Search

Supplemental material, sj-docx-1-oag-10.1177_00307270211058209 for Yam seed system characteristics in Nigeria: Local practices, preferences, and the implications for seed system interventions by Esm�� Stuart, Asrat Asfaw, Patrick Adebola, Norbert Maroya, Alex Edemodu, Tunde Adeosun, Robert Asiedu and Conny Almekinders in Outlook on Agriculture

The study employed choice experiment and latent class model to assess farmers’ preferences for seed yam certification system and their willingness to pay for certified seed yam in selected yam producing Districts in Ghana. A total of 9120 choice experiments were conducted to elicit data from 380 yam farmers. The study identified three classes/ market segments of farmers regarding preferences for Pona seed yam. The results show that farmers have more utility towards fully certified seed yam and are willing to pay GH¢719.60 (US$189.4) for a bunch (100 tubers weighing about 45kg) of fully certified seed yam. However, farmers were found to have high utility towards medium-sized Pona seed yam and are willing to pay a premium of GHC¢12.5 (US$3.3) for this attribute. The study has demonstrated high potential for the commercialization of seed yam production in Ghana through a formal seed yam certification system.

The study examined the effect of farmers’ perception about the quality of seed yam typically used for cultivation on their preferences for certified seed yam. Heckman’s sample selectivity probit model was applied on survey data collected from 380 yam farmers. The study found that farmers generally agree that the use of certified seed yam would help to improve yield because of minimum to no disease/pest infestation. Farmers expressed their willingness to purchase certified seed yam if the price is about 26% higher than those supplied from the informal system in as much as the quality can be assured. The study found that farmer educational level, experience, access to extension services and household incomes were factors influencing farmers’ perception about quality of seed yam cultivated. Variables such as age, educational level and income were also found to be factors that influence farmers’ preference for certified seed yam. The results were similar for both Pona and other white yam varieties. The study recommends promotion of farmer education through increased access to extension services on seed quality assessment together with other agronomic practices including farmer field schools, to help improve their ability to assess the quality of seed yam obtained from other sources as well as increase their preference for certified seed yam.

A bold step to addressing myriads of constraints affecting yam productivity was achieved through Yam for Income and Food Security in West Africa (YIIFSWA) project. The project has embarked on a series of activities culminating in the development, deployment and disseminating intervention options/technologies in Nigeria and Ghana. This paper assesses the potential economic impacts, the number of beneficiaries and poverty reduction through these agricultural technologies/intervention options. The land area coverable by the technologies ranged 320,000–650,000 ha in the two countries. The land area under varieties for adaptation to environments with low soil fertility was the highest followed by resistance to nematode cultivars. The net present value (NPV) ranged $144 million–$616 million and was highest for YIIFSWA diagnostic tool and temporary immersion bioreactor. Crop management and postharvest practices option had the lowest benefit-cost ratios of 6.0 and 20.03 while the aeroponics option had the highest benefit cost ratio of about 36.90. Not less than 750, 000 would be brought out of poverty by these technologies. The technologies are expected to reach not less than 20 million households by 2037 in Nigeria and Ghana. The technologies are more responsive to change in adoption rate than change in costs. Overall, while the potential economic gains are considerable, realization of these gains depends on the efficiency and effectiveness of extension and input supply systems. Concerted extension efforts are needed to drive the use of these intervention options. Moreover, considerable technical advice would also be needed to explain how to apply them

A closed-tube reverse transcription loop-mediated isothermal amplification (CT-RT-LAMP) assay was developed for the detection of yam mosaic virus (YMV, genus Potyvirus) infecting yam (Dioscorea spp.). The assay uses a set of six oligonucleotide primers targeting the YMV coat protein region, and the amplification products in YMV-positive samples are visualized by chromogenic detection with SYBR Green I dye. The CT-RT-LAMP assay detected YMV in leaf and tuber tissues of infected plants. The assay is 100 times more sensitive in detecting YMV than standard RT-PCR, while maintaining the same specificity. Electronic supplementary material The online version of this article (10.1007/s00705-018-3706-0) contains supplementary material, which is available to authorized users.