Synergistic Interactions of Soil and Vegetation in Agroforestry Systems in Mitigating Climate Change in Upper East Region, Ghana

Climate change has been a global pandemic with its adverse impacts affecting environments and livelihoods. This has been largely attributed to anthropogenic activities which generate large amounts of Green House Gases (GHGs), notably carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) among others. In the Upper East of Ghana, climate change manifests in erratic rainfalls, drought, high temperatures, high wind speeds, high intensity rainfall, windstorms, flooding, declining vegetation cover, perennial devastating bushfires etc. Practices such as burning farm residues, use of dung as fuel for cooking, excessive application of nitrogenous fertilizers, and deforestation that are prevalent in the region exacerbate the situation. Although, efforts made by governmental and none-governmental organizations to mitigate climate change through afforestation, agroforestry and promotion of less fuelwood consuming cook stoves, land management practices antagonize these efforts as more CO2 is generated than the carrying capacity of vegetation in the region. Research findings have established the role of trees and soil in carbon sequestration in mitigating climate. However, there is limited knowledge on how the vegetation and soil in agroforestry interplay in mitigation climate change. It is against this background that this review seeks to investigate how vegetation and soil in an agroforestry interact synergistically to sequester carbon and contribute to mitigating climate change in Upper East region of Ghana. In this review, it was discovered soil stored more carbon than vegetation in an agroforestry system and is much effective in mitigating climate change. It was found out that in order to make soil and vegetation in an agroforestry system interact synergistically to effectively mitigate climate change, Climate Smart Agriculture practice which integrates trees, and perennials crops effectively mitigates climate. The review concluded that tillage practices that ensure retention and storage of soil organic carbon (SOC) could be much effective in carbon sequestration in the Savannah zones and could be augmented with vegetation to synergistically mitigate climate change in the Upper East region of Ghana.

Integrated use of GIS, remote sensing and multi-criteria decision analysis to assess ecological land suitability in multi-functional forestry

The Zagros forests are a treasure of valuable oak forests, but they have been severely degraded from long-term misuse. Geographic information systems （GIS） and multi-criteria decision analysis （MCDA） have been increasingly used to improve the management of vulnerable ecosystems to prevent further degradation and increase the sustainability of land use. This study presents a methodology to assess land suitability using remote sensing （RS） to obtain wall-to-wall data for the calculations, GIS to analyze the data, and MCDA to rank alternative land uses. The criteria and subcriteria affecting the suitability of land for different uses were identified and weighted using an analytic hierarchy process. Variables used as subcriteria were assessed using satellite data and other sources of information such as existing maps and field surveys. Numerical values for the subcriteria were classified, and each class was given a priority rating according to expert judgments. Based on the ratings and weights of the subcriteria, a priority map was created for each land use using the weighted linear combination method. The priority maps for different land uses were overlaid to obtain a preliminary land use map, which often indicated several simultaneous land uses for the same location. The preliminary map was further edited by removing unrealistic, mutually exclusive land-use combinations. The study tested and demonstrated the potential of integrating RS, G1S and MCDA techniques for solving complicated land allocation problems in forested regions using a scientifically sound and practical approach for efficient and sustainable allocation of forestland for different uses.

The Use of Drones in Forestry

Recently, drones have found applicability in a variety of study fields, one of these being forestry, where an increasing interest is given to this segment of technology, especially due to the high-resolution data that can be collected flexibly in a short time and at a relatively low price. Also, drones have an important role in filling the gaps of common data collected using manned aircraft or satellite remote sensing, while having many advantages both in research and in various practical applications particularly in forestry as well as in land use in general. This paper aims to briefly describe the different approaches of applications of UAVs （Unmanned Aircraft Vehicles） in forestry, such as forest mapping, forest management planning, canopy height model creation or mapping forest gaps. These approaches have great potential in the near future applications and their quick implementation in a variety of situations is desirable for the sustainable management of forests.

Effects of phosphorous fertilizer on seedlings growth and nodulation capabilities of some popular agroforestry tree species of Bangladesh

An experiment was conducted to assess the effect of Phosphorous （P） fertilizer （i.e. TSP or triple super phosphate @ 80 kg/hm^2） on seedling growth and nodulation capabilities of three potentially important agroforestry tree species （Acacia auriculiformis, Albizia lebbeck and Albizia procera） of Bangladesh. The study was conducted in nursery beds with six-month-old polybag seedlings ofA. auriculiformis, A. lebbeck and A. procera. The effects of P fertilizer on seedling growth and nodulation were compared with that of the seedlings grown in control （i.e. unfertilized soil）. The observations revealed that the seedling growth was enhanced significantly with the application of P fertilizer. The growth was found more pronounced in A. auriculiformis, whereas it was not apparent and shows depressed growth in case ofA. lebbeck. The study also suggests that the nodulation in terms of nodule number and size was also increased significantly with the application of P fertilizer.

Analysis of existing agroforestry practices in Madhupur Sal forest: an assessment based on ecological and economic perspectives

A study was conducted in Madhupur sal forest of Tangail, Bangladesh to identify the suitable agroforestry practices of the area. Considering the ecological aspects of different agroforestry practices 10 sample plots （10 m× 10 m） from each land uses were taken, including natural forest to get a comparative scenario. The study showed that among the different agroforestry practices, Margalef and Shannon- Weiner index values are the maximum for pineapple agroforestry and lower for banana agroforestry, and Evenness index value is the maximum for lemon agroforestry. Determination of tree biomass in different land uses revealed that it is highest （3 078.6 kg/100 m^2） in natural forest followed by pineapple agroforestry, lemon agroforestry and banana agroforestry. Soil pH, moisture content, organic matter, organic carbon, phosphorus and total nitrogen showed statistically significant variation while bulk density, particle density, sulphur and potassium did not show any statistically significant variation among the land uses. Soil fertility status showed that pineapple agroforestry is more fertile than rest of other land uses. The Net Present Value （NPV） indicated that banana agroforestry is financially more profitable than other two systems, while the Benefit- Cost ratio （BCR） is higher in pineapple agroforestry （4.21 in participatory agroforestry and 3.35 in privately managed land）. Even though banana agroforestry gives higher NPV, capital required for this practice is much higher. The findings suggest that pineapple agroforestry has a tendency towards becoming ecologically and economically more sound than other two practices as it has better ecological attributes and required comparatively low investment.

Dissemination paradox:how contextual realities influence smallholder farmers'modifications of agroforestry technologies in Uganda's Mt.Elgon region

This study was intended to understand how smallholder farmers’modifications improved agroforestry technologies’usability in Uganda’s Mt.Elgon region.We used a case study approach to understand how smallholder farmers’contextual realities informed their modifications and enhanced the usability of agroforestry technologies.Data was collected over four months of frequent and regular interaction with the cases using formal and informal methods that included in-depth interviews,conversations,discussions,and direct observations.Emerging themes and patterns were identified from the comprehensively reduced data.In addition,respondents’direct quotes were used to emphasize the reasons for the modifications.The findings showed that smallholder farmers modified the recommended technologies to suit their biophysical and socio-economic realities.Differences and similarities in modifications existed among cases across the agroforestry technologies.The modifications were mainly done to diversify tree uses,optimize space utilization,and minimize production costs for farming households.These findings imply a need to critically examine the smallholder farmers’modifications to make agroforestry technologies applicable and compliant to their contexts.This will inform the re-invention of technologies that will quickly diffuse into the community for broader impact.Findings also emphasize the need to rethink the linear model of technology transfer mainly applied in agroforestry technology development and dissemination because it offers limited space for the much-needed feedback from smallholder farmers.

Open Source GIS Software Options for Forestry Education in Papua New Guinea

Although open source softwares (OSS) for GIS and Remote Sensing are rapidly expanding and improving in the global context, there has been uncertainty at higher education institutions in developing countries, such as the department of forestry (Dfo) at Unitech, Papua New Guinea (PNG), regarding appropriate GIS softwares and hardware to acquire and use for teaching and research purposes. The paper briefly describes the characteristics of some mature OSS and discusses their main capabilities, advantages and disadvantages. Their adoption in the Dfo curricula may be advantageous in the long term, considering issues of learning curve steepness, versatility, affordability, effectiveness, and documentation available on them.

Comparative Study of Cooling under Shades of Some Forestry Tree Species with Respect to Ambient Temperatures

Trees create microclimate under their crowns in comparison to the outside ambient atmospheric temperature. Sun is the pivotal source of radiant energy reaching the earth atmosphere of which heat is more important than light. The radiant energy reaches the ground without any barricade whereas the tree crown impedes it in reaching the earth’s surface. During the day, when insolation impinges on tree crown, a portion of it is reflected back to the space, other portion is absorbed by the canopy increasing the temperature of leaves and the remaining part reaches the ground penetrating through the crown. Thus, a significant coolness is experienced under the shade of trees in comparison to open sunshine, with qualitative variations. The cooling produced by trees under their shades varies with species to species due to variation in several anatomical, structural and physiological attributes of the species. Climate is changing more rapidly prominently due to human activities especially indiscriminate felling of trees and it is feared that it will create problems on availability of energy, water and food security. Economic value takes over ecological benefits in selection of species in plantation programmes and this might have been due to the lack of scientific data about varying effectiveness of ecological services bestowed by different species. In the present study, an endeavor has been made to understand as to how a tree is integrated to the effects on atmosphere and responses to changing conditions with respect to differential cooling produced by five selected forestry tree species belonging to different categories. Analysis of data has come out with gradation of the sample species in respect to their cooling effect in the atmosphere in terms of yearly, quarterly, monthly and diurnal basis.

Agroforestry for Climate Change Adaptation,Resilience Enhancement and Vulnerability Attenuation in Smallholder Farming Systems in Cameroon

The adverse impacts of climate variability and change are felt mostly by smallholder farmers and smallholder farming systems where rain-fed agriculture is predominant.Continuous dependence on rain-fed agriculture has led to declining crop productivity and crop failure in most cases as weather patterns shift which is very problematic for crop growth.Agroforestry which is one of the climate-smart,environmentally benign and agroecological practices has been found to mitigate climate change adversities while fostering adaptation,enhancing resilience and attenuating vulnerability especially in smallholder farming systems.However,in Cameroon,limited empirical research has been done to ascertain the role played by agroforestry in climate change adaptation,resilience enhancement and vulnerability attenuation.This paper which is based on an in-depth review of literature was undertaken to uncover what has been done so far in terms of empirical studies tackling the role played by agroforestry in climate change adaptation,resilience and vulnerability attenuation in Cameroon.It was found that most of the empirical studies have been carried out in one agroecological zone-the western highlands of Cameroon,showing that smallholder farmers adopt different agroforestry practices in the face of climate change with the most common being home gardens with livestock,home gardens without livestock,scattered trees on croplands,improved fallows,live fences/hedges and windbreaks,coffee-based agroforestry,cocoa-based agroforestry,apiculture-based agroforestry,fodder banks,and plantation crop-based agroforestry practices.These agroforestry practices provide a plethora of ecosystem services categorized into provisioning,supporting,regulating and cultural which play an important role towards fostering climate change adaptation,enhancing resilience and attenuating vulnerability in smallholder farming systems.From the findings uncovered by this study,it is imperative for more empirical studies to be carried out in the other four agroecological zones of Cameroon where there is a paucity of information regarding the role played by agroforestry towards fostering climate change adaptation,enhancing resilience and attenuating vulnerability in smallholder farming systems.

Annual growth of Fagus orientalis is limited by spring drought conditions in Iran’s Golestan Province

Due to the lack of a uniform and accurate defi-nition of‘drought’,several indicators have been introduced based on different variables and methods,and the efficiency of each of these is determined according to their relationship with drought.The relationship between two drought indices,SPI(standardized precipitation index)and SPEI(standard-ized precipitation-evapotranspiration index)in different sea-sons was investigated using annual rings of 15 tree samples to determine the effect of drought on the growth of oriental beech(Fagus orientalis Lipsky)in the Hyrcanian forests of northern Iran.The different evapotranspiration calcula-tion methods were evaluated on SPEI efficiency based on Hargreaves-Samani,Thornthwaite,and Penman-Monteith methods using the step-by-step M5 decision tree regression method.The results show that SPEI based on the Penman-Monteith in a three-month time scale(spring)had similar temporal changes and a better relationship with annual tree rings(R^(2)=0.81)at a 0.05 significant level.Abrupt change and a decreasing trend in the time series of annual tree rings are similar to the variation in the SPEI based on the Penman-Monteith method.Factors affecting evapotranspiration,temperature,wind speed,and sunshine hours(used in the Penman-Monteith method),increased but precipitation decreased.Using non-linear modeling methods,SPEI based on Penman-Monteith best illustrated climate changes affecting tree growth.

The storage and utilization of carbohydrates in response to elevation mediated by tree organs in subtropical evergreen broad-leaved forests

Global climate change can affect tree growth and carbon sink function by influencing plant carbohydrate synthesis and utilization,while elevation can be used as an ideal setting under natural conditions to simulate climate change effects.The effect of elevation on tree growth may depend on organ type.However,the allocation patterns of nonstructural and structural carbohydrates(NSCs and SCs,respectively)in different tree organs and their response to elevation remain unclear.We selected four dominant tree species,Schima superba,Castanopsis eyrei,Castanopsis fargesii and Michelia maudiae,along an elevation gradient from 609 to 1,207 m in subtropical evergreen broad-leaved forests and analyzed leaf,trunk,and fine root NSCs,carbon(C),nitrogen(N)and phosphorus(P)concentrations and the relative abundance of SCs.Leaf NSCs increased initially and then decreased,and trunk NSCs increased with increasing elevation.However,root NSCs decreased with increasing elevation.The relative abundance of SCs in leaves and trunks decreased,while the relative abundance of root SCs increased with increasing elevation.No significant correlations between SCs and NSCs in leaves were detected,while there were negative correlations between SCs and NSCs in trunks,roots,and all organs.Hierarchical partitioning analysis indicated that plant C/N and C/P were the main predictors of changes in SCs and NSCs.Our results suggest that tree organs have divergent responses to elevation and that increasing elevation will inhibit the aboveground part growth and enhance the root growth of trees.A tradeoff between the C distribution used for growth and storage was confirmed along the elevation gradient,which is mainly manifested in the"sink"organs of NSCs.Our results provide insight into tree growth in the context of global climate change scenarios in subtropical forest ecosystems.

Relating estimates of wood properties of birch to stem form, age and species

Birch has long suffered from a lack of active forest management,leading many researchers to use mate-rial without a detailed management history.Data collected from three birch(Betula pendula Roth,B.pubescens Ehrh.)sites in southern Sweden were analyzed using regression analysis to detect any trends or differences in wood proper-ties that could be explained by stand history,tree age and stem form.All sites were genetics trials established in the same way.Estimates of acoustic velocity(AV)from non-destructive testing(NDT)and predicted AV had a higher correlation if data was pooled across sites and other stem form factors were considered.A subsample of stems had radial profiles of X-ray wood density and ring width by year created,and wood density was related to ring number from the pith and ring width.It seemed likely that wood density was negatively related to ring width for both birch species.Linear models had slight improvements if site and species were included,but only the youngest site with trees at age 15 had both birch species.This paper indicated that NDT values need to be considered separately,and any predictive models will likely be improved if they are specific to the site and birch species measured.

Population genetic insights into the conservation of common walnut(Juglans regia)in Central Asia

The common walnut(Juglans regia)is one of the most economically important nut trees cultivated worldwide.Despite its importance,no comprehensive evaluation of walnut tree population genetics has been undertaken across the range where it originated,Central Asia.In this study,we investigated the genetic diversity and population structure of 1082 individuals from 46 populations across Central Asia.We found moderate genetic diversity of J.regia across Central Asia,with 46 populations clustered into three groups with a weak relationship between genetic and geographic distance.Our findings reveal that the western Himalaya might be the core region of common walnut genetic diversity in Central Asia and that,except for two populations in Gongliu Wild Walnut Valley,humans might have introduced walnut populations to Xinjiang,China.The observed distribution of the genetic landscape has probably been affected by historical climate fluctuation,breeding system,and prolonged anthropogenic activity.We propose the conservation of the core genetic diversity resources in the western Himalaya and pay special attention to populations from Gongliu in Xinjiang.These findings enhance our understanding of the genetic variation throughout the distribution range of J.regia in Central Asia,which will provide a key prerequisite for evidence-based conservation and management.

Carbon stock estimation in halophytic wooded savannas of Uruguay:An ecosystem approach

Savannas constitute a mixture of trees and shrub patches with a more continuous herbaceous understory.The contribution of this biome to the soil organic carbon(SOC)and above-ground biomass(AGB)carbon(C)stock globally is significant.However,they are frequently subjected to land use changes,promoting increases in CO_(2) emissions.In Uruguay,subtropical wooded savannas cover around 100,000 ha,of which approximately 28%is circumscribed to sodic soils(i.e.,subtropical halophytic wooded savannas).Nevertheless,there is little background about the contribution of each ecosystem component to the C stock as well as site-specific allometric equations.The study was conducted in 5 ha of subtropical halophytic wooded savannas of the national protected area Esteros y Algarrobales del Rio Uruguay.This work aimed to estimate the contribution of the main ecosystem components(e.g.,soil,trees,shrubs,and herbaceous plants)to the C stock.Site-specific allometric equations for the most frequent tree species and shrub genus were fitted based on basal diameter(BD)and total height(H).The fitted equations accounted for between 77%and 98%of the aerial biomass variance of Netuma affinis and Vachellia caven.For shrubs(Baccharis sp.),the adjusted equation accounted for 86%of total aerial biomass.C stock for the entire system was 116.71±11.07 Mg·ha^(-1),of which 90.7%was allocated in the soil,8.3%in the trees,0.8%in the herbaceous plants,and 0.2%in the shrubs.These results highlight the importance of subtropical halophytic wooded savannas as C sinks and their relevance in the mitigation of global warming under a climate change scenario.

Genotypic effects on accelerated propagation of oil palm breeding materials selected(Elaeis guineensis jacq.)using somatic embryogenesis

Vegetable oil production from oil palm(Elaeis guineensis Jacq.)is an important industry due to the rising demand every year.The somatic embryogenesis culture can propagate oil palm duplicate as parent plant,which can be selected as breeding material to produce new planting germplasm with high production or disease resistance.This study aims to evaluate the genotypic effect of somatic embryogenesis,while immature leaflets were employed as explants.The culture used embryo induction medium based on Murashige and Skoog(MS)modifications that contained 5 mg/L Naphthalene Acetic acid(NAA)and 0.5 mg/L Benzyl Amino Purine(BAP).The genotypic effect was statistically significant in the percentage of callus induction,producing somatic embryos,and germination embryos.In this study,we successfully cloned thirteen oil palm genotypes(GE-02,GE-03,GE-06,GE-07,GE-09,GE-23,GE-24,GE-27,GE-28,GE-32,GE-33,GE-34,and GE-35),with the highest number of somatic embryos formed on GE-27 with a percentage of 70.1%.The cloning was successful in accelerating the propagation of oil palm for materials breeding programs to create new varieties with high production and disease resistance.It is necessary to observation the performance of these clones in the field in terms of mantle flower appearance.

Combined Application of Biostimulants and EDTA Improved Wheat Productivity under Cadmium Stress

Wheat(Triticum aestivum L.)exhibits a greater capacity for cadmium(Cd)absorption compared to other cereal crops,leading to elevated daily Cd intake,and posing a significant threat to public health.For the mitigation of Cd stress in sustainable and environmentally friendly way,a pot study was designed by using exogenous application of various biostimulants,i.e.,Nigella sativa and Ocimum sanctum extracts:0%,10%,and 20%in combination with the chelating agent ethylenediaminetetraacetic acid(EDTA)using 0 and 5 mg kg^(-1) under various levels of Cd stress(i.e.,0,5,10,and 15 mg kg^(-1) soil).Results revealed that Cd stress significantly reduced the seed emergence,growth,root,and allometric characters and yield-related parameters of wheat crops.The most observable reduc-tion was documented in wheat plants exposed to a higher Cd concentration(15 mg kg^(-1)),followed by the lower Cd level(control).The combined application of bio-stimulants and EDTA minimized the negative impacts of Cd stress.The highest increase in seedling emergence(5.44%),leaf area(50.60%),number of tillers(31.02%),grain yield per plant(24.28%),biological yield(13.97%),and decrease in Cd levels in grains(40%)was noticed where 20%foliar application of N.sativa and 10%of O.sanctum biostimulants were done using 5 mg kg^(-1) of soil-applied EDTA.This intervention demonstrated a notable reduction in Cd-induced negative effects,highlighting the potential of these substances in promoting sustainable wheat cultivation in contaminated environments.Moreover,it is an eco-friendly and approachable method at thefield level able to ensure food safety.

The Impacts and Causes of Land Fragmentation on Farm Productivity: Case Review of East African Countries

This report provides an overall assessment of land fragmentation problems in East Africa. Many parts of East Africa have become highly fragmented, putting development systems and activities in these areas at risk of complete collapse. Land fragmentation occurs when land gets converted for agriculture, industrialization, or urbanization, invaded by non-local plants, or enclosed for individual use and by subdividing farmlands into subsequent smaller units called parcels with varying average farm sizes. Fragmentation results from inappropriate agricultural development processes and ineffective land use planning that fails to recognize how farmland is used, and the importance of its interconnected areas. Insecurity of tenure and resource rights are key factors in making this possible. Land fragmentation is one of the key reasons why the ability of most resources in East Africa becomes scarcer, and those remaining become “privatized” by more powerful community members—keen to maintain their access to them. Such individualistic attitudes are new and disadvantage the poorest even further by affecting the traditional customary safety nets and agricultural outputs. Neither the government nor customary governance systems effectively protect resource access for the poorest. This review summary report identifies the key causes, measures, and implications, government interventions, and the common remedies to land fragmentation problems in the East African Countries of Kenya, Uganda, Rwanda, and Tanzania including neighboring Ethiopia, and the Sudan. The findings indicated from 2005 to 2015, the population kept increasing for all the named countries in East Africa with Rwanda and Uganda having a substantial increase in population density. The study review further explores the trend in the performance of agriculture by average farm sizes within the intervals of five years by highlighting their strong linkages and found that the average farm size has declined drastically, especially for Kenya. This can only mean that small farms kept becoming smaller and smaller and that there were more small-scale farmers. The results further depicted that the major and commonly cultivated food crops among the East African countries include maize, sorghum, rice, cassava, sweet potatoes, bananas, Irish potatoes, beans, peas, etc., with maize yields (Mt/ha) in 2003 for Uganda being the highest (1.79 Mt/ha) and the lowest in Rwanda (0.77 Mt/ha) respectively. Therefore, from the review results, recommendations are being made as to how the negative impacts of land fragmentation on agricultural productivity can be reduced or mitigated. One way is by community sensitization and awareness about the importance of land consolidation and its proposition on farm productivity.

Assessment of Contamination Degree of Oil Residues on a Former Agricultural Site

In this study,our goal is to identify the land surface that has been polluted/degraded by petroleum products or other identified causes through laboratory analysis,to assess the depth of current contamination and to identify the specific causes of contamination.The level of contamination will be assessed by analyzing a total of 90 soil samples,both within the first 30 cm depth and within the 30-60 cm interval.The potential impact of the petroleum activities and their effects on the environment and agricultural development in the area will be evaluated by studying the distribution of the chemical elements analyzed,particularly total petroleum hydrocarbons(TPH).In addition,a thematic map was created using MapSys 10.0 software based on their distribution,indicating the polluted areas using color codes and values.This analysis and mapping revealed that 7,473 square meters of the site were severely contaminated at 30 cm,representing approximately 25% of the site.

Integration of 1H-NMR-Based Metabolomics Approach with Traditional Chinese Pulse Diagnosis to Evaluate the Qi-Enhancing Activity of Herbal Tea

Human metabolism is intricately linked to an individual’s health status. Regardless of living habits, it will be reflected in the metabolic characteristics of urine. The utilization of the 1H NMR-based metabolomics method has enabled examine the metabolomic changes in urine under various physiology conditions, providing valuable insights into metabolites. In this particular study, volunteers were divided into two groups based on the strength of their spleen pulses, using the pulse diagnosis method employed in traditional Chinese medicine. Subsequently, their urine samples were analyzed, revealing notable variances in urea, creatinine, citric acid, succinic acid, trimethylamine-N-oxide (TMAO), alanine, hippuric acid, and glycine between the two groups. Interestingly, individuals with weak spleen pulses showed significant improvements after consuming herbal tea. Furthermore, we conducted LC-MS analysis on herbal tea and performed adenosine triphosphate (ATP) activity tests on the C2C12 mouse skeletal muscle cell line. The results indicated that within a reasonable concentration range, exposure to herbal tea led to an increase in the mitochondrial ATP production capacity of C2C12 cells. These findings shed light on the relationship between traditional Chinese medicine pulse diagnosis and urine metabolites, highlighting their potential as non-invasive and straightforward health assessment indicators. They can aid in the preliminary determination of necessary dietary and lifestyle changes to enhance overall bodily health.

Embryonic and Larval Development of Reciprocal Crosses between Clarias gariepinus (Burchell, 1822) and Clarias jaensis (Boulenger, 1909) in West Cameroon

Establishing intraspecific breeding and hybridization programs and determining genetic variability are two important issues for aquaculture. However, interspecific hybridization to improve growth and feeding efficiency is limited. For this purpose, the embryonic and larval development of reciprocal crosses of Clarias gariepinus (Burchell, 1822) and Clarias jaensis (Boulenger, 1909) were studied under laboratory conditions. The fertilization rate varied from 63.33% to 92%, while the hatching rate ranged from 55.68% to 76% with the highest value in hybrids ♀Cg × ♂Cj. Crosses between ♀Cj × ♂Cj, ♀Cg × ♂Cj and ♀Cj × ♂Cg had embryonic stages similar to those of the pure sib ♀Cg x ♂Cg. All crosses, however, had different timing for the various embryological stages. Hatching occurred at 32 h 15 min and 38 h for ♀Cj × ♂Cj and ♀Cj × ♂Cg, and 23 h and 23 h 30 min, respectively, for ♀Cg × ♂Cg and ♀Cg × ♂Cj. However, both crosses produced viable larvae until the first external feeding. The external morphological features of the larvae were completely formed by the 10th day after hatching. The body forms of the crosses at this time were indistinguishable from the pure sib. This study thus laid the groundwork for further comparative studies on hybrid performance and characterization.