#114Grafting in nurseries
114⸱AConcept
- Improves the coffee plant’s resistance to pests and diseases
- Improves the coffee plant’s tolerance to rising temperatures and drought
- Increases the coffee yield
- Improves coffee quality
Grafting is a vegetative propagation technique that joins plant parts from different plants in a way that they keep growing together as one plant. The objective is to combine the desirable characteristics of each plant in the newly created plant.
The rootstock forms the base of a grafted plant. It is typically chosen for its robustness, broad adaptability, and ability to withstand various biotic and abiotic stresses, including unfavorable soil conditions, pests or diseases, drought, or climatic shifts.
The scion is a shoot or bud that is grafted onto the rootstock. It stems from a healthy plant that is chosen for its high yield or superior quality.
This practice allows farmers to enhance poor-quality plants and cultivate a more desirable or superior species or variety; examples are the grafting of Arabica on Robusta or Arabica on Liberica or combining different Arabica varieties.
Grafting was originally used to control nematodes, a coffee root pest. Robusta is a coffee species that is resistant or tolerant to nematodes. Therefore, it can serve as a rootstock in case of nematode infestations on the coffee plot.
But also without nematode infestations, Robusta provides useful rootstock as its root growth is more extensive and vigorous than that of other coffee species. This allows for better resilience to effects of climate change, such as poor rainfalls, prolonged droughts, and high temperatures, as well as poor or heavy soils.
114⸱BTo be considered
The grafting should be done by a grafting expert. The more experience and expertise the person has, the better the results.
It is recommended to use high-quality rootstock and scion to increase the chances of a successful graft.
It should be considered that grafts with Robusta as a rootstock might have development limitations in cold zones of higher altitudes, above 1,200 meters above sea level. This is because Robusta coffee is native to warm and humid lowland areas of Africa, so the development of a plant grafted on could not have a satisfactory growth and productivity in higher altitude areas.
Grafting can provide an opportunity to involve young people and women in the professionalization of this work and their participation in the coffee chain.
Timing: A successful graft at the nursery usually can be concluded after 45-50 days/1-2 months from the graft to the full callus development.
The grafting should be aligned with the nursery production to ensure that the grafted plants are ready when renovation or new planting occurs.
114⸱CImplementation
Materials
It is highly recommended that a grafting expert performs the grafting procedure.
Rootstock with the following features:
- E.g. Robusta, Arabica or Liberica, depending on region
- Compatibility with the scion. Information about that can often be obtained from national coffee research institutes or local non-government organizations.
- Robust roots.
- Resistant to pests or diseases.
- A sturdy stem.
- A diameter equal or larger than that of the scion, at least the size of a standard pencil.
Scion with the following features:
- E.g. Arabica or Robusta
- Compatibility with the rootstock. Information about that can often be obtained from national coffee research institutes or local non-government organizations.
- Desirable traits such as high yield or quality.
- Healthy and free from pests.
- Orthotropic, vertically growing.
- Straight shape.
- A diameter equal to or smaller than that of the rootstock, with a maximum of 1 cm.
114⸱1Preparation
Generation of rootstock and scion as seedlings:
114⸱2Procedure
The grafting is ideally done in the morning hours when there are still rather moist conditions.
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Prepare the rootstock:
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Prepare the scion:
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Connect the scion and the rootstock:
Parafilm tape provides a solid tie, avoiding the entry of water that can favor the development of fungi, and it increases the number of grafts accomplished per person if working with several grafters.
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Propagators provide the optimal conditions for the early growth and development of the newly grafted plants before they are transplanted to nurseries or fields. They are recommended in areas where the grafting phase coincides with very dry and hot, or very cold, climatic periods.
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If the scion dies and doesn’t show any growth and shoots, the grafting procedure has failed and should be repeated.
114⸱DEconomic benefits
Higher coffee yield
The effects of this tool can lead to a higher coffee yield and therefore a higher income.
Lower pesticide costs
This tool reduces the demand for chemical pesticides and therefore saves input costs over time.
Lower renovation costs
This tool increases the lifespan of the coffee trees. They need to be renovated less frequently which reduces the long-term production costs.
114⸱EGreen benefits
Less pesticides needed
This tool reduces the need for chemical pesticides. This reduces water pollution, protects the ecosystem, improves soil life, and saves resources.