Plant Breeding

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Browsing Plant Breeding by Funder "Giz, Wageningen University, IPM Potato Group Ltd."

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    Seed Quality and Variety Preferences Amongst Potato Farmers in North-Western Kenya: Lessons for the Adoption of New Varieties
    (Springer Link, 2023-06-03) Kwambai, Thomas K.; Griffin, Denis; Struik, Paul C.; Stack, Laura; Rono, Selly; Brophy, Caroline; Nyongesa, Moses; Gorman, Monica
    Potato (Solanum tuberosum L.) is an important commercialised food crop in Kenya. Recently, Kenya has realised a huge increase in the number of formally released potato varieties. The performance of these varieties is not clear and their adoption across various growing environments is low. This study explored how availability, access, quality and systems of seed and storability and market demand of potatoes influence farmers’ decisions on choice of varieties they grow and how they select seed for planting in the different seasons. Focus group discussions (83 farmers) and a household survey (225 farmers) were conducted in three major potato growing areas (Lelan, Saboti and Kaptama) in north-western Kenya. Results showed that farmers mainly used farm-saved seed and only 4.9% had used certified seed, while 71% indicated that certified seed was not available locally. Almost all farmers ensured they used healthy seed by visually examining the seed tubers while most farmers also examined the health of the crop in the field before harvest. Farmers renewed their seed depending on the number of cycles used, infection, decline in yield and availability of clean seed. Seed was usually renewed for up to after 5 years of recycling, and generally involved the varieties Shangi, Kabale and Arka. Farmers ranked five variety traits: tuber yield, disease resistance, market demand, early maturity and storability as most important in the choice of a variety. Farmers understood the importance of dormancy and had methods for managing dormancy, but their knowledge was biased to the few varieties they had, particularly Shangi, the predominant variety in the market. Despite agronomic attributes, market demand featured as a primary determinant of variety choice amongst farmers. The findings from this paper can guide use of seed, adoption of new varieties and future breeding of potato varieties for Kenya.
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    Understanding Genotype × Environment Interactions in Potato Production to Guide Variety Adoption and Future Breeding Strategies
    (Springer Link, 2023) Kwambai, Thomas K.; Struik, Paul C.; Gorman, Monica; Nyongesa, Moses; Rop, Wilfred; Kemboi, Edward; Griffin, Denis
    Potato (Solanum tuberosum L.) is a versatile crop given its adaptation, production capacity and utilization, and therefore valuable in many different countries. In Kenya, potato is mainly grown by smallholder farmers for food and cash. Access to quality seed of adapted and acceptable varieties was limited. This led to public–private partnerships with European seed companies working independently or with their Kenyan counterparts in introducing high-quality seed of new varieties. Some of these showed improved yield, quality and disease resistance. However, some European varieties were less adapted to the short photoperiods prevailing in Kenya than the late blight-resistant elite clones from South America, introduced by the International Potato Center (CIP). Traits that influence genotype adaptation can aid breeding cultivars or support their recommendation for certain production areas, but such traits have not been studied in detail for Kenya. This study sought to understand the adaptation of 50 contrasting genotypes from Europe, CIP and Kenya and the traits driving adaptation to four seasons and three altitudes. Genotypes showed a wide range of yields in all environments studied. The factor genotype explained most of the variance for total tuber yield (71.2%), plant height (49.3%) and area under the disease progress curve (25.1%) based on the Wald statistic, followed by season and the genotype by altitude interaction. Other traits studied hardly contributed to the understanding of the responses to the twelve testing environments. However, the largest proportions of variances for days to 50% emergence, days to maturity and canopy cover were accounted for by altitude.