Storage rot of seed yam resulting from speargrass injuries

Postharvest rot due to injury is a major contributing factor to the declining quality of stored seed yams ( Dioscorea spp.). Among the several known injuries, the piercing effect of speargrass rhizomes has become a serious constraint for yam production in Ghana. The objective of this study was to assess injuries on seed yams resulting from piercing of speargrass rhizomes and their effects on postharvest rots in Ghana. Eighty farmer fields from Mem, Watro, Asanteboa and Abour in the Atebubu-Amantin Municipal in the Bono East Region of Ghana were screened for speargrass incidence and injury on harvested tubers, for laboratory analysis of pathogens in 2016 and 2017. The tubers were sorted into four categories of seed yam based on weight. Thirty seed yams each of two selected white yam cultivars (Dente and Kpamyo) with visible speargrass rhizome-pierced-tubers (VSRPT) and non-speargrass rhizome pierced healthy tubers (NSRPHT) were randomly selected and stored in a ban for weekly assessment of rot. The rotten tissues from the localised area of VPSRT were subjected to pathological investigations in the laboratory. The incidence of injury seemingly increased with increasing tuber weight. It was 0% for < 100 g samples and averagely 14% for > 1 kg samples, irrespective of cultivars and locations. Incidence of rot from NSRPHT sample was observed 5 weeks after storage (WAS) for both cultivars; and 2 WAS from the VSRPT sample and 40% higher than NSRPHT at 8 WAS. Eight and six known rot pathogens were isolated from the rotten tissues of VSRPT of Dente and Kpamyo, respectively. Injury from the piercing of speargrass rhizome significantly contributed to hastening of tuber rots; while tuber injury increased with increasing speargrass density. Appropriate management of speargrass is essential for commercial seed yam growers to reduce tuber damage which affects yam quality, storage and marketing.La pourriture post-r\ue9colte due \ue0 une d\ue9chirure est un facteur majeur contribuant \ue0 la baisse de la qualit\ue9 des ignames des semences stock\ue9es ( Dioscorea spp.). Parmi les nombreuses d\ue9chirures connues, l\u2019effet per\ue7ant des rhizomes de la gerbe d\u2019herbe est devenu une contrainte s\ue9rieuse pour la production d\u2019igname au Ghana. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer les d\ue9chirures sur les ignames de semence r\ue9sultant du per\ue7age des rhizomes de gerbe d\u2019herbe et leurs effets sur les pourritures post-r\ue9colte au Ghana. Quatre-vingts champs d\u2019agriculteurs de Mem, Watro, Asanteboa et Abour dans la municipalit\ue9 d\u2019Atebubu-Amantin dans la region de l\u2018 Est de Bono au Ghana ont \ue9t\ue9 examin\ue9s pour d\ue9terminer l\u2019incidence et les dommages de la gerbe d\u2019herbe sur les tubercules r\ue9colt\ue9s, pour une analyse en laboratoire des agents pathog\ue8nes en 2016 et 2017. Les tubercules ont \ue9t\ue9 tri\ue9s en quatre cat\ue9gories d\u2019igname de semence en fonction du poids. Trente ignames de semence de chacun des deux cultivars s\ue9lectionn\ue9s d\u2019igname blanche (Dente et Kpamyo) avec des tubercules perc\ue9s de rhizome de gerbe d\u2019herbe (VSRPT) et des tubercules sains perc\ue9s de rhizome non- gerbe d\u2019herbe (NSRPHT) ont \ue9t\ue9 s\ue9lectionn\ue9s au hasard et stock\ue9s dans une interdiction pour une \ue9valuation hebdomadaire de la pourriture . Les tissus pourris de la zone localis\ue9e de VPSRT ont \ue9t\ue9 soumis \ue0 des investigations pathologiques en laboratoire. L\u2019incidence des d\ue9chirures a apparemment augment\ue9 avec l\u2019augmentation du poids des tubercules. Il \ue9tait de 0% pour les \ue9chantillons <100 g et de 14% en moyenne pour les \ue9chantillons > 1 kg, quels que soient les cultivars et les emplacements. L\u2019incidence de pourriture de l\u2019\ue9chantillon NSRPHT a \ue9t\ue9 observ\ue9e 5 semaines apr\ue8s stockage (WAS) pour les deux cultivars; et 2 WAS de l\u2019\ue9chantillon VSRPT et 40% plus \ue9lev\ue9s que NSRPHT \ue0 8 WAS. Huit et six agents pathog\ue8nes de la pourriture connus ont \ue9t\ue9 isol\ue9s respectivement dans les tissus pourris du VSRPT de Dente et de Kpamyo. Les d\ue9chirures caus\ue9es par le per\ue7age du rhizome de gerbe d\u2019herbe ont consid\ue9rablement contribu\ue9 \ue0 acc\ue9l\ue9rer la pourriture des tubercules; tandis que les dommages aux tubercules augmentaient avec l\u2019augmentation de la densit\ue9 de la gerbe d\u2019herbe. Une gestion appropri\ue9e de la groseille verte est essentielle pour les producteurs commerciaux d\u2019ignames de semence afin de r\ue9duire les dommages aux tubercules qui affectent la qualit\ue9, le stockage et la commercialisation des ignames

Enhancing productivity of farmer-saved seed yam in Ghana: Positive selection and neem leaf powder factors

Recycling of diseased and pests infested seed yam ( Dioscorea spp.) has resulted in drastic yield reductions in yam production. The objective of this study was to determine the effect of positive selection on the quality of farmer-saved seed yam and also evaluate the effect of neem leaf powder in managing plant parasitic nematodes damage to yam. Two farming systems namely; Positive selection (PS) and Farmer practice (FP) and two soil amendment regimes; neem leaf powder at 20 g stand-1 (NA20) and no neem amendment (NA0) were tested on one variety of yam (Dente). A 2 x 2 x 1 factorial study, mounted on a randomised complete block design in a split plot arrangement was conducted in four replications. Positive selection occupied main plots; while Farmer practice occupied sub-plots. The study was conducted in eight communities located in two municipalities of Ghana, during 2015-2017. Parameters evaluated included Yam Mosaic Virus incidence and severity, incidence and severity of nematode cracks and galling on yam tubers, plant establishment and yield of yam. It was observed that Yam Mosaic Virus (YMV) disease incidence decreased from 38% in 2016 to 31% in 2017 in PS plots as a result of using virus-free planting materials. However, in FP plots, it increased from 67% in 2016 to 72% in 2017. Neem leaf powder amendment resulted in significantly (P< 0.05) low tuber galling (7%) compared with 40% in unamended plots. Similarly, PS plots yielded 7.7 t ha-1 compared to 5.9 t ha-1 in FP fields. In conclusion, Positive selection out-yielded FP by 30.5%; while PS-neem leaf powder interaction resulted in 38.5% over and above FP without neem amendment.Le recyclage des semences d\u2019igname ( Dioscorea spp.) contamin\ue9es par des maladies et des parasites a entra\ueen\ue9 une r\ue9duction drastique du rendement de la production d\u2019igname. L\u2019objectif de cette \ue9tude \ue9tait de d\ue9terminer l\u2019effet de la s\ue9lection positive sur la qualit\ue9 des semences d\u2019igname conserv\ue9es par les agriculteurs et \ue9galement d\u2019\ue9valuer l\u2019effet de la poudre de feuilles de neem dans la gestion des dommages caus\ue9s par les n\ue9matodes parasites des plantes. Deux syst\ue8mes agricoles \ue0 savoir; S\ue9lection positive (PS) et pratique paysanne (PF) et deux r\ue9gimes d\u2019amendement du sol; De la poudre de feuille de neem \ue0 20 g du stand-1 (NA20) et aucun amendement de neem (NA0) ont \ue9t\ue9 test\ue9s sur une vari\ue9t\ue9 d\u2019igname (Dente). Une \ue9tude factorielle de 2 x 2 x 1, mont\ue9e sur une dispositif en\ua0blocs al\ue9atoires complets dans un arrangement en parcelles divis\ue9es, a \ue9t\ue9 men\ue9e en quatre r\ue9p\ue9titions. S\ue9lection positive occup\ue9e parcelles principales; tandis que la pratique paysanne occupait des sous-parcelles. L\u2019\ue9tude a \ue9t\ue9 men\ue9e dans huit communaut\ue9s situ\ue9es dans deux municipalit\ue9s du Ghana en 2015-2017. Les param\ue8tres \ue9valu\ue9s comprenaient l\u2019incidence et la gravit\ue9 du virus de la mosa\uefque de l\u2019igname, l\u2019incidence et la gravit\ue9 des fissures de n\ue9matode et le grippage des tubercules de l\u2019igname, l\u2019\ue9tablissement de la plante et le rendement de l\u2019igname. Il a \ue9t\ue9 observ\ue9 que l\u2019incidence de la maladie caus\ue9e par le virus de la mosa\uefque \ue0 l\u2019igname (YMV) avait diminu\ue9 de 38% en 2016 \ue0 31% en 2017 dans les parcelles PS gr\ue2ce \ue0 l\u2019utilisation de mat\ue9riel de plantation d\ue9pourvu de virus. Cependant, dans les parcelles de PF, il est pass\ue9 de 67% en 2016 \ue0 72% en 2017. L\u2019amendement de poudre de feuille de Neem a entra\ueen\ue9 une r\ue9duction significative du galles des tubercules (P <0,05) (7%) par rapport \ue0 40% dans les parcelles non modifi\ue9es. De m\ueame, les parcelles de PS ont produit 7,7 t ha-1, contre 5,9 t ha-1 dans les champs de PF. En conclusion, la s\ue9lection positive a eu un rendement sup\ue9rieur de 30,5% \ue0 celui de la PF; tandis que l\u2019interaction de la poudre de feuille PS-neem a eu pour r\ue9sultat 38,5% de plus que FP sans amendement de nee

Demonstrating the efficacy of existing yam technologies in the forest-savannah transition zone of Ghana

Open Access ArticleImproved technologies (row planting, ridging, seed treatment, weed management, fertilizer application) with a proven record of sustained productivity for yam production are imperative for food security. This study promotes the efficacy of these existing improved agronomic practices using a farmer-based participatory approach in some selected major yam-growing areas in the forest–savannah transition zone of Ghana. The improved agronomic practice treatment included use of ridging as seedbed, seed treatment before planting, fertilizer application at a rate of 30:30:36 N:P2O5: K2O kg/ha plus 15 kg/ha Mg and 20 kg/ha S as MgSO4 and the use of minimum stakes (trellis; 30-50% fewer stakes used by farmers). This was compared with farmers’ practice, which consisted of mounding, no fertilizer application, and no seed treatment. A significantly (p ≤ 0.01) higher yam yields (more than 60%) were observed for the improved agronomic practice over the farmers’ practice at Ejura, Atebubu, and Kintampo which are major yam-growing communities of Ghana. Sensory evaluation showed that the culinary quality of fertilized yam was as good as unfertilized yam. The contribution of existing improved yam production practices in the selected yam communities of Ghana was quantified in terms of their productivity and economic benefit to smallholder farmers

Influence of Fertilizer Application on Postharvest Storage of Two White yam (Dioscorea rotundata) Cultivars in Ghana

Yam growers across major growing areas are being encouraged to increase tuber yield through the application of fertilizer at the recommended rates and periods. Ghana, the leading exporter of yam in Africa, is currently facing the problem of poor tuber storability. Some actors along the food value chain attribute most storage rots to the application of fertilizer by farmers. This study was conducted to investigate in to the claim that fertilizer application has an effect on the shelf life of white yam tubers. Four fertilizer application models were tested on two white yam cultivars, Serwa and TDr95/19177. No fertilizer application served as the control experiment. Healthy- looking white yam tubers of the two cultivars were randomly selected from a fertilizer application trial at Ejura-Sekyedumasi District in Ashanti Region of Ghana and storage rot experiment conducted at CSIR-CRI(onstation) between January and July, 2015.The experimental design was a Split plot design with three replications. The main plot represented the two cultivars whilst the sub-plot was the fertilizer models. Initial parameters taken were tuber weight, yield and moisture content. Temperature and relative humidity were periodically recorded. Rot assessment were done at 3rd, 4th, 5th and 6th months of storage. Rot analysis parameters taken were tuber weight, number of rotten tubers, rot initiation point, rot type and associated pathogens. Percent incidence and severity were determined and used for the analysis and interpretations. Severity data was subjected to statistical analysis using the Genstat statistical package 9.2, after the results was transformed using the square root transformation. Major fungi identified from rotten tissues over the period were Lasiodiplodia the obromae, Fusarium oxysporum, Penicilliumsp., Rhizopussp., Aspergillus flavus. Fifty-four percent of rotten tubers were the dry rot type. There were similarities in the incidence of rot among all treatments. There was no significant difference in terms of rot severity among the fertilizer application models as well as the control. However, varietal differences and tuber sizes were key factors identified as having effect on storage rots. Further studies on commercial white yam varieties such as Pona and Dente need to be conducted to evaluate the influence of fertilizer application on their shelf lives. .Key words: fertilizer application, storage rots, white yams and shelf life. Influence de l'application d'engrais sur le stockage post-récolte de deux variétés d'igname blanche (Dioscorea rotundata) au GhanaLes producteurs d'igname dans les principales zones de culture sont encouragés à augmenter le rendement des tubercules par l'application déngrais aux taux et périodes recommandés. Le Ghana, qui est le premier exportateur d'igname en Afrique, est actuellement menacé par une faible capacité de stockage des tubercules. Certains acteurs de la chaîne de valeur alimentaire attribuent la plupart des pourritures de stockage à l'application d'engrais par les agriculteurs. Cette étude a été menée pour étudier l'allégation selon laquelle l'application d'engrais a un effet sur la durée de conservation des tubercules d'igname blanc. Quatre modèles d'application d'engrais ont été testés sur deux cultivars d'igname blanche, Serwa et TDr95 / 19177. Aucune application d'engrais n'a servi d'expérience de contrôle. Des tubercules d'igname blanche d'apparence saine des deux cultivars ont été choisis au hasard dans un essai d'application d'engrais dans le quartier d'Ejura-Sekyedumasi dans la région d'Ashanti au Ghana et une expérience de pourriture du stockage a été effectuée à CSIR-CRI (en-station) entre janvier et juillet 2015. La conception expérimentale était une conception de parcelle avec trois répétitions. La parcelle principale représentait les deux cultivars tandis que la sous-parcelle était les modèles d'engrais. Les paramètres initiaux ont été le poids du tubercule, le rendement et la teneur en humidité. La température et l'humidité relative ont été enregistrées périodiquement. L'évaluation de la pourriture a été effectuée aux 3e, 4e, 5e et 6e mois d'entreposage. Les paramètres d'analyse de la pourriture mesurés étaient le poids des tubercules, le nombre de tubercules pourris, le point d'initiation de la pourriture, le type de pourriture et les pathogènes associés. L'incidence et la gravité en pourcentage ont été déterminées et utilisées pour l'analyse et les interprétations. Les données de sévérité ont été soumises à une analyse statistique en utilisant le progiciel statistique Genstat 9.2, après transformation des résultats en utilisant la transformation de la racine carrée. Les principaux champignons identifiés à partir des tissus pourris au cours de la période étaient: Lasiodiplodia l'obromae, Fusariumoxysporum, Penicilliumsp., Rhizopussp., Aspergillusflavusetc. Environ 54% des tubercules pourris étaient des type pourriture sèche. Il y avait des similitudes dans l'incidence de la pourriture parmi tous les traitements. Il n'y avait pas de différence significative en termes de sévérité de pourriture parmi les modèles d'application d'engrais ainsi que le contrôle à P <0,05. Cependant, les différences variétales et la taille des tubercules étaient des facteurs clés identifiés comme ayant un effet sur les pourritures de stockage. D'autres études sur des variétés commerciales d'ignames blanches telles que Pona et Dente doivent être menées pour évaluer l'influence de l'application d'engrais sur leurs durée de conservation.Mots clés: application d'engrais, pourritures de stockage, ignames blanches et durée d

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

Background Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery. Methods This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy. Results Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51–19.97) than planned admissions (OR: 2.32, 95% CI: 1.43–3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8–51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI. Conclusions After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies

Body mass index and complications following major gastrointestinal surgery: A prospective, international cohort study and meta-analysis

Aim Previous studies reported conflicting evidence on the effects of obesity on outcomes after gastrointestinal surgery. The aims of this study were to explore the relationship of obesity with major postoperative complications in an international cohort and to present a metaanalysis of all available prospective data. Methods This prospective, multicentre study included adults undergoing both elective and emergency gastrointestinal resection, reversal of stoma or formation of stoma. The primary end-point was 30-day major complications (Clavien–Dindo Grades III–V). A systematic search was undertaken for studies assessing the relationship between obesity and major complications after gastrointestinal surgery. Individual patient meta-analysis was used to analyse pooled results. Results This study included 2519 patients across 127 centres, of whom 560 (22.2%) were obese. Unadjusted major complication rates were lower in obese vs normal weight patients (13.0% vs 16.2%, respectively), but this did not reach statistical significance (P = 0.863) on multivariate analysis for patients having surgery for either malignant or benign conditions. Individual patient meta-analysis demonstrated that obese patients undergoing surgery formalignancy were at increased risk of major complications (OR 2.10, 95% CI 1.49–2.96, P < 0.001), whereas obese patients undergoing surgery for benign indications were at decreased risk (OR 0.59, 95% CI 0.46–0.75, P < 0.001) compared to normal weight patients. Conclusions In our international data, obesity was not found to be associated with major complications following gastrointestinal surgery. Meta-analysis of available prospective data made a novel finding of obesity being associated with different outcomes depending on whether patients were undergoing surgery for benign or malignant disease