Food and Nutrition Security Initiative Conference

Efficacy of Bio-based Extracts on Shelf-Life and Quality Attributes of orange fruits during storage in Makurdi

by Bob Agbatar - bobagbatar(at)gmail.com

Over the years, extending the shelf life of harvested oranges has been a major challenge in Sub-Sahara Africa. Most of the recommended postharvest treatment methods and technologies developed over the years for elongating shelf life and maintaining postharvest qualities of orange fruits are not accessible and affordable to the local farmers in most developing countries, including Nigeria. Even though lots of researchers have worked on various synthetic chemicals like mancozeb, benomyl and carbendazim to control the postharvest diseases of fruits and to improve its storage life, the use of these synthetic preservatives poses serious health hazards and leads to environmental pollution. With the growing health consciousness among people and increasing consumer demand for pesticide residue free agricultural commodities, I am motivated to find better alternatives that are cost effective, non-toxic and eco-friendly, with low residual action, to prevent disease infections and maintain post-harvest quality of oranges.

Functional trait diversity and drought tolerance of enset - a key food security crop in Ethiopia

by Rachel Chase - R.R.Chase(at)gre.ac.uk

Enset (Ensete ventricosum (Welw.) Cheesman) is a tall herbaceous perennial crop grown by over 20 million people in the densely populated highlands of southwest Ethiopia. It has been called the ‘tree against hunger’ for its importance in food security. The entire plant is used, mainly as a carbohydrate-rich food source, but also for fibre, shelter, medicine, mulch and animal feed. With its low labour input, high yield, long storage potential, as well as its apparent tolerance to drought, enset has great potential for enhancing regional food security. However, despite its regional importance in a country that is vulnerable to climatic variability and periodic droughts, little is known about enset functional trait diversity and how it responds to environmental stress. To better understand this, my PhD project will 1) investigate enset production/yield dynamics and its response to past climatic trends in the context of the wider enset agrisystem; 2) characterize enset’s phenotypic traits to better understand landrace diversity, and how it varies across environments; 3) evaluate enset’s response to water stress to identify the extent and means of its drought tolerance; and 4) elucidate the genetic basis of enset phenotypic traits, including those linked to drought tolerance. Methodological approaches will include statistical analyses of crop and climate data, phenotypic characterization of hundreds of landraces in field collections and across altitudinal gradients, drought tolerance evaluations in the growtainer, greenhouse and field, and mapping phenotypic data collected in the study to emerging genetic data.

Research title: Development and Evaluation of Novel Diagnostic tests for African Yam Viruses

by Ruth Festus - R.O.Festus(at)greenwich.ac.uk

Yam is a major staple food crop in West Africa where it is essential for people's income generation and food security. The productivity of yam is constrained by a lack of a formal seed system, high costs associated with production, and pests and diseases. The propagation of yam through tuber setts and seed yam encourages the recycling of infected planting materials, contributing immensely to the high incidence and prevalence of yam viruses. There is, therefore, a need to increase the production of high-quality seed yam to enhance the crop's productivity and food security. The development of robust diagnostic tools is necessary to certify that mass propagated seed yam is virus-free to prevent the spread of viruses in the field. This research aims to develop, optimize, and validate a range of diagnostic tests for economically important yam viruses in West Africa. It will also focus on identifying and characterizing novel viruses using high throughput sequencing and bioinformatics approaches. A cost-effective and reliable next-generation sequencing workflow for the identification and characterization of yam viruses will be developed. An analysis of the accuracy, sensitivity, and cost-effectiveness of diagnostic methods will be used to recommend the most appropriate tool(s) for routine virus indexing of yam planting material.

The impact of organic fertilisers on the two dominant malaria vector species of Africa

by Harrison Lambert - harrison.lambert(at)greenwich.ac.uk

Organic fertiliser (OF) use is promoted in the System of Rice Intensification (SRI), a climate change-adapted method for cultivating rice with reduced inputs and higher yields. Many resource poor farmers also use OFs to supplement or fully replace industrial fertilisers. This has implications for malaria because rice irrigation can provide habitat for mosquito larvae. Little is understood about the impact of OFs on mosquito ecology in the context of SRI. It is important to understand whether SRI may have unintended impacts on mosquito abundance and potential knock-on effects on malaria transmission, in order to support transitions towards sustainable and climate-adapted agricultural techniques.

This research illustrates that cow and chicken dung, both of which are common OFs, have differential effects upon several important life history parameters in malaria vector mosquitoes. Their effects were examined in Anopheles arabiensis and Anopheles gambiae s.s, the two dominant malaria vectors of Africa. Cow dung showed little impact on survival and adult production, but increased the development rate in An. gambiae s.s., whereas chicken dung was highly detrimental to the juvenile mosquitoes of both species.

These results would imply that the use of cow dung as an OF in rice cultivation may benefit mosquitoes that inhabit the fields, leading to an increased abundance of adults and perhaps a higher burden of malaria in associated communities. Conversely, chicken dung may be a suitable method of control for Anopheline mosquitoes, in tandem with other integrated pest management methods, as it is generally detrimental to their survival, development, and production of adults.

Inland fisheries critical for the diet quality of children in sub-Saharan Africa

by Lydia O’Meara - L.C.OMeara(at)gre.ac.uk

The world will not reach Sustainable Development Goal 2 ‘Zero Hunger’ by 2030 unless we address micronutrient deficiencies, particularly amongst infants and children in developing countries. Fish are nutrient-rich and are valued to improve diet quality. We examined the diets of 6328 children in rural sub-Saharan Africa. Most children had inadequate diet diversity. Of those that did have higher diet diversity, 20% relied on eating fish from nearby inland fisheries as their only flesh food. Results suggest that food systems failed to provide fish or other flesh foods to 65% of rural children. To improve diet quality of children living more than 5 km from inland fisheries, strategies are needed to extend the reach of fish value chains and improve access to fish.

Watch a video presentation of this poster.

Read this Global Food Security article in ScienceDirect

Analysis of volatile metabolite profile of Neonectria ditissima infected apples

by Asoo Dorcas Yaji - A.D.Yaji(at)greenwich.ac.uk

Neonectria ditissima is a serious fungal pathogen of apple trees and fruits responsible for losses due to tree canker, loss of yield and fruit rots in storage. In-store sampling of volatile organic compounds (VOCs) allows for early detection of disease onset and warns growers of the need for early marketing of consignments of fruit with a high incidence of infection. This study was done to analyse VOC compounds associated with early N. ditissima infection in apples and to record changes in the VOCs profile of N. Ditissima throughout disease progression. Seven-day old cultures of N. ditissima grown on PDA amended with chloramphenicol (1 Vial (50mg) per 500ml medium) were used to wound inoculate gala apples, followed by incubation at 20oC for 49 days. Volatiles were captured on porapak columns at intervals of 2, 8, 14, 21, 28, 35, 42 and 49 days after inoculation. Samples were eluted with dichloromethane and run on GC-MS for analysis. Changes in VOCs associated with N. ditissima infected apples were detected by GC-MS showing esters as the most abundant compound. 2-Ethylbutyl acetate and Propanoic acid, 2,2-dimethyl-, hexyl ester were detected in the early stages of infection while Styrene, 3-Cyclohexen-1-ol, 4-methyl-1-(1-methylethyl)-, and Hexanoic acid, ethyl ester were only detected in late stages of infection. Discriminatory volatile metabolites detected at early stages of the infection could serve as possible biomarkers for early non-visual detection of N. ditissima in stored apples. Further studies are necessary for confirmation, development of suitable biomarkers and antifungal activities of the volatiles.

Evaluating options for the rational and healthy utilisation of small pelagic fish in Sub-Saharan Africa

by Stuart Bunting - S.W.Bunting(at)greenwich.ac.uk

Small pelagic fish from marine waters off the coast of Central and West Africa and across the African Great Lakes Region (AGLR) and their associated value chains sustain several million livelihoods. These catches are utilised for direct human consumption, to produce fish meal and fish oil for use in animal feeds and in the formulation of value-added products. Small fish from marine and inland waters constitute a valuable source of protein and micronutrients that could make a significant contribution to alleviating malnutrition and food insecurity in the region. Owing to population growth and economic development, demand for small pelagic fish is expected to rise, putting increased pressure on this finite resource. Considering this context, the purpose of this study was to speak to a representative range of people with a vested interest in the production and utilisation of small pelagic fish and ask them to rate the importance of 23 potential options for decision makers and future research. The Delphi method was adopted to engage with stakeholders in countries across the AGLR (Malawi, Uganda), Central-West Africa (Congo, Ghana, Sierra Leone) and North-West Africa (Gambia, Mauritania, Senegal). Responses were received from 150 and 115 participants in Rounds 1 and 2, respectively. Mean ratings in Round 2 ranged from 4 to 9.76 and a value for Kendall’s W of 0.646 indicated that the strength of agreement amongst participants was moderate to strong. Priorities identified included environmental audits for fishmeal processors, developing alternative feed ingredients, better monitoring of fish stocks and post-harvest activities.

Studies on Microbial Profiles and Control of Postharvest Rot of Dioscorea alata and Dioscorea rotundata using Plants Extracts

by Dooshima Shiriki - dshiriki(at)bsum.edu.ng

In many African countries, including Nigeria, post harvest tuber losses can reach 50%. One of the main causes of postharvest losses of yams are microorganisms. This research aimed to isolate and identify the various microorganisms responsible for post- harvest losses of water yam and white yam tubers and to employ plant extracts for their control. Six microorganisms comprising two bacteria, Erwinia carotovora and Pseudomonas aeruginosa and four fungi, Aspergillus niger, Aspergillus flavus, Rhizopus stolonifera, Penicillium marneffei, were isolated from three varieties (Azawele wele, kor and banada) of rotten Dioscorea alata (water yam). Nine microorganisms, comprising of four bacteria, Erwinia carotovora, Pseudomonas aeruginosa, Serratia marcescens and Klebsiella oxytoca; and five fungi, Rhizopus stolonifera, Aspergillus niger, Aspergillus flavus , Fusarium oxysporum and Penicillium marneffei, were isolated from four varieties of Dioscorea rotundata (Gbongu, Ogoja, Amula, Hembamkwase) from five Local Government Areas of Benue State (Vandeikya, Ukum, Katsina Ala, Guma and Logo). Pathogenicity test on the isolates confirmed them to be the cause of rot. Extracts of ten plants (Passiflora edulis, Daniella oliveri, Ceiba pentandra, Jatropha tanjorensis, Azadrichta indica, Carica papaya, Moringa oleifera, Mangifera indica, Terminalia catapa and Senna alata) singly and synergistically were incorporated in media for inhibition test. Single plant extract of two plants, Terminalia catapa and Passiflora edulis, inhibited completely the growth of three organisms. Terminalia catapa at 100% and 10^-1 showed complete inhibition (a) of Erwinia carotovora and Passiflora edulis at undiluted (100%) concentration completely inhibited Rhizopus stolonifera and Penicillium marneffei. Synergistic plant extracts recorded better inhibition; there was complete inhibition of all the four bacteria isolates at 2mL extract incorporation; 10mL extract incorporation in media recorded complete inhibition of three out of the five fungi isolates (Rhizopus stolonifera, Fusarium oxysporum and Penicillium marneffei and high inhibition (b) of the other two (Aspergillus niger and Aspergilus flavus), respectively. Heat employed extractions recorded less inhibition.

APHLIS Poster Series

by Tanya Stathers (APHLIS) - T.E.Stathers(at)greenwich.ac.uk

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