Improving seed health and seed performance by positive selection in three Kenyan potato varieties.

Abstract

Selecting seed potatoes from healthy-looking mother plants (positive selection) was compared with common Kenyan farmer practice of selection from the harvested bulk of potatoes (farmer selection) in 23 farmer-managed trials. Positive selection assured lower incidences of PLRV (39%), PVY (35%) and PVX (35%). Positive selection outyielded farmer selection irrespective of the agro-ecology, crop management, soil fertility, variety and quality of the starter seed, with an overall average of 30%. Regression analysis showed a relation between lower virus incidence and higher yield for the varieties. The paper discusses the consequences for seed system management in African countries. Furthermore possible additional effects of positive selection are discussed and further research is suggested. The paper concludes that positive selection can benefit all smallholder potato producers who at some stage select seed potatoes from their own fields, and should thus be incorporated routinely in agricultural extension efforts.Resumen Se compararon las selecciones de papa-semilla de plantas donadoras aparentemente sanas (selección positiva) con la práctica común de selección por el productor Keniano del grupo de papas cosechadas a granel (selección del agricultor) en 23 ensayos manejados por los productores. La selección positiva aseguró incidencias mas bajas de PLRV (39%), PVY (35%) y PVX (35%). La selección positiva superó en rendimiento a la selección del agricultor independientemente de la agro-ecología, manejo del cultivo, fertilidad del suelo, variedad, y calidad de la semilla original, con un porcentaje general de 30%. El análisis de regresión demostró una relación entre incidencia viral más baja y rendimiento más alto para las variedades. Este artículo discute las consecuencias del manejo del sistema de semillas en países africanos. Posteriormente se discuten los posibles efectos adicionales de la selección positiva y la sugerencia de más investigación. El artículo concluye que la selección positiva puede beneficiar a todos los productores pequeños de papa que en alguna etapa seleccionen papa-semilla de sus propios campos, y podrían así ser incorporados rutinariamente en los esfuerzos de la extensión agrícola.

A Study of Household Food security and Adoption of Biofortified Crop Varieties in Tanzania: The Case of Orange- Fleshed Sweetpotato

“…The effect on crop income on the adoption of Ejumula is likely to be related to the financial requirements for labor use in the production of sweetpotato. Hired labor is one of the most expensive external inputs in the commercial production of vegetatively propagated crops [29]. Results also show that, among the agroecology variables, farmers in the less dry zone aezP5N10 are more likely adopt Ejumula compared to their counterparts in the drier zone aezP4W3 indicating that agroecology is important in the decision to adopt Ejumula.…”

3. Quality challenges and opportunities in the pineapple supply chain in Benin

“…While seed potato supply systems of developing countries have received much academic attention in recent years (Gildemacher et al, 2009a,b;Hirpa et al, 2010Hirpa et al, , 2012Ortiz et al, 2013;Schulte-Geldermann et al, 2012), and have been the focus of much work by the International Potato Centre (CIP), much less attention has been paid to the linkage between the improved seed supply chain and the ware potato supply chain. This paper aims to combine economics/marketing and agronomic concepts to answer the above research questions.…”

“…For example, a positive seed potato selection study undertaken in Kenya showed that positive seed potato selection increases the yield of potato by ware growers by about 34% (Gildemacher et al, 2012). The current practice in the informal seed system is suboptimal and needs improvement.…”

“…Local storage methods are largely sub-optimal because seed potatoes stored in local storage have fewer, longer and weaker sprouts that have low vigour at planting (i.e. are physiologically too old) (Gildemacher, 2012). In the alternative seed system, seed growers used the DLS method.…”

Challenges of Seed Potato (<i>Solanum tuberosum</i> L.) Production and Supply System in Bangladesh - A Review

“…Selecting seed potatoes from healthy-looking mother plants (positive selection) assures lower incidences of PLRV (39%), PVY (35%) and PVX (35%). Positive selection out-yielded farmer selection by 30% irrespective of the agro-ecology, crop management, soil fertility, variety and quality of the starter seed, which may benefit all smallholder potato producers who select seed potatoes at same stage from their own fields, and thus could be incorporated routinely in agricultural extension efforts (Gildemacher et al, 2011;Schulte-Geldermann et al, 2012).…”