Agronomic and economic performance of seed yam production using minisetts in the middle belt of Nigeria

Abstract

White yam (Dioscorea rotundata) is an important tuber crop of West Africa and the Caribbean, and one the key limiting factors in its production is the availability of good quality planting material. The Adaptive Yam Minisett Technique (AYMT) was designed to help overcome this constraint. The paper presents an analysis of agronomic and economic data collected across four years (2013 to 2016) of AYMT plots planted in two areas within the middle-belt of Nigeria. Of the 136 plots that were established, 11% were lost to flooding and damage from Fulani cattle. Mean yield was 13.16 t/ha, 17,747 tubers/ha and the mean tuber weight was 0.73 kg. Plot yield declined with an increase in planting time, while plots owned by female farmers were on average planted later than those owned by their male counterparts; this helps explain the effect of gender noted in a previous study. Differences in yield were also noted between the two areas, which could also partly be explained by differences in planting time. The plots were profitable, with a mean cost over the four years of Naira 915,196/ha, revenue of Naira 3,197,786/ha and gross margin of Naira 2,282,591/ha

Propagation of lusala(Dioscorea hirtiflora), a wild yam, forin situandex situconservation and potential domestication

“…Visible shoot buds on tubers denote the end of the dormancy period (Awologbi and Hamadina, 2016). Larger whole tubers or larger minisetts of cultivated yams show greater emergence, and the resultant plants survive better than those from smaller ones (Aighewi et al, 2015;Enyi, 1972;Law-Ogbomo and Remison, 2009;Morse and McNamara, 2018). Proximal minisetts emerge better than those cut from distal and middle regions (Orkwor and Ekanayake, 1998;Passam, 1977).…”

“…Suitable propagation methods are necessary in the domestication of any plant (Aighewi et al, 2015) and for plant genetic resources conservation and utilization. In cultivated yams, propagation often involves the selection of small whole tubers (seed yams) from the ware crop or minisetts cut from large tubers to provide planting material (Morse, 2018;Morse and McNamara, 2018), while nodal vine cuttings are grown to produce mini-tubers for use as seed yams in research stations (Aighewi et al, 2015;Balogun and Gueye, 2014). The propagation of cultivated yams from small whole tubers diverts as much as 30% of the annual harvest from consumption to future crop production (Ekanayake and Asiedu, 2003).…”

“…This cost is reduced by propagation from minisetts (Ekanayake and Asiedu, 2003). However, there is a limit to reducing sett size for optimal propagation: the smaller the setts the smaller the tubers produced (Morse, 2018;Morse and McNamara, 2018).…”

“…The length of vines and number of leaves (Table 2) were greater from: tubers with visible shoot buds and small or large tubers (Experiment 1); re-tuberized tubers (Experiment 2); larger minisetts and/or those cut from the proximal end of tubers (Experiments 4 and 5); and minisetts from tubers with visible shoot buds (Experiment 5). Similarly in cultivated yams, bigger minisetts or tubers show better growth (Aighewi et al, 2015;Enyi, 1972;Law-Ogbomo and Remison, 2009;Morse and McNamara, 2018), and proximal minisetts provide greater growth than minisetts from middle and distal regions (Orkwor and Ekanayake, 1998;Passam, 1977). Lusala tuber yield from minisetts was lower than that from tubers ( Figure 2).…”

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

“…Also, if these plots are part of a demonstration and farmer-training programme then there may still be some influence from 'outsiders' rather than farmers having complete control. An example of this 'farmer managed' approach is provided by Morse and McNamara (2018a) for two areas; Idah (Kogi State) and Amoke (Benue State) across 4 years (2013-to 2016). The plots included in this study were primarily intended as demonstrations and to provide yam farmers with a taste of the potential of AYMT for producing quality seed yams.…”