Environmental & Physical Sciences

Environmental & Physical Sciences Research Papers/Topics

Genetic diversity among commercial coffee varieties, advanced selections and museum collections in Kenya using molecular markers

Abstract Molecular markers have effectively been applied to study genetic diversity and as markers of particular traits. This study assessed the diversity of twenty four (24) coffee genotypes using 10 Random Amplified Polymorphic DNA (RAPD) primers and 2 microsatellites (M24 and Sat 235). A total of 35 polymorphic bands were generated by the RAPD primers. The bands were scored for presence (1) and absence (0) of amplified products. The data was subjected to cluster analysis using R statistic...

Isolation, characterization and identification of Diazinon degrading bacteria from the soil and gut of macrotermes

Abstract Diazinon degrading bacteria were isolated from the soil and gut of fungus cultivating termites Macrotermes michaelseni using MM7 media supplemented with pesticide as the sole source of carbon and energy. The isolates were gram negative rods the isolates from the soil were designated DS2, DS3 and DS5 while from termite gut was designated DT2. 16S rRNA gene sequence analysis showed that diazinon degrading isolate DS2 (from the soil) is closely related to Achromobacter xylosoxidan AF50...

Chemical properties associated with guts, soil and nest materials of Odontotermes and Macrotermes species from Kenya

Abstract Changes in carbon and nitrogen cycles in tropical soils affect soil functioning and ecosystem activity. Termites play important roles in carbon and nitrogen cycles, thus determination of levels of such compounds is essential. This study was aimed at determining the levels of various forms of nitrogen, carbon and pH in the guts, soil and nest materials associated with Odontotermes and Macrotermes termite species. Macro- and micro-elements such as potassium, calcium, magnesium, phosph...

Mitochondrial DNA variation of Bemisia tabaci (gennadius) (hemiptera: aleyrodidae) infesting cassava in Kenya

Abstract Bemisia tabaci is a widely distributed crop pest affecting the yield of a broad range of agricultural, fiber, vegetableand ornamental crops. It is an extremely polyphagous pest that causes direct damage and can act as a vector ofviral plant diseases. Populations of Bemisia tabaci that are morphologically indistinguishable and with differentbiological traits have been known to exist; they show differences in rates of development, host range, insecticideresistance and virus transmissi...

Effects of pea aphid secondary endosymbionts on aphid resistance and development of the aphid parasitoid Aphidius ervi: a correlative study

Abstract In order to reduce parasite-induced mortality, hosts may be involved in mutualistic interactions in which the partner contributes to resistance against the parasite. The pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae), harbours secondary bacterial endosymbionts, some of which have been reported to confer resistance against aphid parasitoids. Although this resistance often results in death of the developing parasitoid larvae, some parasitoid individuals succeed in develo...

Infestation Levels and Molecular Identifcation Based on Mitochondrial COI Barcode Region of Five Invasive Gelechiidae Pest Species in Kenya

Abstract Invasive Gelechiidae pest species, namely Tuta absoluta, Phthorimaea operculella, Aproaerema simplixella, Sitotroga cerealella, and Pectinophora gossypiella are among the major constraints hampering agricultural economy in Kenya. Infestation levels were determined on respective host crops sampled from different localities and P. operculella recorded the highest infestation of 68.00 ± 4.92% on stored potato. Aproaerema simplixella and T. absoluta accounted for 61.33 ± 5.35% and 51....

Variation in Seagrass Carbon Stocks Between Tropical Estuarine and Marine Mangrove-Fringed Creeks

Abstract Seagrass and associated blue carbon ecosystems are important carbon sinks, and hence understanding their spatial and temporal variability is vital in appreciating their potential roles in climate change mitigation and adaptation. The Indo-Pacific region has the highest seagrass biodiversity, yet little focus has been made to compare seagrass habitat extent and carbon dynamics with their temperate counterparts. The present study assessed habitat characteristics and seagrass species ...

Seagrass Loss and Sub-Surface Carbon Fate: Insights from a Long-Term Experimental Removal in Gazi Bay, Kenya

Abstract Seagrass meadows are considered as global hotspots of blue carbon stocks. However, they suffer global cover loss mainly due to anthropogenic activities. Few is known on the impact of seagrass loss on their blue carbon stocks. This study investigates the impact of seagrass removal on soil organic carbon stocks two years after initial perturbation, and the potential bioturbation activity of co-existing burrowing shrimps in Gazi Bay, Kenya. Seagrass aboveground biomass was removed for ...

Indigenous knowledge on host tree preference of the wild edible Gynanisa maja (Lepidoptera: Saturniidae) matches with the laboratory test results in western Zambia

Abstract/Overview Gynanisa maja is an edible caterpillar and contributes significantly towards household food security. The linkage between indigenous and scientific knowledge influencing G. maja forage preference is not yet clear, and therefore the study aimed at determining this linkage regarding host preferences for G.maja in western Zambia. A household survey was conducted to determine people’s perception on the most preferred host plants and in order to compare with the laboratory ...

Processed products of termites and lake flies: Improving entomophagy for food security within the Lake Victoria region

Abstract/Overview Among the factors contributing to food shortage in Africa are lack of appropriate preservation and storage facilities, tropical heat and poor road network for marketing produce. High food spoilage caused by high temperatures of the tropical areas necessitates storage for all householders. Marginal areas of Lake Victoria often suffer protein deficiency due to dependence on narrow base sources of protein, most of which get spoilt during storage. The lake region is endowed ...

An analysis of socio demographic and agronomic factors associated with adoption of improved mango varieties among small scale farmers in Alego Usonga sub-county

Abstract/Overview The adoption of improved mango in Alego Usonga was still low covering an area of 12 Ha out of 47800 Ha of the arable land constituting only 0.025 %. The objective of this study was to determine the agronomic and demographic factors that influence adoption of improved mango varieties in Alego Usonga Sub County. The study adopted a cross sectional design to interview selected mango farmers who adopted planting of improved varieties. The study population was 320 famers with...

Edible Crickets (Orthoptera) Around the World: Distribution, Nutritional Value, and Other Benefits—A Review

Abstract/Overview Edible crickets are among the praised insects that are gaining recognition as human food and livestock feed with a potential of contributing to food security and reduction of malnutrition. Globally, the sustainable use of crickets as food or feed is undermined by lack of information on the number of the edible crickets, the country where they are consumed, and the developmental stages consumed. Furthermore, lack of data on their nutritional content and the potential risk...

The effects of long-term burning regimes on savanna spider assemblages

Abstract: Fire is an important disturbance in many biomes throughout the world and plays a major role in savannas, where it affects the composition and structure of vegetation, which in turn structures faunal assemblages. Higher intensity and more frequent fires tend to simplify habitat structure, leading to a decrease in faunal abundance and diversity. Fire is often used as a tool in conservation areas, but the effects of fire, in particular long-term burning regimes, on fauna is largely un...

Reservoir sedimentation in an arid and semi-arid river basin; a case study of Kalundu dam in Kitui County, Kenya

Abstract: In Kenya, several water reservoirs located in arid and semi-arid lands (ASALs) are undergo the trouble of accumulation of sediments. Kalundu Dam in Kitui County is a typical reservoir located in ASAL that has been experiencing periodic siltation since 1950s when it was commissioned. However, the patterns of siltation within the dam including the hydrological processes influencing sedimentation processes have not been investigated in this reservoir as with other reservoirs in Kenya�...

Study of commercial banks’ responses to climate change; a case of commercial banks in Kitui County Kenya

Abstract: The world has set targets to reduce the global warming that requires every sector of the economy to take measure to mitigate climate change. Banks and other financial institutions can play a central role in achieving these targets since climate change presents financial risks that should be treated accordingly. To assess and manage these risks, banks should apply scenario analysis and adopt climate related risk disclosure recommendations. This study analysed how Commercial banks op...


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