Research Projects

Research Topics - Egerton University

Sorghum Project

Climate Smart approaches for promotion and adoption of Sorghum for Arid and Semi-Arid Areas (ASALs) of Kenya

Mentor: Prof. Erick Cheruiyot, Ph.D; Associate Professor of Crop Physiology.

Sorghum (Sorghum bicolor), also called millet, is an indigenous cereal of Africa. It benefits from an ability to tolerate drought, soil toxicities and temperature extremes more effectively than other cereals. In terms of nutritive value, cost and availability, sorghum grain is probably the next alternative to maize in poultry feed (Etuk et al. 2012). Due to climate change and pests resulting from maize monoculture, there is a need of diversification of crop rotation and a drive for researchers to look for alternative grains for animal nutrition (Puntigam et al. 2021). The dried leaves and stems from useful roughage for cattle and horses while the well matured plant can be used as green fodder or silage. It is however, unsafe to feed the green plants to the young, since they contain dhurrin, a cyanogenic glycoside which on hydrolysis yields hydrogen cyanide (HCN) (Etuk et al. 2012). Grain fermentation may increase the nutritional value of feed and decrease dhurrin toxicity. In this context, Integration of early harvested and fermented sorghum grain in animal diets might be an interesting strategy for the substitution of maize (Puntigam et al. 2021). Notably, to relieve cold stress, sorghum plants develop a series of physiological and biochemical changes and sophisticated molecular regulatory mechanisms (Zhang 2019). The biomembrane is the barrier that protects cells from injury as well as the primary place for sensing cold signals. Chilling tolerance is closely related to the composition, structure, and metabolic process of membrane lipids. We therefore seek to understand the mechanism of cold tolerance which is proposed to be associated with lipid composition in sorghum genotypes.

Research Questions

1. What is the effect of temperature on dhurrin/ prussic acid levels in sorghum genotypes targeted for animal feed?
2. What is the salt tolerance of sorghum genotypes that are targeted for use in ASALs?
3. What is the lipid synthesis responsible for reproductive cold tolerance in sorghum?
4. Can fermentation improve the sorghum for animal feed?

Students will choose any questions and work with mentors to develop a hypothesis and RP. This research will have an impact on animal food production.

Indigenous Vegetable Project

A focus on Cassava

Led by: Prof. R. M. S Mulwa Ph.D, prof of of Horticulture

Cassava (Manihot esculenta Crantz) is an essential crop in sub-Saharan Africa occupying a double-edged position as food security and income generation crop (Alamu et al. 2019a). Amongst the vegetables consumed in western and coastal Kenya are cassava leaves. Leafy vegetables have been reported to be significant sources of antioxidants and dietary fiber. Cassava foliage meal has a relatively high vitamin A level (up to 56000 IU) (Alamu et al. 2021). In Kenya, cassava comes in two forms, the bitter and sweet types. These two classes bring about issues of food safety as the bitter cassava varieties contain high levels of cyanide and may be unsafe. In a previous effort, 27 sweet cassava varieties were collected from western Kenya and characterized for root yield and dry matter content, with a focus on Nakuro County. As farmers have expressed the desire to utilize the leaves as vegetables, we propose to conduct analysis of antinutritive compounds (tannins and phytates) and cyanide levels in these varieties to assure on food safety and nutrition.

Research Questions

1. What is the total level of anti-nutritive metabolite (phytates and tannins) in the leaves of varieties of sweet cassava collected and grown in Nakuru County?
2. What are the levels of cyanide in fresh and solar dried leaves?

This study will increase our knowledge on the anti-nutritive metabolites present in the cassava leaves with a view to establish which varieties safe for consumption.

Rhizobium Project

Nitrogen fixation in Lablab

Led by: Dr.  Nancy W. Mungai, Ph.D, Professor of  Soil Science

Multi-purpose legume species such as lablab (Dolichos purpureus (L.) Sweet) have been under-utilized yet have the potential to overcome climate challenges (Nord, et al. 2020). Lablab has a high genetic diversity and is highly drought resistant, with promising nutritional qualities (Nord 2020, Minde et al. 2021). Africa is thought to be one of lablab’s centers of origin, however, seed stocks among farmers are dwindling thus reducing farm biodiversity and leading to potential extinction in agroecosystems. The declining system diversity is one of the reasons for legumes not being optimally used in most cropping systems. Knowledge is especially lacking on the performance of this crop by genotype, management, and environment (Nord 2020). Nitrogen (N) fixation by legume-rhizobium symbiosis is important to agricultural productivity, is of great economic interest, and could save lablab from possible extinction in Kenya.

Research Questions

1. What is the diversity of the rhizobia found on four distinctive lablab accessions, defined as Mwingi-3, 10706R1, 12000 and 12187R3 by Kimani et al. (2012).
   

Biochemical and molecular methods will be used in these studies. This research will promote attention to lablab and the role of agroecosystems in maintaining genetic diversity of plants and their vital symbionts.

Finger Millet Project

Analysis of multi-environment adaptation and its effect on nutrient profiles and blending with legumes of diverse finger millet genotypes (Eleusine coracana L. Gaertn).

Led by: Prof. Paul K. Kimurto, PhD: Associate Professor of Crop Physiology

Finger millet (FM) is a staple cereal grain in some parts of the world with low income population (Ramashia et al. 2019). It is one of the millets which form traditional staple foods of the dryland regions of the world, providing necessary protein, fatty acids, minerals, vitamins, and dietary fiber (Tharifkhan 2021). In terms of nutritional composition, the crop ranks higher than other cereal grains, though the grain is widely underutilized (Ramashia et al. 2019). The millet crops commonly synthesize a secondary metabolite to protect themselves against adverse conditions (i.e., anti-nutritional factors), and the existence of these factors in millets might reduce the accessibility of the nutrients in humans. Utilization of the grain therefore involves traditional and other processing methods such as soaking, malting, cooking, fermentation, popping and radiation. These processes improve the dietetic and sensory properties of FM and assist in the reduction of anti-nutritional and inhibitory activities of phenols, phytic acids and tannins. However, there is little research on FM as compared to conventional cereals, leaving gaps regarding the cultivation methods, nutritional composition, health benefits and valorization with a view to commercialization of FM grains.

Research Questions

1. What is the phenotypic diversity of selected finger millet genotypes and its stability across varied environments? 
2. What is the effect of soil fertility and environment conditions on the nutrient profiles of the test genotypes?
3. What impacts does compositing malted finger millet flour with related dryland legumes have on value added food like baby weaning food formulations?
   

Value addition through compositing malted finger millet flour with dryland legumes could improve nutrient content of food, thus contributing to improving nutritional status of children in Kenya.

Endophytes Project

Diversity of endophytes in Kenyan forgotten food crops.

Led by: Joseph Juma Mafurah Ph.D, Lecturer,Crop Protection

Endophytes are emerging as integral components of plant microbiomes. They are non-disease causing microbes such as bacteria and fungi that live within healthy, living tissues of plants (reference). Their intimate association and possible coevolution with their plant partners have resulted in an array of benefits ranging from enhanced growth and biomass accumulation, tolerance to abiotic and biotic stresses and in nutrient acquisition (Chitnis et al. 2020). Some play pivotal roles in plant development and plant responses to pathogens, whereas others produce useful and/or interesting secondary metabolites (Burragoni and Jeon 2021). Appreciation of their abilities to affect plant phenotypes and produce useful compounds via genetic and molecular interactions has paved the way for these abilities to be exploited for health and welfare of plants, humans and ecosystems, but few of the benefits associated with endophytes have been translated into real-world agricultural applications. There is a strong need to search for novel endophyte strains with as many desirable characters for enhancing the crop yield. Novel endophytes can be screened for desirable traits from plants growing under extreme environment (Yadav and Yadav 2017).  This project will provide a platform for collecting different plant materials for finger millet and lablab bean in all major growing agroecological zones in Kenya, with an aim to ultimately increase yield and stress tolerance of those traditional crops.

Research Questions

• What is the diversity of endophytes of lablab and finger millet from different ecological zones
• What endophytes are associated with high-performing lablab and FM plants?

Enhanced discovery and productivity of endophytes of crops will help reduce our dependency on chemical fertilizers, pesticides and fungicides and promote integrated pest management (Yadav and Yadav 2017).

University of Nairobi Projects

Aflatoxins Project

Mentor: Sheila Okoth, PhD - University of Nairobi.

Infection of numerous agronomical important crops especially corn, peanuts and other cereals, by various strains of the fungi Aspergillus flavus and A paraciticus may result in production and accumulation of mycotoxins. The most prevalent mycotoxin associated with grains is Aflatoxins. The reputation of Aflatoxins as a potent poison may explain why it has been adopted for use in bioterrorism (Bennett and Klich 2003). Aflatoxicosis is the poisoning that results from ingestion of aflatoxins. Severe intoxication results in direct liver damage and subsequent illness and death. Aflatoxins are also carcinogenic, mutagenic and hepatotoxic therefore a threat to food safety and detrimental to food quality.

Students may choose any of the four possible research areas.

• "What are the different strains of Aspergillus species in finger millet (Eleusine coracana) in the different Agro-ecological zones in Kenya?" Kenya has four ecological zones, Central, Rift Valley, Coast and Western. The student will use microbiological and molecular techniques to answer the question.
• What is the difference in the Aflatoxin content of sorghum from the different ecological zones in Kenya? The samples will be collected in advance before the students arrive. They will use ELISA technique to do the studies.
• Metabolomics approaches for analysis of the differences in Aspergillus species in finger millet (Eleusine coracana) in the four different Agro-ecological zones in Kenya; Central, Rift Valley, Coast and Western?
• Metabolomics approaches for analysis of the Aflatoxin content of sorghum in the four different Agro-ecological zones in Kenya; Central, Rift Valley, Coast and Western Kenyazones.

Field trip: to the any two of the ecological zones (at least 4 days, 2 per site and two nights)

Fusarium sp and Fumonisin Project

 Mentor: TBA and Ouko Abigael (Submitted PhD dissertation) University of Nairobi.

 Fusarium ear rot (FER) and Aspergillus ear rot (AER) are important diseases of maize in Africa as they reduce both grain yield and quality. The diseases are caused by the fungal pathogens Fusarium verticillioides (Sacc.) Nirenberg and Aspergillus flavus Link:Fr., respectively. These fungi produce toxic secondary metabolites in maize grain, the mycotoxins, which pose a serious threat to human and animal health. Fumonisins, produced by F. verticillioides , have been associated with oesophageal cancer of human adults in South Africa, Italy, Iran and China (Franceshi et al.1990 ; Rheeder et al.1992; Shephard et al.2000; et al;2001 ) and neural tube defects in infants (Hendricks 1999 ;Missmer et al. 2006).

Students may choose any of these research areas. Two students may be involved, one working with Makuaeni (hot spot for aflatoxicosis) and the other student with Nandi  (major maize farming area in Kenya) samples.

• What is the Fusarium species causing causing ear rot of maize in Makueni and Nandi County? The students will identify the Fusariem species and establish their toxigenicity using molecular markers.
• What is the Fungal load? Students will quantify fungal load in kernel using Quantitative PCR (QPCR).
• How much fumonisins is in the kernel? Students will quantify fumonisins in kernels using the ELISA method

Field trip: to Makueni and Nandi (at least 4 days, 2 days per site and two nights).

Nematode Biocontrol Project

Mentor: Peter M. Wachira, PhD. University of Nairobi.

Due to the losses caused by nematodes on agricultural crops, their control is a major concern in crop production (Garcia et al., 2004). For decades now, their control has mainly depended on chemical nematicides (Akhtar and Malik, 2000) which are environmental hazards. Bacteria and fungi are good candidates for biological control of nematode. Nematophagous fungi, have attracted a lot of interest for their interactions with nematodes (Elshafie et al., 2006).

Research questions. Two students may participate, with one sampling soil from University farm and one working in Embu. What is the effect of land use on the occurrence of nematode-destroying fungi in the University farm with the aim of utilizing them as biological control agents against the plant root knot nematodes? Soil samples will be collected from various land use areas on the university farms and the fungi will be isolated using the baiting technique at the Mycology lab, Chiromo Campus and characterized using molecular techniques of (QPCR).

Field trip: To Embu. This will be two nights and 3 days).

Indigenous Vegetable Project

Mentor: Judith Agot Odhiambo Ph. D. University of Nairobi

Green leafy vegetables such as cowpea, are a very important food group in diets of individuals because of their high nutritional value (Faber et al., 2007; Muchoki, 2007; USDA, 2008). They are not only rich in nutrients, but also nutraceuticals and antioxidants such as alpha tocopherol, lycopenes, flavonoids and anticancer agents (Shetty et al., 2013). Recommendations have been made to dry and preserve leafy vegetables as a way of ensuring continued supply of food and micronutrients to communities and groups at risk of malnutrition or food insecurity (Kiremire et al., 2010).

Research Question: Two students may participate, one working on three vegetables species, Amaranthus hybridus, Cleome gynandra, Vigna unguiculate,a and the other working on Curcubuta spp , Solanum nigrum and Corchorus spp.

What is the effect of drying the vegetables on nutritional content of the vegetables? Students will use metabolomics approaches including HL-MS analysis to compare the nutritional content between the dried and fresh vegetables. The students will use metabolomics approaches such HL-MS to analysis the nutritional content of the dried and fresh vegetables.

Field trip: Western Kenya (Four days, 2 nights).