Method of Growing and Planting Hybrid Mangosteen Fruit Trees with Rambutan Fruit

Method of Growing and Planting Hybrid Mangosteen Fruit Trees with Rambutan Fruit

The world of tropical fruits is full of surprises, especially when gardeners explore creative methods of combining different species to create unique hybrids. One fascinating idea is the hybridization of mangosteen, often called the “queen of fruits,” with rambutan, a fruit known for its hairy skin and sweet translucent flesh. While natural crossbreeding between mangosteen (Garcinia mangostana) and rambutan (Nephelium lappaceum) is rare because they belong to different botanical families, gardeners have long experimented with grafting, innovative propagation, and soil management to create hybrid trees that combine the strengths of both fruits. This article explores a practical, step-by-step method for growing and planting hybrid mangosteen fruit trees with rambutan fruit, focusing on preparation, grafting techniques, care, and long-term cultivation.

Understanding the Hybrid Concept

Mangosteen grows slowly, often taking 7–10 years to bear fruit. Rambutan, on the other hand, grows faster and produces fruit within 4–5 years. The goal of hybrid planting is not to change the genetic structure instantly but to graft or combine parts of the rambutan with mangosteen to produce a tree that matures quicker, adapts better to different soils, and potentially bears a unique fruit that reflects qualities of both parents. This type of hybrid gardening is popular in Southeast Asia, where both fruits are widely available.

Step 1: Preparing the Seeds and Rootstocks

1. Mangosteen Seeds:
   Choose fresh mangosteen seeds from ripe, healthy fruits. Soak the seeds in clean water for 24 hours to activate germination. Mangosteen seeds must be planted quickly after extraction, as they lose viability if left too long.
2. Rambutan Seeds or Seedlings:
   Rambutan seeds should be cleaned and dried for a few hours before planting. They germinate more easily than mangosteen and serve as excellent rootstocks because of their faster growth rate.
3. Soil Preparation:
   Both species prefer fertile, well-drained soil rich in organic matter. Mix sandy loam with compost and coconut husk fiber to ensure moisture retention. Maintain soil pH between 5.5 and 6.5, which suits both mangosteen and rambutan.

Step 2: Nursery Stage

• Mangosteen seedlings should be nurtured in shaded nurseries for 8–12 months until they reach a height of 30–40 cm. Protect them from direct sunlight and heavy rainfall.
• Rambutan seedlings grow faster and can be ready for grafting in about 6 months. These will serve as the rootstock for the hybrid combination.
• Keep the nursery area moist but not waterlogged, as young mangosteen roots are sensitive to standing water.

Step 3: Grafting Technique

The most effective method of creating a hybrid tree of mangosteen and rambutan is approach grafting or side grafting, as direct seed hybridization is not feasible.

1. Select Healthy Plants:
   Choose a strong rambutan seedling (rootstock) and a healthy young mangosteen plant (scion).
2. Make the Cut:
   On the rambutan stem, cut a 5–7 cm slit. Do the same on the mangosteen stem of similar thickness. Ensure both cuts expose the cambium layers.
3. Join the Stems:
   Press the two cut surfaces together firmly and tie them with grafting tape or biodegradable plastic strips. Seal the area with grafting wax or mud paste to prevent moisture loss.
4. Healing Period:
   Leave the grafted plants in a shaded, humid environment for 4–6 weeks. After successful union, the mangosteen scion will start to receive nutrients from the rambutan rootstock, accelerating growth.
5. Separation:
   Once the graft is firm, cut away the lower portion of the mangosteen seedling below the graft. The rambutan rootstock now supports the mangosteen shoot, forming the hybrid plant.

Step 4: Transplanting to the Field

After 12–18 months in the nursery, the hybrid grafted plant can be transplanted into the field.

1. Planting Holes:
   Dig holes 60 cm wide and 60 cm deep. Fill the base with compost, dried leaves, and a mixture of topsoil.
2. Spacing:
   Maintain a spacing of 8–10 meters between trees, as mangosteen crowns spread widely, and rambutan rootstocks require ample room to develop.
3. Planting:
   Place the grafted plant in the hole, ensuring the graft union is above soil level. Cover with topsoil and press gently to remove air pockets. Mulch with coconut husks or rice straw to conserve moisture.

Step 5: Care and Maintenance

1. Watering:
   Water regularly during the dry season. Hybrid plants, supported by rambutan rootstocks, usually tolerate slight drought better than pure mangosteen.
2. Fertilization:
   Apply organic compost every 3–4 months. Supplement with balanced NPK fertilizer (15-15-15) during early growth stages. Increase potassium content as the tree matures to encourage fruiting.
3. Pruning:
   Prune excess branches to allow sunlight penetration and air circulation. Remove shoots growing from the rambutan rootstock below the graft union.
4. Pest and Disease Control:
   Common pests include fruit borers and mealybugs. Use organic neem oil sprays or natural predators like ladybugs to keep infestations low.

Step 6: Flowering and Fruiting

Hybrid mangosteen-rambutan trees usually take 4–6 years to bear fruit, much faster than traditional mangosteen trees. The fruits may resemble mangosteen in shape but could develop unique skin texture or flavor influenced by the rambutan rootstock. Gardeners often report slightly larger fruits, improved sweetness, and earlier harvests compared to conventional mangosteen trees.

Long-Term Benefits

• Faster Fruiting: Rambutan rootstock reduces the long juvenile period of mangosteen.
• Stronger Roots: The hybrid tree develops resistance to soil variations and pests.
• Unique Fruit Quality: While not a true genetic blend, the fruits exhibit enhanced taste and size.
• Economic Value: Farmers can harvest and sell fruits earlier, making this technique profitable.

Conclusion

The method of growing and planting hybrid mangosteen fruit trees with rambutan fruit is a creative blend of traditional grafting knowledge and modern horticultural innovation. By carefully selecting rootstocks, using approach grafting, and nurturing the plants with proper soil, water, and nutrients, gardeners can enjoy faster growth, stronger trees, and unique fruit harvests. Although this hybridization does not produce a completely new species, it represents a practical way of combining the best qualities of mangosteen and rambutan, ensuring a rewarding experience for fruit lovers and farmers alike.