IMPACT OF THE ADAPTED YAM MINISETT TECHNIQUE ON WARE YAM (DIOSCOREA ROTUNDATA) PRODUCTION UNDER FARMER-MANAGED CONDITIONS IN NIGERIA

Abstract

White yam (Dioscorea rotundata) is a major root crop grown throughout West Africa and a major limitation on its production is the availability of good quality (i.e. free of pests and diseases) planting material; notably seed yams. AYMT is a process by which farmers can produce good quality seed yams using setts treated with a pesticide dip. While previously published studies have focussed on the agronomy of the sett-to-seed yam process there has been no work done on the seed-to-ware yam stage which is critical in terms of income and livelihood for yam farmers throughout West Africa. This paper addresses this significant gap in knowledge and provides the first published evidence obtained under entirely farmer-managed conditions in Africa that shows seed yams produced via the AYMT can generate significant agronomic benefits, including better germination, tuber numbers and tuber weights, for ware yam growers in Nigeria.

Factors Influencing the Agronomic Performance of the Adapted Yam Minisett Technique in Nigeria – Planting Date and Gender of the Farmer

“…The positive impact on tuber weight of treating yam setts before planting is clear from the research presented here and indeed has been noted in previous publications (Morse and McNamara, 2015;2016;Morse et al, 2009). The results also confirm a point made before regarding the effect of pesticide treatment on tuber weight rather than tuber number (Morse and McNamara, 2015).…”

“…Akpaji appears to have lower average tuber weight, weight of tubers/sett planted and number tubers/sett planted relative to the other two varieties. These findings regarding the impact of pesticide treatment and variety were expected and indeed were highlighted in the results of previous work utilising AYMT demonstration plot data from 2013 and 2014 (Morse and McNamara, 2015; 2016).…”

“…The use of vine cuttings has potential but has not yet been employed on a large scale (Asante et al ., 2011) and in practice, most farmers employ the use of tuber-derived material – either seed yams or setts – and it has been well established that multiplication ratios for yam are relatively low, ranging from 1:4 to 1:8 (Alvarez and Hahn, 1984), and shoot emergence tends to be uneven so that a field of planted seed yams or setts will have plants at various stages of growth (Otoo et al ., 1987). Planting poor quality planting material can be assumed to impact on subsequent ware crop yield and tuber quality, and a recent paper suggests that under farmer-managed conditions, the use of good quality seed yams can make a significant difference to ware yam yield (Morse and McNamara, 2016) and unsurprisingly good quality seed yams sell for a premium price in markets (McNamara et al ., 2012).…”

Environmental and economic impacts of pesticide treatment in the Yam Minisett Technique

“…An example of agronomic studies for the AYMT can be found in Morse andMcNamara (2016, 2018b). There have also been studies on the agronomic impact of using seed yams produced from AYMT on ware yam production (Morse and McNamara, 2017). However, while the agronomy of YMT and AYMT has been well-explored, there is still a relative paucity of cost-benefit analyses (CBA) of both YMT and AYMT, especially under farmermanaged conditions rather than researcher-controlled experimental plots.…”

“…The assumption here is that seed yams produced via any of the techniques is of a better quality than planting material the farmer would otherwise have access to. The agronomic benefits of using quality seed yams produced from AYMT for ware yam production have been explored by Morse and McNamara (2017) but not the economic impacts. Third, almost all of the studies to date, be they based on experiments, surveys or monitoring farmer-managed plots, have not compared the economic performance of untreated and treated setts.…”