Superior kale varieties boost harvests, fight diseases

Sukuma wiki farmers in various areas of the country are recording a harvest boom thanks to new five improved lines that are positioning farmers to new markets for a crop grown by 90 percent farmers and consumed at least thrice a week by almost every Kenyan household.

Majority of the farmers who grow sukuma wiki retain their seed from local varieties from year to year. However, this traditional process carries risk of spreading seed-borne diseases, particularly black rot (bacterial) and Alternaria leaf spot (fungal). A good crop cannot be achieved without viable seed, and yet access to commercial varieties is limited. Most varieties are imported and expensive, and quality is still unreliable

Through a collaborative project, a team investigating the problem of poor quality in kale seed discovered that the best kale plants in Kenya originate from Kinale, a forested region on the edge of the Rift Valley. To identify potential varieties, the team worked with kale farmers in Kinale and selected individual plants from the "Kinale" kale landrace.

The chosen plants were then propagated by staff from the Kenya Agricultural Research Institute (KARI) and the CABI regional headquarters in Nairobi to obtain clean, disease-free seed. Five distinct, uniform lines were developed, and sufficient quantities of clean seed produced for supplying a thousand small-scale farmers for evaluation, in all kale growing regions of Kenya. CABI Africa headquarters in Nairobi led the activities in Kenya. Agriculture Extension staff from Lari Division of Kiambu District facilitated activities involving farmers in the division.

"To be frank," says Margaret Ngaithe, one of the farmers involved in the testing,"there is no comparison between the ones I usually plant and the CABI improved ones." Margaret has been harvesting leaves from the same stalks for over a year, so is naturally reluctant to dig up her improved kale plants, which are still out-performing her local varieties.

The improved lines not only flower later, providing a longer period of production, but also produce a better quality leaf. According to Margaret the leaves have better colour and a sweeter flavour, and are so popular with her customers that some have visited her farm to buy more. Her only concern is whether she will be able to access more of the seed which had only been provided for the trials.

Ndirangu Njoroge, a Kinale farmer involved in the original selection trials, has since received training from KARI and CABI. He has been experimenting with the cleaned seed, and has a notebook full of plot numbers, dates and weights to show how each of the five lines has performed. According to CABI field data are as comprehensive and credible as those of a researcher. Looking at Njoroge's top performing line, CABI notes that one or two plants are showing signs of viral infection, but that this is insignificant compared with normal rates of infection, typically around 50 percent or more.

With successful seeds, the CABI scientists have set their sights on a new goal. Dynamic, ambitious, and with the full support of the project partners, they has formed a group with neighbours, to set up commercial seed production. The group has received training, from preparing and maintaining a disease-free plot to safe packaging and storage to ensure a long shelf-life. The Kenya Plant Health Inspection Service (KEPHIS), responsible for seed certification, has also been involved, and the farmers have learned about how seed plots will be inspected, the standards to be met, as well as practical ways of achieving these. Trials conducted to establish the optimum seed production method found that harvesting leaves up to the time of flowering (the "half pick" model) was preferential to "no pick" or "fully pick" models, from which seed harvests were lower.

To become a registered seed merchant in Kenya, however, is both expensive and demanding. The Kinale group has therefore been advised to work with existing seed companies, to generate income by bulking seed on their behalf. One such seed company, Lagrotech, has been working closely with the group, and the relationship has been mutually beneficial. Dr Moses Onim, director of Lagrotech, is excited by what he and his colleagues have learned about genetic diversity in vegetables, through their contact with the Kinale farmers and their kale varieties. He also appreciates that working with the communities has created a new opportunity to commercialise varieties that will find a very ready market.

Already, indications are that improved seed production will provide economic benefits to both seed producers and kale farmers with indirect benefits to consumers. Given time, the partnership could transform kale production in Kenya, and offer strong lessons for other crops in other regions.