- The four varieties of macadamia in Kenya are MRG 20, KRG15, EMB1 and KMB 3 which can be grown in Muranga, Kiambu, Kirinyaga, Embu and other parts of the country with similar climates.
- Experts say clean planting material ensure better, healthier plants with increased yields
Image: LOISE MACHARIA
Macadamia has been included on the list of the most lucrative cash crops in Kenya and the most expensive nuts in the world but getting clean seedlings to spur commercial production remains an uphill task.
It is thought Benjamin Franklin could have encountered the macadamia nut literally and learned its propagation process before he came up with the famous phrase “it is a hard nut to crack”.
It begins with a careful selection of seeds followed by soaking the nut for 72 hours to break its seed dormancy.
It is then germinated in an inert medium to avoid diseases. The seed has to be within the nursery for between 15 and 18 months to be ready for transplantation.
Besides breaking the dormancy, soaking the seeds also ensures uniform germination, researchers say.
This writer toured the Kenya Agricultural and Livestock Research Organisation (Kalro) Practical Training Centre in Thika to understand the complexity of propagating this highly rated crop.
The centre was previously known as the Macadamia Research Centre.
It has sand seedbeds where the seeds are sown all the way to tunnels where grafted seedlings are placed before being brought out again.
It is a tedious and long process for researchers before they get clean seeds. But they insist on using clean planting materials in macadamia farming to improve the quality and quantity of the product for better returns.
Anthony Nyaga, a lead researcher at the centre, says the water has to be changed every 24 hours to avoid fermentation and growth of unwanted bacteria or fungi.
“Selecting seeds with highest germination chances involves checking whether the kernel is tight, ensuring they have a light caramel coating and then dipping them in water and getting rid of those that float,” Nyaga said.
Seeds that float during soaking are also removed from the planting stock as this is an indicator of poor formation or rotting.
After soaking for three days, the seeds are then sown on sand seedbeds at a depth of one inch. It has to be placed with its root side down to allow faster germination.
Image: LOISE MACHARIA
“Use of clean planting materials free of disease and pest reduces the bearing period. This means that a normally grown plant might take 10 years to start yielding while grafted ones take roughly three years to start yielding besides other benefits,” Nyaga said.
He said grafting does not interfere with the genetics of the plant contrary to the common belief that grafting is similar to producing GMOs.
With agriculture a major pillar of growth in President Uhuru Kenyatta’s Big Four agenda, Kalro has intensified research and development of various food value chains among them macadamia, mangoes, passion fruits, herbs and spices for export.
This is done in partnerships with other organisations.
“We have to go through this rigorous process to germinate clean rootstock which is later grafted to give farmers highly productive and hardy seedlings for commercial purposes,” Nyaga said.
He said sand is a perfect medium for germinating macadamia because it is inert therefore helping to avoid bacteria and fungi and many other diseases found in the soil.
“Sand is also warmer and dryer compared to soil and therefore supports faster germination which takes place within 21-90 days and is also easy when uprooting the seedlings to replant them in potting bags,” he said.
The researchers place a poly-sheet under the sand beds to avoid complete dryness.
Nyaga said Karlo has developed four hybrid varieties of the plant which first arrived in Kenya in 1945 and does well between 1400m and 2800m above sea level.
The four varieties are MRG 20, KRG15, EMB1 and KMB 3 which can be grown in Muranga, Kiambu, Kirinyaga, Embu and other parts of the country with similar climates.
Once replanted, the seedlings are kept under shade for three months to be ready for grafting
“Mature rootstock should be pencil-thick at the grafting points where scions from a mother block are incised and placed under a tunnel which are more humid and warmer,” Nyaga explained.
The macadamia project is being supported by the European Union-funded Market Access Upgrade Project and will train more nursery owners on grafting. The aim is to reduce the cost of seedlings which currently stands at 400 each.
Nyaga said clean planting materials don't fail nor introduce pests adding that commercial tree nursery owners graft macadamia when it is too young thus results in poor yields.
Good rootstock can withstand weather changes and farmers needed to be assured that it will survive on their farms and guarantee returns.
Through the partnership with Markup which is being implemented by the United Nations Industrial Development Organisation (Unido), Kalro said they will expand knowledge and take certified nurseries near farmers
The project includes formative training of farmers for macadamia management to upscale the take-up of the cash crop and to develop varieties for commercial production.
A food safety and trade expert with Unido Ali Abbas Qazilabash encourages the use of clean planting material saying it ensures better, healthier plants and crops, increased yields and production of quality produce for fruits and nuts.
Abbas said research had suggested hardier plants that are resistant to disease and environmental stress such as drought.
He said the main objective of Markup Kenya is to engage with the scientists from Kalro to help propagate and develop clean planting materials for macadamia.
He said Markup was indexing and cataloging the materials for future use. It will also train county officials, tree nurseries staff to help in further propagation and marketing of materials.
They will also allow farmers to have easy and affordable access to clean planting materials.
Edited by P.O