Jamun Black Plum
The jamun is an important indigenous minor fruit of commercial value. It is also known as black plum, Indian black cherry, Ram jamun etc. in different parts of India. The tree is tall and handsome, evergreen, generally grown for shade and windbreak on roads and avenues.
Jamun are berries with an oblong shape similar to Kalamata olives. They have a dark purple to almost black skin with a starkly contrasting pink or white flesh. The flesh is extremely juicy and has a flavor that combines sweet and tart with a slightly astringent aftertaste. The fruit contains a hard seed which should be discarded. When eaten, the dark-colored skin leaves a stain on the lips and mouth that can last for several hours.
The original home of jamun is India or the East Indies. It is also found in Thailand, Philippines, Madagascar and some other countries. The jamun has successfully been introduced into many other subtropical regions including Florida, California, Algeria, Israel, etc.
Jamun fruit are native to India and surrounding countries: Nepal, Pakistan and Sri Lanka. The tree was introduced to the US via Florida in 1911. Jamun fruit does not ripen off the tree and individual berries ripen at different times; fruit is picked daily and is most often foraged. Jamun can be found a farmer’s markets in India and in the surrounding region.
In India, the maximum number of jamun trees are found scattered throughout the tropical and subtropical regions. It also occurs in the lower range of the Himalayas up to an elevation of 1,300 meters and in the Kumaon hills up to 1,600 meters. It is widely grown in the larger parts of India from the Indo-Gangetic plains in the North to Tamil Nadu in the South. The data about its total acreage in India are not available.
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.
Propagation of jarnun is economical and convenient. Budding is practiced on one year old seedling stocks, having 10 to 14 mm thickness. The best time for budding is July to August in low rainfall areas. In the areas where rains start easily and are heavy, budding operations are attempted early in May-June. Shield, patch and forkert methods of budding have proved very successful. The possibility of better success has been reported in forkert method compared to shield or 'T' budding.
Jamun can also be propagated by inarching but it is not adopted commercially. In this method one year old seedlings raised in pots are inarched with mother jamun trees with the help of wooden stands during June-July.
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.
Planting
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.
Another common way of growing jamun trees is to plant them as shade trees near the farm dwellings and wells. Here they provide a welcome shadow besides fruit.
In early stages, the jamun tree requires frequent irrigations but af1cr the trees gets established, the interval between irrigations can be greatly decreased. Young trees require 8 to 10 irrigations in a year. The mature trees require only about half the number, which should be applied during May and June when the fruit is ripening. During autumn and winter months, just an occasional irrigation may be applied when the soil is dry. This will also save the trees from the ill effects of frost in winter.
Flowering and Fruiting
Flowers are borne in the axils of leaves on branchlets. In North Indian conditions, flowering starts in the first week of March and continues up to the end of April. The pollen fertility is higher in the beginning of the season. The maximum receptivity of stigma is one day after anthesis.
The jamun is a cross-pollinated and the pollination is done by honey bees, houseflies and wind. The maximum fruit set can be obtained by hand pollination when it is done after one day of anthesis. Thereafter, a sharp decline is observed in fruit set.
There is heavy drop of flowers and fruits within 3 to 4 weeks after blooming. Later natural fruit drop can be reduced with two sprays of GA3 60 ppm, one at full bloom and another 15 days after initial setting of fruits.
The pattern of growth and fruit development of jamun can be divided into three phases: the first phase from 15-52 days after fruit set having slow growth of fruit, the second phase from 52 to 58 days after fruit set having fast growth and the third and last phase from 58 to 60 days after fruit set having slow growth and very little addition in fruit weight.
Storage and Marketing
The fruits are highly perishable in nature. They cannot be stored for more than 3 to 4 days under ordinary conditions. However, pre cooled fruits packed in polythene bags can be stored well up to three weeks at low temperatures of 8 to 10°C and 85 to 90% relative humidity.
The fruit is packed and sent to the market almost daily. For marketing, well ripe and healthy fruits are selected. Damaged, diseased and unripe fruits are discarded. These selected fruits are then carefully packed in wooden baskets and sent to the local markets.