Both a food security crop and cash crop, potato is a source of income for farmers, traders and sellers. In Kenya alone, potato creates employment along the value chain for 2.5 million people, and the value chain is worth an estimated $480 million annually.

Yet farm incomes in Kenya and other African countries are hindered by low yields: 8-15 tonnes per hectare, about half of what smallholder farmers could achieve with better inputs and practices. Limited access to clean planting material is a major barrier to increasing productivity.

Most potato farmers in Africa plant poor quality seed they save from the previous harvest or purchase on unregulated local markets. Often infected with disease, this seed potato performs poorly. Expanding farmer access to quality seed of improved potato varieties is essential to boosting yields and earnings.

The cuttings technology was introduced into Kenya to ramp up production of high quality seed by the International Potato Center (CIP) through the Feed the Future Kenya Accelerated Value Chain Development Program of the United States Agency for International Development (USAID), with subsequent support by the CGIAR Research Program on Roots, Tubers and Bananas. Important partners of the program are Farm Input Promotions Africa, and the county governments of Kiambu, Nakuru, Uasin Gishu and Meru. Known as rooted apical cuttings, the technology was developed years ago by scientists from the Vietnamese Research Center for Experimental Biology and CIP, and has greatly improved potato yields and revitalized the value chain in southern Vietnam. The use of apical cuttings is now starting to address seed gaps and drive business opportunities in the East African nation.

Scaling up seed production

Seed potato multiplication rates are low compared to other crops — approximately 10 seed tubers per plant, compared to as much as 200 for grains. This leads to shortages of quality seed, forcing farmers to plant substandard tubers, which seriously hinders harvests.

Critical to seed production is starter material used for onward multiplication in the field. Over the past decade, CIP has promoted technologies to produce minitubers, which serve as starter material for growing high-quality seed potato, which has contributed to a ten-fold increase in the supply of quality seed in Africa.

Rooted apical cuttings (RAC) are an alternative to minitubers accelerating seed production. There are two stages in RAC systems: production of cuttings in a screenhouse, then a change of hands to a seed producer or farmer to plant RACs in the field to produce high numbers of seed tubers. Apical cuttings are produced from in vitro plantlets by rooting new shoots which are then transplanted in the field where each cutting produces 10-20 or more tubers. One tissue culture plantlet can produce over 100 cuttings and, in turn, 1,000-2,000 first-generation tubers that serve as starter material for successive generations of field multiplication as compared to traditional systems whereby one tissue culture plantlet produces 10-50 minitubers (first-generation tubers), depending on the production system. Apical cuttings can be combined into minituber production systems to further boost production by first making cuttings, then producing minitubers, thereby maximizing the productivity of each tissue culture plant.

High productivity at the first stage of seed production means that commercial seed can be sold after two seasons of multiplication, while still being economical. With high quality seed being available for farmers after a few field generations of multiplication, seed produced from apical cuttings can be saved on-farm for a further few seasons without significant risk of quality loss, provided that good agricultural practices are followed. Apical cuttings offer opportunities for seed production in areas with insufficient land for traditional seed bulking and crop rotation and accelerate disseminating novel varieties. Farmers can also plant apical cuttings in nursery beds to produce seed on-farm.

Introduced to farmers in Kenya just five years ago, this technology has already been included in the national potato certification protocol. Private companies produce and sell apical cuttings to seed businesses to produce certified seed, and to farmers and farmer groups to produce their own seed. Large- and small-scale nurseries sold 390,000 and 586,000 cuttings in Kenya in 2019 and 2020, respectively. In just two planting cycles (one year), these cuttings can generate approximately 2,400 and 3,600 tonnes of high-quality seed potato, sufficient to plant 1,200 and 1,800 hectares worth $1.3 and $2 million, respectively.

A growing number of small-scale seed "multipliers" and smallholder potato farmers have begun purchasing cuttings to produce seed. One of them, Cecinta Nduru, used to grow potatoes for the local market but now earns much more as a seed producer. With CIP training, she began producing apical cuttings from tissue plantlets in her small nursery.

"This technology gives very high returns for farmers who buy cuttings, in terms of seed quantity and quality," Nduru said.

Apical cuttings have the potential to greatly expand the supply of seed potato. This appropriate technology is poised to contribute significantly to improving access to seed and the accompanying increases in yields and incomes of smallholder farmers in Kenya, and beyond.