Farmers have already demonstrated that India's agro-climatic conditions can be improved to allow for the growing of Rambutan, one of Southeast Asia's most popular fruits. Rambutan cultivation is appropriate in Kerala, Tamil Nadu, Mangalore, Kudak regions of Karnataka, and Maharashtra's Konkan region. In our garden, we can grow rambutan as a decorative tree.
The juicy and delicious inner section of the seed is appetising. Carbohydrates, vitamins, calcium, magnesium, and potassium are abundant in fruits. The antioxidants found in the rind and aril of the rambutan have been shown in studies to inhibit the growth of cancer cells.
Favourable climate & soil
Rambutan flourishes in warm, tropical regions. The presence of higher humidity and a favourable climate are crucial considerations. A minimum of 150 cm of well-distributed yearly rainfall is also required. The trees thrive at altitudes of up to 800 feet above sea level.
Temperatures between 22 and 35 degrees Celsius are excellent for optimal growth. The tiny climatic fluctuations, on the other hand, would have little effect on its yield and growth. The best soils for optimum growth and yield are well-drained loamy soils with high organic content. The soil's acidic and alkaline characteristics should be kept in check (pH value 4.5 to 6.5).
Popular Varieties
Rambutan cultivars are offered in a wide range of commercial and farmstead varieties. N18, HG Malwana, HG School Boy, HG Baling, HG Rongrien, and HG Jarum Emas are commercial types, whereas E35 and King are homestead varieties.
The N18 and E35 kinds were developed by Homegrown Biotech in Kottayam. Furthermore, in Kerala, Homegrown discovered and produced a variety of commercial and homestead rambutan varieties that are popular in Thailand, Sri Lanka, and Malaysia.
Propagation
The scientific name for the Rambutan, which belongs to the Sapindaceae family, is Nephelium leppaceum. The word "rambutan" comes from the Malay word "rambut," which means "hair." The shape of the fruit is round or oval. A cluster typically comprises five to twenty fruits. The red or yellow colour of the leathery outer shell is common.
Seedling propagations are not used in rambutan culture because of the difference in sex type of flowers. Instead, budding is the right method of producing high-quality plants. If nurtured well, it starts flowering after three years and yields optimum production after six to eight years.
1. The ideal spacing between two saplings is 40 ft, which can vary from place to place depending upon the weather condition.
2. In one acre of land, up to 35 saplings could be planted.
3. The pits (1m sq.) should be filled with topsoil mixed with 3 pots of well decomposed cow-dung manure or compost and 1 kg each of rock phosphate. Then place the plant with the bud union above the soil level.
4. A handful of compost or dried cow-dung manure and rock phosphate mixed with soil should be sprinkled around the planting hole. Additional fertilizers can be given after 6 months, but only after the new flush of leaves are emerged and matured.
5. Proper irrigation is essential during the dry season. Keep the orchard clean by periodic removal of weeds. Dried branches and water suckers should be removed regularly.
Since rambutan tends to have long, upright growth, early pruning is recommended. When the budding attains 4 ft, trim the main stem at 2.5 ft. When new sprouts emerge, allow 3 or 4 limbs in different directions, and these limbs produce primary, secondary and tertiary branches, giving the tree a semi-elliptic shape. This will help to attain optimum yield. We can complete this planting method in two years.
Fertilizer Application
Rambutan is a plant favorably responding to fertilizer application. Fertilizers could be given only after the new flush of leaves are emerged and matured. Adding 5 kg of compost or cow dung manure mixed with soil is effective. Mulching is found to be very effective in moisture conservation. Spraying ‘jeevamritham’ could stimulate the growth of useful microorganisms. It will also help the plants to overcome drought. Application of cow dung manure enriching Trichoderma is useful.
3. Fill the pits (1m sq.) with topsoil, 3 pots of fully decomposed cow dung manure or compost, and 1 kilogram of rock phosphate each. Then, with the bud union above the soil level, plant the plant.
4. Sprinkle a handful of compost or dried cow dung manure, as well as rock phosphate mixed with soil, around the planting hole. After 6 months, additional fertilizers can be applied, but only after the new flush of leaves has appeared and matured.
5. During the dry season, proper irrigation is critical. Remove weeds from the orchard on a regular basis to keep it clean. Water suckers and dried branches should be removed on a regular basis.
Pollination
From February to April is the flowering season. According to the age and production of the trees, the right irrigation method is required. Because rambutan is a cross-pollinated crop, honey bees are required for fruit production. The initial stage of fruit production takes three weeks following pollination. After three weeks, we can use new approaches to safeguard its quality once more.
Apply 25 gm Boron (for small trees) and 50 gm Boron (for large trees) mixed with soil at the time of flowering. It is also useful to utilize Pseudomonas fluorescent liquid formulation (6ml/l) in the management of fruit drop and the production of high-quality fruits.
In addition to 200 g of 18 complexes, 100 to 250 g of muriatic of potash and 4-5 g/l of sulphate of potash can be applied as foliar fertilizer to fruiting plants (1lt per tree). Spraying 1g/l wettable sulphur on growing fruits reduces fruit drop dramatically. Fruit drop can be induced by a variety of factors, including a lack of micronutrients and changes in the oxin-cytokinin hormone.
Giving foliar spray by detecting the right proportion of microelements through leaf tissue analysis is effective. Spraying sulphur solution (3g/l) is an effective method for preventing any type of fungus attack.
There are two varieties of blossoms on high-quality trees in orchards. 95 percent of these blooms are functionally female and have a bisexual structure. The pattern of certain bisexual flowers that conduct female activities must be changed to that of males in order to boost output, which accelerates productivity. A 10% cluster of flowers must be located and marked for this operation.
Out of this selected cluster, some buds open at the same time the rest remains as buds. That period is the apt time to spray Superfix solution.
Before 9 a.m., combine one milliliter of Superfix with two liters of water and mix thoroughly. After 6 days, the blooms may have transformed to male flowers and the stamen have broken out; this period allows for increased productivity. In order to produce high-quality fruits, such a critical process must be given the utmost attention.
Pest Control
Usually, pests would not affect well-nurtured rambutan trees. Maintaining 40 ft spacing is a good method of plant protection. Drying up branches, attack of mealybugs, beetles and leaf-eating caterpillars are the major threats to plants. Burning the affected branches is an effective way to avoid further spread. In case of severe attack Neem-based formulations can be used to control leaf-eating caterpillars. Verticillium is effective in managing mealybug infestation.
( Also read: Beneficial Tips On How And When To Plant Fruit Trees)
Dr. Sunny George
Director, Research & Development
Homegrown Biotech
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