GRADE 9 Agriculture PRODUCTION TECHNIQUES – GRAFTING IN PLANTS Notes

GRAFTING IN PLANTS

Topic: PRODUCTION TECHNIQUES — Agriculture (Kenya) — Age: 14

Grafting is a method of joining parts of two plants so they grow as one. It helps farmers and gardeners make trees that give good fruit quickly, resist disease, or suit local soil and climate.

Key words (simple)

• Rootstock — the lower part with roots. Chooses soil tolerance and vigor.
• Scion — the top part (a twig) that has the variety you want (fruit quality).
• Cambium — thin layer under the bark that must meet between scion and rootstock for the graft to grow.

Why graft?

• Get good fruit type quickly (scion gives fruit quality).
• Use rootstock that survives local soil or disease (e.g., drought, nematodes).
• Control tree size (dwarfing) to make harvesting easier.
• Save a damaged tree by grafting a healthy scion onto its rootstock.

Common grafted crops in Kenya

Mango, avocado (Hass), citrus (oranges, lemons), some apples (in highlands), guava and ornamental trees. Farmers graft at nurseries and on farms.

Best time to graft in Kenya

Usually at the start of the rainy season so the graft stays moist — during the long rains (March–May) or short rains (Oct–Dec). For some crops, specific months are used — ask your local extension officer.

Tools and materials

• Sharp grafting knife or clean pruning knife
• Grafting tape / grafting rubber / parafilm
• Grafting wax or sealant
• Pruners, clean cloth, rubbing alcohol to sterilize tools
• Scion wood (healthy, from last season's shoots)

Main methods (simple steps)

1) Cleft grafting (used for larger rootstock, common for mango)

1. Choose a healthy rootstock about 2–4 cm diameter and a scion with 2–3 buds.
2. Cut the rootstock across the top and split the center down about 3–4 cm with a clean knife.
3. Cut the scion into a wedge (two sloping cuts) so it fits the split.
4. Insert the scion wedge into the cleft so cambium layers meet on at least one side.
5. Wrap the graft union tightly with tape and seal with wax to stop water loss.
6. Keep the graft in shade and water the plant; remove any shoots from the rootstock below the graft.

2) Budding (T-budding) — often used for citrus and some fruits

1. Choose young rootstock about pencil-thick and scion bud from last season.
2. Make a T-shaped cut in the rootstock bark and gently lift the bark flaps.
3. Cut a small shield of bark with one bud from the scion and slip it under the bark flaps.
4. Wrap the union, leaving the bud tip slightly exposed.
5. If the bud grows well, cut back the rootstock above the bud later so the bud becomes the new shoot.

Aftercare

• Keep soil moist; avoid water logging.
• Protect grafts from strong sun and wind (use shade net or farm mulch).
• Remove any shoots from the rootstock that grow below the graft.
• Unwrap tape after union is strong (about 6–8 weeks), then remove tape carefully.
• Watch for pests, fungus and disease; keep tools clean to avoid spreading infections.

Good practices and tips

• Always use scions from healthy, disease-free trees.
• Match scion and rootstock size as closely as possible so cambium meets well.
• Sterilise tools with alcohol between cuts — this prevents disease spread.
• Label your grafts with variety and date — useful for farmers and school projects.

Advantages and disadvantages (short)

Advantages: faster fruiting, keep good varieties, disease tolerance, uniform trees.

Disadvantages: needs skill, tools and care; some grafts fail; cost of labour.

Quick checklist before you start

• Scion wood collected and healthy
• Rootstock at right size and good health
• Clean tools, tape and wax ready
• Time of year: start of rains

Short quiz (for students)

1. What is the scion and why do we use it?
2. Why should grafting be done near the rainy season in Kenya?
3. Name two crops commonly grafted in Kenya.

For local advice about which rootstocks and varieties are best in your county, visit your local agricultural extension office or school farm teacher.