Practices and damages encountered by wholesale traders during 'Kponan' yams (Dioscorea cayenensis-rotundata) storage in Abidjan, Côte d'Ivoire

Abstract

Yam wholesalers who practice speculative storage sometimes suffer significant losses the level of which has been little studied. Thus, this work was carried out to study the practices and deterioration factors of 'Kponan' yam during storage. To achieve this, 51 yam wholesalers in 4 communes of Abidjan (Abobo, Adjamé, Yopougon and Treichville) were interviewed using a survey form. The data showed that according to storage practices, yams are preferentially grouped by variety (100%) and old yams separately (88.2%). Wholesalers (94.1%) regulate the storage temperature either by fans (23.5%), by air openings in the wall (25.5%), or by fans and air openings in the wall (45.1%). Decay was the most common damage among all wholesalers (100%), followed by weight loss (52.9%), mold (35.3%), injury (29.4%), cracking (23.5%), and sprouting (17.6%). Heat was the main cause of yam damage, followed by moisture (82.3%), animals (31.4%), field storage conditions (17.6%), chemical use during cultivation (17.6%) and sprouting (17.6%). This study shows that the storage and temperature control techniques employed by wholesalers are far from mitigating the heat that is the main cause of damage to 'Kponan' yam (Dioscorea Cayenenis-rotundata) during storage.

Impacts of Field Harvesting and Conservation Practices on the Physical Quality of Yam “<i>Kponan</i>” (<i>Dioscorea cayenensis-rotundata</i>) of Côte D’Ivoire

“…After the 3 months of field storage, rot (22.86% -60.00%) was the most significant injury recorded. These results corroborate those of several authors [16] [23], who identified rot and weight loss as the main damages recorded when "Kponan" was kept under the influence of heat. Losses attributed to more than 30% to 50% during field storage were attributable to insects, rats and chemicals [23].…”

“…Other factors such as heat, mold, animals (rodents and insects), germination, field storage conditions and chemicals use [23], coupled with soil quality and fallow time [16], may also reduce the storage time of "Kponan" yam. According to these authors, the combination of cultivation methods, conservation methods, soil poverty and short fallow time are the factors implicated in reducing the life span of "Kponan" yam in conservation.…”

“…Among the yams, the varieties of the Dioscorea cayenensis-rotundata complex are much more susceptible to rot [12]. Of these varieties, "Kponan" is most popular among consumers in the city of Abidjan [14] [15] [16], but most prone to rotting during storage [16].…”

Impacts of storage practices on the physical, culinary and sensory quality of Kponan yam (Dioscorea cayenensis‐rotundata) from Côte d'Ivoire during storage

“…13 Unfortunately, the Kponan variety, which is the most prized of this complex by consumers, [14][15][16] is the most prone to rot during conservation and storage. 16 Kponan yams sold on Abidjan wholesale markets comes from six geographical origins, the main ones being Bondoukou (60%), Bouna (33.3%) and Kouassi-Kouassikro (6.7%). 15 Despite the importance of yams in Côte d'Ivoire's food system, annual production is still insufficient to meet food needs, due to tuber storage, which causes weight losses ranging from 65% to 85% 17 and losses of up to 50% of the harvest caused by dehydration, harvest wounds, pests, rats and the use of chemicals.…”

“…15 Despite the importance of yams in Côte d'Ivoire's food system, annual production is still insufficient to meet food needs, due to tuber storage, which causes weight losses ranging from 65% to 85% 17 and losses of up to 50% of the harvest caused by dehydration, harvest wounds, pests, rats and the use of chemicals. 13,15,16,18 As a result, these losses greatly reduce yields and, consequently, the quantity of tuber seeds, sometimes leading to the disappearance of certain varieties. According to several authors, 11,19 growing, harvesting and storing techniques of Kponan yam in the field have an impact on its shelf life.…”