted until they continue to produce fruits.
In the absence of definite information regarding the fertilizer requirements of guava in the Philippines, it is about 100-500 g ammonium sulfate will be applied around the base of each tree twice a year. The fertilizer will be applied one month after planting and 6 months after or towards the end of the rainy season. The amount will be increased, as the tree grows bigger. At the start of fruiting, each tree should be given about 300 – 500 g complete fertilizer, preferably one containing more nitrogen and potassium per application. At the peak of production (about 10 –18 years, an annual application of 2 kg or more complete fertilizer per tree, split in application may be required to sustain growth development and production of fruits.
Irrigation – no irrigation is required when trees are planted during the rainy season. But in case of prolonged dry weather, the orchard should be irrigated every 10 days or as often as maybe necessary. Irrigation when applied during fruit development can increase production through fruit size.
Intercropping – while the guava trees are not yet fully productive, intercropping of short season crops like vegetables, leguminous crops, root crops and other annual crops can be done. Aside from added income it will also prevent the growth of weeds and help cultivate the land in the orchard. However, this intercrop should be removed once the main crop becomes two crowded
PROCESSING AND UTILIZATION
Preparation of Guava Products
Select ripe and sound fruits. Cut into quarters. To 1 part fruits, add 2 parts water. Boil until the fruits are soft. Strain and measure the extract. To every three (3) parts extract, add 1 part sugar. Stir and measure the extract. Cool. To every 15 to 15 liters, add one-tablespoon yeast. Place in demijohns to ferment. This will take from two weeks or longer. When the fermentation is completed, transfer into wine barrels and age for at least one year.
Select equal mixture of green and ripe guavas. Wash and cut into halves or quarters. For every kilo of guavas, add 2 liters of water. Boil in enamel or stainless steel basin for 30 minutes. Strain thru a cheesecloth bag. Crush the pulp and boil again, using 1-½ liters of water. Strain and combine the 2 extracts. Measure. To every cup of the extract, add ¾ cup of sugar and 1 tablespoon of calamansi juice. Boil once to dissolve sugar and strain. Cook over strong fire until the temperature reaches 107o-108o until a soft ball is formed when the jelly is dropped in a cup of water. Pour in sterilized dry glass jars.