Jamun is indigenous to India. Its tree is tall and evergreen. Therefore It is generally grown as avenue tree or as wind break. Though the fruits are liked by all and sell at a high price, but it is still not grown as an orchard tree. Jamun is found all over India. Jamun fruits are a good source of iron and are said to be useful in the troubles of heart and liver. The seeds of Jamun are an effective medicine against diabetes and their powder is widely used in India to control diabetes.
Since Jamun is a hardy fruit, it can be grown under adverse soil and climate conditions. It thrives well under both tropical and subtropical climate. It requires dry weather at the time of flowering and fruit setting. Early rains are beneficial for better growth, development and ripening of fruit. Young plants are susceptible to frost.
The Jamun trees can be grown on a wide range of soils - calcareous, saline sodic soils and marshy areas. Deep loam and well-drained soils are, however, the most ideal. It does not like very heavy and light sandy soils.
The most commonly found variety of Jamun fruit is often oblong and has a deep purple to bluish colour. The pulp of the fruit is grey to pink in colour, and has a seed in the centre. The other variety which one can find is a seedless variety ranging in colour from purple to white Gokak (Dupdal).
The Jamun is propagated both by seed and vegetative methods. Due to existence of polyembryony, it comes true to parent through seed. Though vegetative methods followed in most cases have attained some success, seed propagation is still preferred. However, seed propagation is not advisable as it results in late bearing. The seeds have no dormancy. Fresh seeds can be sown. Germination takes place in about 10 to 15 days. Seedlings are ready for transplanting for the use as rootstock in the following spring (February to March) or monsoon i.e. August to September.
About 60% air layers are obtained with 500 ppm IBA in lanolin paste, provided air layering is done in spring and not in the rainy season. Better rooting through cutting is obtained in Jamun under intermittent mist.
Semi-hardwood cuttings of both S. jambos and S.javanica, 20-25 cm long, taken from the spring flush and planted in July treated with 2000 ppm IBA (Indole Butyric Acid) give better results.
Jamun is an evergreen tree and can be planted both in spring i.e. February -March and the monsoon season i.e. July-August. The latter season is considered better as the trees planted in February- March have to pass through a very hot and dry period in May and June soon after planting and generally suffer from mortalities from the unfavourable weather conditions.
Prior to planting, the field is properly cleared and ploughed. Pits of 1 x 1 x 1 m size are dug at the distance of 10m both ways. Usually, work of digging of pits is completed before the onset of monsoon. The pit are filled with mixture of75% top soil and 25% well rotten farmyard manure or compost.
An annual dose of about 19 kg FYM during the pre-beating period and 75 kg per tree bearing trees is considered. On very rich soils, the trees have a tendency to put on more vegetative growth with the result that fruiting is delayed. When the trees show such a tendency, they should not be supplied with any manure and fertilizer and irrigation should be given sparingly and withheld in September-October and again in February-March. This helps in fruit bud formation, blossoming and in fruit setting.
Grown up trees should be applied 500 kg N, 600gand 300g K /plant /year.
Irrigation should be given just after manuring. Young plants require 6-8 irrigations for better growth. In bearing trees, irrigation should be given from September to October for better fruit bud formation and May to June for better development of fruits. Normally 5-6 irrigations are required.
Flowering starts during March and continues up April in north Indian conditions. Fruits ripen during June - July or with the onset of rains. It takes about 3-5 months to ripen after full bloom. Fruits change their colour from green to deep red or bluish black. This is a non climacteric fruit hence it does not ripen after harvesting. The average yield of fully grown budded and seedling trees are 50-70 kg and 80-100 kg /plant /year.
Source : KVK, Tumkur, Karnataka