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The second phase of the Yam Improvement for Income and Food Security in West Africa (YIIFSWA II) project was implemented through a strong collaboration between research and private sector. Private seed companies were provided with a wide variety of training and development activities on good agronomic practices (GAPs). However, the effects of the training activities were yet to be evaluated. This paper evaluated the contribution of the training on high-quality seed yam production through paying particular attention to how it was tailored to the needs of various farmers, and how the knowledge gained was transferred to the field. The study employed an applied Kirkpatrick model and descriptive statistics to measure the indicators of training effectiveness. Results from a statistical population of 172 farmers using 179 demonstration fields showed that the farmers’ training on GAPs was effective, based on four criteria of the Kirkpatrick training evaluation process. The satisfactory results at the beginning of the hierarchical model have implications on the satisfactory results at the end. Improving the effectiveness of a training depends on defining factors such as (i) Training based on satisfaction in meeting the needs of your trainees and the seed production business; (ii) Training based on learning objectives in improving the trainees’ skills and knowledge; and (iii) Training based on learner attitude change in applying new skills and knowledge in the fields. Conclusions drawn from this study indicated that the training was a reasonable value-added mechanism of improved agricultural knowledge and practices for enhancing high-quality seed yam production in Nigeria.

Yams are staples in West Africa. They are propagated from tubers in an informal seed system. This encourages a build-up of diseases, and necessitates the rapid development of a formal seed system where certified seeds are functional. Although few reports exist on the use of meristem culture to generate pathogen-free yam, the success rate for the most economically important species in the sub-region, Dioscorea rotundata, for the most prevalent viruses is inadequate. To generate pathogen-free yam planting materials, the relative efficiency of tissue culture and positive selection was compared. Twenty-one asymptomatic yam plants were positively selected from 8187 stands of five landraces. Five of these stands were tested virus-negative by multiplex polymerase chain reaction (PCR) for Yam mosaic virus (YMV), Yam mild mosaic virus (YMMV) and Cucumber mosaic virus (CMV), and by PCR for the genus Badnavirus (BV), giving 0.08% success. Single nodes of the positively selected stands were used to establish in vitro plantlets, which were screened onto bacteriological indexing medium. The same was done for meristem- and node-derived plantlets of the improved variety TDr 95/19158. Incidence of endophytes ranged from 18 to 32% in the nodal plantlets while it was 0% in the meristem-derived plantlets. The effect of meristem culture combined with thermotherapy on the virus infection status was determined using virus-tested, one week old in vitro plantlets of eight improved genotypes. These in vitro plantlets were incubated at 36 ± 0.5°C and 16 h photoperiod for 21 days, after which meristems were excised, regenerated into plantlets and re-tested for viruses. Seventy-three percent of the samples were recovered from YMV but the effect on BV was inconsistent. Positive selection can be used as a palliative in generating quality declared seed but meristem culture combined with thermotherapy is more efficient for generating certified seed tubers of yam.