The Small seed plot and Select-the-best Technologies | Crop Management (Crop Varieties)

Despite of the increasing demand for potato and the great interest that farmers have in potato farming, the crop’s productivity has been declining owing to insufficient quantities of healthy, high-yielding seed of desirable potato varieties. It is recognized that potato-planting materials contribute about 40% of potato production input costs. Unfortunately, more than 95% of seed potato is sourced from farmers’ own harvests or marke Read more..

Description of the technology or innovation

Despite of the increasing demand for potato and the great interest that farmers have in potato farming, the crop’s productivity has been declining owing to insufficient quantities of healthy, high-yielding seed of desirable potato varieties. It is recognized that potato-planting materials contribute about 40% of potato production input costs. Unfortunately, more than 95% of seed potato is sourced from farmers’ own harvests or markets or neighbours. Such tubers are often of poor health status owing to latent infections by Ralstonia solanacearum (the bacterial wilt causal agent), viruses and other tuber-borne pathogens. Main constraints to seed access include high transaction costs with (43.5%), limited seed availability (40.5%) and limited information on the source of seed (14.0 %). Therefore, increasing the availability of high quality seed potato to farmers, coupled with enhanced management of tuber-borne diseases to reduce quality deterioration, would be a major step towards increasing potato yields and making the potato value chain more competitive.

The seed-plot technique utilizes the principle of maximising tuber production per unit area of limited, disease-free land through high-density planting in seed plots (synonymous with a ‘nursery’). This is achieved by planting well-sprouted seed potato tubers on selected disease-free land on plots measuring 1.8 m wide and a length of not less than 9 m at a spacing of 30cm by 30cm and nurturing the plants up to maturity to obtain seed for the following season as opposed to obtaining seed from ware potato fields where plants are spaced more widely (70 x 30cm in Uganda; 75 x 30cm in Kenya; 80x 30 cm in Burundi). The plots are deeply dug to loosen the soil and then raised to about 15 cm high. Carefully selected tubers obtained from seed plots can then be planted at the usual spacing for ware potato production while at the same time reserving some for the establishment of more seed plots. Field activities include weeding, hilling-up with soil obtained from estimated free from bacterial wilt pathogen land, pesticide application to control pests and diseases as appropriate, dehaulming at plant senescence, harvesting 2-3 weeks after dehaulming, sorting to remove damaged and diseased ones, grading for size separation).

The positive seed selection technique has the principle of selecting the best plants in a ware field (planted at the usual spacing) as mother plants to provide seed for the following season coupled with the removal and disposal of diseased plants as soon as they are seen. The process of selecting seed potato under this technology starts with the identification and marking of healthy-looking potato plants (using pegs) when the first flowers appear on the crop followed by checking the health status of the pegged plants two weeks later in order to removing pegs from the plants that exhibit disease symptoms; the plants that ultimately remain pegged are subsequently harvested individually, ensuring that plants with few tubers or those with malformed tubers are disregarded. The positively selected plants are harvested before the rest of the plants in the field and the seed kept separately for the subsequent season’s demonstration and use. Tubers obtained from all the other plants that are not positively selected in the target field are only used for home consumption or for sale as ware produce.



Assessment/reflection on utilization, dissemination & scaling out or up approaches used

The  Potato  Nursery/  small  seed  plot  and  Select-the-best  Technologies  were  demonstrated  across benchmark sites in Burundi, Rwanda, Uganda and Kenya. The dissemination approach used to promote the  technology  was  use  of  demonstrations  as  training  sites  for  farmers  from  within  and  around  the community  through  innovation  platforms.  The  innovation  platform  approach  and  benchmark  site demonstrations can be used to effectively disseminate these technologies. For successful promotion and adoption of this technology farmers need to be sensitized about potato farming as a commercial enterprise. There  is  need  for  cooperation  between  the  policy  makers,  NGOs,  field  extension  workers,  and  local leaders  in  the  promotion  of  the  technology.  Future  scaling  up  of  the  technology  is  required  in  order to achieve wider impact. 

Current situation and future scaling up

The infrastructural support for production of potato mini-tubers is now available in Uganda, Kenya and Rwanda.  Private  sector  companies  in  Kenya  and  Uganda  have  taken  up  early  generation  potato  seed production  as  a  business  and  find  a  ready  market.  The  Uganda  National  Seed  Potato  Producers Association among other farmer groups have also sprouted to produce seed for sale. 

Economic Considerations

The gross margins comparisons are as follows (in Kenya Shs)

Table 6: Comparison of Gross margins before and after the Project

Inputs/Output Before the Project After  the Project
50kgs bags 10 @ 1000 =10,000 10 @ 2500 = 25,000
Ploughing By oxen 1,800 By tractor 3000
Harrowing - 1,500
Fertilizer 50kgs bags 2 bags @ 3500=7000 4 bags @ 2500* = 10,000
Ridging  labour 1,500 1,500
Planting labour 4x 200=800ksh 8x200=1,600
Top dressing labour 8x200=1,600  
Fungicide 4,800 (curative) 8,000 (preventive)
Pesticides insecticides) - 8,000
Spraying labour 2,400 4,800
Earthing up 1200 3,600
Harvesting 5000 10,000
Yield 50 bags 99 bags
Prices per 110-kg bag 2,000 Ware =2,800 & Seed 3,000
Income 100,000 285,600
Total cost of inputs (KShs) 36,100 77,000
Profit (Kshs) 63,900 (US$ 752) 208,600 (US$ 2,454)

Gender considerations

The seed plot technique particularly has been embraced by women and youth. Indeed the majority of seed potato  producers  who  have  adopted  the  seed  plot  technology  are  women.  This  is  because  the  land requirement for the seed plot is small and hence women and youth with limited access to land can employ the technology. The labour requirement is also minimal.

Case study or profiles of success stories

Florence Kinoti (a farmer in Meru County, Kenya)
I am a potato farmer from Kenya. My farm is on the leeward side of Mt. Kenya and it is in Timau Ward, Kirimara Location, Buuri Sub-County, Meru County. Potato growing is the main source of income in the area. Many farmers in our area experience low productivity due to lack of quality seed potato. This makes the  farmers  recycle  seed  potato  from  their  own  farm  stores,  which  in  most  cases  have  tuber-borne diseases, e.g. bacterial wilt. Although the situation is still not at its best for majority of the farmers  in the
area, there has been a great improvement for some of the farms through the intervention of an ASARECA seed potato project introduced to us by National Potato Council  of Kenya (NPCK) and Kenya Agricultural Research Institute (KARI) in collaboration with the Ministry of Agriculture. Through the area agricultural extension office, the combined team of project implementers (NPCK and KARI) identified farmer groups for implementation of the project. The implementers  informed farmers and agricultural extension officers
and  other  stakeholders  that  the  project  was  supported  by  ASARECA.  The  team  from  Staple  Crops  at ASARECA  participated  with  us  in  all  the  stages  of  the  project  implementation.  They  introduced technologies  for  improving  the  availability  of  quality  seed  potato,  which  were  readily  accepted  by  the participating  farmers.  These  were:  Seed-plot  technique  and  Positive  seed  selection.  In  our  area,  six  (6) farmer groups were identified. Each group was asked to select four (4) members to act as the lead persons in the implementation of the project activities; 2 members were trained as TOTs, 1 member was trained for hosting the seed-plot technique demonstration and 1 member was trained for hosting the positive seed selection demonstration. The TOTs and hosts of technol ogy demonstrations were trained on the various aspects  of  seed  potato  production  and  handling.  After  that the  group  members  went  to  do the  same  on their  plots  (baby  plots).  After  the  training,  practical   demonstration  were  done  on  how  the  technologies work. Thereafter, group members were encouraged to do the same on their own farms with the guidance of the TOTs and supervision of the project team. The community around got very much attracted by the very  good  growth  of  our  potato  crop,  especially  in  seed  plot,  and  wanted  to  now  more  about  the technology.  Through  the  demonstrations,  the  community  has  realized  the  importance  of  quality  seed potato hence improving the productivity resulting to increased income. The 6 groups came together and formed  an  association  nown  as  Kirimara  Potato  growers’  Welfare  Association.  Kirimara  is  the  native name  for  Mt.  Kenya.  So  far,  6  members  of  the  association  want  to  be  seed  merchants  and  they  have already started being trained to start certified seed in collaboration with KARI and KEPHIS. Through the use of higher quality seed potato, production in the area has increased and also created employment to our community  members.  Many  farmers  now  can  acquire  clean  seeds  from  their  already  existing  farms through positive seed selection hence this seed is multiplied in a seed plot by the small-scale holders. The
ASARECA-support project came to our rescue when we did not know how to improve the availability of quality seed potatoes. The design of the project motivated farmers because they initially bought seed and after  harvesting  and  selling  the  seed,  NPCK  and  KARI  rewarded  the  farmers  by  refunding  the  money. This has increased farmers income even more for further investment in seed production. Kirimara Potato Growers’  Welfare  Association  plans  to  become  even  bigger,  have  more  members  and  increase  our incomes.

Application guidelines for the users

The quantity of seed potato obtained from seed plots is dependent on factors such as variety planted, postplanting management practices and presence, absence or level of bacterial wilt disease in seed plots. For an  average  seedplot  planted  with  480  tubers  (about  80  rows of  6  tubers  each  at  a  spacing  of  30cm  by 30cm), farmers obtained enough seed to plant 6 to 7 such seedplots to multiply seed during the following season. This means that a farmer can achieve a lot of seed for his/her own farm and even sell surplus seed by starting with a small quantity (1 or 2 bags of 50kg) of certified seed.

Contact details

Bararyenya Astère,
Institut des Sciences Agronomiques du Burundi (ISABU)
P.O Box : 795 Bujumbura-Burundi
Tel: +25722264170/+257225798

Nahayo P Claver,
Confédération des Associations de Producteurs Agricoles pour le Développement (CAPAD)
P.O Box 24. Bujumbura-Burundi
Tel : +257 22227902/+257 22273691/+25779967257/ +257 79 985 926

Wachira Kaguongo  
National Potato Council of Kenya NARL-KARI Campus, Waiyaki Way  
P.O. Box 29982-00100, Nairobi, Kenya
Tel. +254722597389/ +254725673745/ +254 20 2338231

Zachary M Kinyua
Kenya Agricultural Research Institute (KARI) National Agricultural Research Laboratories, Kabete
(NARL Kabete).  
P. O. Box 14733-00800, Nairobi, Kenya
Tel: +254 (0)20 4444144.  
Cell phone: +254 733 999444 Email:

Oggema Natabona Judith
Agricultural Development Corporation (ADC) - Seed Potato Complex – Molo  
P. O. Box 47101-00100 Nairobi, Kenya.  
Tel: +254 020-2250695,  
Cell phone: +254 721 202565  

Tindimubona Stephen,
Uganda National Seed Potato Producers Association (UNSPPA)  
ASARECA TIMPS-Revised Nov 2014  Page 45
P.O. Box 329, Kabale, Uganda,  
Mobile : +256(0)772657621 and 751657621

Namugga Prossy,
Kachwekano Zonal Agricultural Research and Development Institute (KAZARDI)  
P.O. Box 421, Kabale, Uganda  
Tel: +256 (0) 486426496 (office)
Mobile : +256 (0)782361597  
Fax: +256 (0) 486426496

Additional information

The mother and baby plot concept was adopted by farmer groups. Farmers learnt from the demonstration plot (mother) and replicated the same in their own farms (baby). Prior to the establishment of seed plots a training  of  TOTs,  Positive  selection  and  mother  plots  hosts  were  trained. The mother plot gardens per group were established using certified potato seeds. The baby plots established used both certified seed bought by individual farmers and that supplied by ASARECAS. Some farmers were unable to establish own positive selection plots due to limited land space whose rotation regime did not allow them to grow potato on wide scale.

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