Shannon-Weaver Diversity Index Research Articles

Influence of the hydrological regime of lake buyo on fish community of three floodplains in the Tai national park (southwestern Côte d’Ivoire)

Floodplains play an important role in the ecological functioning of the areas on which they depend. These plains are also of socio-economic interest to the local population, particularly in terms of fishing activities. The fish fauna of three Lake Buyo floodplains (Néma, Libériakôbro and Gah) was studied in relation to the lake's hydrological regime. The aim of this study was to evaluate the influence of the hydrological seasons of Lake Buyo on the structure of the fauna considered. Sampling of fish community was carried out monthly during an annual cycle using experimental fishing. The structure of the fish community was analyzed by determining taxonomic composition, taxon abundances (Ar) and the Shannon-Weaver diversity (H') and Pielou equitability (E) index. Temporal dynamics of the studied parameters were analyzed according to three hydrological seasons: flood season, high water season and recession season. Results showed that total specific richness of ichthyofauna of the studied plains was 38 species, and the richness observed at the different hydrological seasons varied significantly (p < 0.05). The Cyprinidae family was dominant in the abundances recorded at all seasons (48.34% ≤ Ar ≤ 85.5%). It should be noted that the studied ichthyofauna exhibited relatively low diversity and equitability with reference to diversity index (1.42 ≤ H' ≤ 1.46 and 0.28≤ E ≤ 0.29).

Enhancing Maize Germplasm Selection for Genebanks: A Decision Support System Combining Shannon-Weaver Diversity Index and Machine Learning

Enhancing Maize Germplasm Selection for Genebanks: A Decision Support System Combining Shannon-Weaver Diversity Index and Machine Learning

Symbiont Diversity in Imidacloprid-Resistant and Imidacloprid-Susceptible Populations of Nilaparvata lugens (Hemiptera: Delphacidae)1

Abstract Imidacloprid, a neonicotinoid insecticide, is efficacious against hemipterans, including the brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae). However, frequent use of this insecticide has resulted in the development of high levels of resistance among brown planthopper populations. Endosymbionts of insects have contributed to host physiology and evolution and play a role in resistance to chemical toxins. In this study, polymerase chain reaction–denaturing gradient gel electrophoresis was used to analyze the bacterial and yeast-like symbiont communities of imidacloprid-resistant and -susceptible brown planthopper populations. The Shannon-Weaver diversity index and the evenness index indicated no differences in the richness and the expression of overall species distribution of the symbiotic communities of resistant and susceptible populations. The similarity coefficients of 0.53 and 0.56 for bacterial and yeast-like symbionts, respectively, indicated the main types of differences among microorganisms in resistant and susceptible populations. Sequence comparison analysis indicated the bacterial species in the susceptible population were members of the Enterobacteriaceae and Moraxellaceae, and those in the resistant population were members of the Enterobacteriaceae, Oxalobacteriaceae, Rhodobacteriaceae, and Sphingomonadaceae. Differences also were found in the composition of yeast-like symbionts of the two populations; Cryptococcus luteolus, Pseudozyma aphidis, and Pseudozyma antarctica were detected in the susceptible population, and Cladosporium perangustum was detected in the resistant population.

The biodiversity and conservation assessment of Bamui beel in Bangladesh: Current status and threats

A year-long research was conducted with a novel purpose for categorizing and documenting the existing fish diversity and abundance of Bamui beel in Jamalpur district located in Northeast part of Bangladesh, within a time frame from July 2022 to June 2023. A total of 46 fish species were identified that belonged to 18 taxonomical families and 8 orders. The most abundant family was Cyprinidae (25%). Among 46 species, 37% were commonly available (CA) and 11% were abundantly available (AA) in terms of biodiversity status. According to the global conservational status, around 74% were reported as least concerned (LC) whereas 4% were nearly threatened (NT). On the other hand, in consonance with the conservational status of Bangladesh 52% were least concerned (LC) and 11% were endangered (EN). Pielou’s evenness score in Bamui beel was the highest (0.247) in pre-monsoon and the lowest (0.213) in monsoon. Shannon-Weaver diversity index was ranged from 1.992 to 2.114, whereas Simpson’s dominance index value was a maximum of 0.883 in pre-monsoon and a minimum of 0.852 in monsoon. The yearly fish production of the beel was 7.023 metric tons during experimental year. Besides this, small indigenous species (SIS) of fish dominated with 63.34% of the beel's species makeup. Nevertheless, the abundance and diversity of fish species are diminishing daily in this beel. For preserving the fish diversity of Bamui beel calls for the implementation of effective fishery management practices, vigilant monitoring to prevent overfishing, and a strong emphasis on raising awareness among fishermen.

Macrobenthic fauna and the ecological status of a shellfish farm in the Mediterranean Sea (Algeria)

A faunistic and ecological study on the benthic macrofauna was carried out in the shellfish farm in Ain Chorb (Ain Taya), central Algeria. This study aims to characterise the composition, structure, and functioning of the benthic community to establish the reference state and ecological quality of the shellfish farm and to monitor its evolution through an adapted sampling and observation methodology adapted and used by the scientific community at the international level. Benthic fauna samples were collected in two different periods (warm and cold season) between February 2020 and June 2021; six grab samples were carried out at three sampling stations. Different indices were evaluated based on the benthic community characteristics (species richness, abundance, density, ecological and trophic groups, and the biotic index) and indicator species. An inventory of the macrobenthic fauna of the farm allowed us to identify 6 phyla, 10 classes, 48 families, 106 genera, and 138 species, with a total of 45960 ind/m2. The benthic assemblage is characterised by the dominance of the species Abra alba, Salvatoria clavata, Caecum spp., and Bittium spp. The results of the four benthic indices (the Shannon-Weaver diversity index [H′], the AZTI Marine Biotic Index [AMBI], the multivariate AZTI Marine Biotic Index [M-AMBI], and the BENTIX) indicated that that the sampling stations have a moderate and good ecological status. These results were confirmed by the abundance/biomass comparison curves and geometric abundance class methods. This study provides the first inventory and represents the reference state of the soft-bottom communities of the aquaculture farm. The findings also indicate that the macrobenthic assemblage is excellent indicator of the ecological status.

Effect of Environmental Variables on Zooplankton in Various Habitats of the Nile River

The present study investigated the effect of environmental variables on the abundance and distribution of zooplankton in different habitats along the Nile River in Shattura Village. Zooplankton samples were collected from three distinct sites along the Nile River in Shattura Village, each exhibiting different environmental characteristics: Site 1 with vegetation, site 2 lacking vegetation, and site 3 being a drain canal. The study spanned from spring 2020 to winter 2021, during which the physico-chemical parameters of the water were analyzed. Rotifera constituted the majority of the zooplankton (54.73%), followed by Cladocera (20.59%), Copepoda (13.1%), and Ostracoda (8.9%). Among the 52 identified zooplankton species, Rotifera comprised 18 species, Cladocera 13 species, Copepoda 10 species, and Ostracoda 11 species. Site 1 exhibited the highest zooplankton density (44.08%), attributed to the presence of vegetation, followed by site 3 (37.18%), influenced by agricultural drains, and site 2 had the lowest density (18.73%). Zooplankton abundance peaked in summer and declined in winter. Notably, Rotifera abundance increased in populated sites (site 3), whereas other zooplankton groups thrived in less populated areas. Correlation analyses revealed positive associations between Rotifera and Cladocera with electric conductivity, total dissolved solids (TDS), chloride (Cl), calcium (Ca), and sulfate (SO4). Conversely, Copepoda showed positive correlations with water transparency, pH, dissolved oxygen, and biological oxygen demand (BOD). Overall, seasonal variations significantly impacted the zooplankton community, with Rotifera dominating and Ostracoda being the least abundant. High values of the Shannon–Weaver diversity index, richness, and evenness suggested ample food resources and favorable growth conditions. Transparency, conductivity, pH, dissolved oxygen, and BOD were identified as the key influencing parameters on zooplankton abundance. Additionally, vegetation and agricultural drains strongly influenced total zooplankton levels.

Dynamics of fish community structure in the Yeosu Coast, Korea: A comprehensive analysis of daily set-net catch data during 2008–2022

This study focuses on the Yeosu Coast, a critical ecological and economic zone on the Korean Peninsula. We conducted a comprehensive analysis of fish data obtained from daily set nets for the period of 2008–2022 (excluding 2017) to investigate variations in fish composition and community structure over a 15-year period. The catches were characterized by a prevalence of warm-water fish species, reflecting the temperate and subtropical character of the Yeosu Coast. The total catch during the study period was 3210.8 tonnes, with 2010 and 2016 registering the highest and lowest catches, respectively. Our analysis identified sea surface temperature as a primary factor correlated with these changes in species composition. The two dominant species, Scomberomorus niphonius (Cuvier, 1832) and Engraulis japonicus Temminck et Schlegel, 1846 together accounted for a remarkable 78.9% of the total catch. Notably, the Shannon–Weaver diversity index values were lower in 2015 than in 2008, indicating potential shifts in the community structure. Our analysis identified sea surface temperature as the most dominant factor that influenced these changes in species composition. Furthermore, we highlight the significant threats posed by climate change and the increasing number of jellyfish challenging fisheries on the Yeosu Coast. These threats have the potential to result in diminished set-net catches and declining biodiversity within this valuable ecosystem. Our findings underscore the importance of monitoring and addressing these ecological shifts to ensure the long-term sustainability of Yeosu Coast fisheries.

Root Architectural Adaptations to Phosphorus Deficiency: Unraveling Genotypic Variability in Wheat Seedlings

Understanding the changes in the root system architecture of bread wheat under phosphorus (P)-limited conditions is critical for identifying specific traits contributing to improved P uptake. Phenotypic variability in root, biomass, and P index-related traits among 204 diverse wheat genotypes at the seedling stage was examined under low and optimum P treatments. Strong genotypic and phenotypic associations between P utilization efficiency (PUtE) and total root volume, dry weight of root and shoot, total P uptake, and total plant biomass were observed under optimum P. Under low P, strong positive correlations between PUtE and total root length, total root volume, total surface area, and total biomass were observed, while it was negatively correlated with average diameter. These traits exhibited medium to high heritability. Under low P, average root diameter, primary root length, root mass ratio, total root tips, and surface area showed high Shannon–Weaver diversity index (H’) values (>0.79). The agglomerative hierarchical clustering analysis grouped the genotypes into four distinct clusters. The best performing genotypes in Clusters I and II indicated their strong relationship with P use efficiency due to higher percent increases in total root length, total surface area, total root volume, total root tips, total biomass, P efficiency ratio, specific root length, and PUtE under low P as compared to optimum P conditions. The present study identified specific root system architectural traits and P use-efficient genotypes (SHANGHAI, Pavon F76, BWL 5233, SONALIKA, KHARCHIA LOCAL, WH 102, BWL 4425, HD 2888.2, CBW 12, MN75136/PGO, KRL 19, and WH 1022) associated with efficient P uptake and utilization. These identified genotypes and traits may be useful in wheat breeding programs to develop P-efficient varieties with better adaptations for sustainable agriculture.

The impact of Eucalyptus plantations on herpetofaunal diversity, Maputo National Park, Mozambique

ABSTRACT Exotic afforestation has proven detrimental to biodiversity in general, however only a few studies documenting the impact of timber plantations on herpetofaunal diversity have been published within a southern African context. To determine if variations in herpetofaunal species assemblages could be detected between derelict Eucalyptus plantations, cleared plantation woodlots, and untransformed sand thicket vegetation, a pitfall and funnel trap survey was conducted in coastal southern Mozambique. Herpetofaunal species richness for derelict Eucalyptus plantations was 13 ± 2.24 species, untransformed sand thicket vegetation 17 ± 2.34 species and cleared plantation woodlots 18 ± 3.14 species. Both Shannon-Weaver and Simpson Diversity Indices estimated the highest herpetofaunal species diversity in untransformed sand thicket vegetation and the lowest diversity in derelict Eucalyptus plantations. The herpetofaunal species assemblages of derelict Eucalyptus plantations and natural sand thicket vegetation were least similar (0.507 ± 0.041), while cleared plantation woodlots and derelict Eucalyptus plantations were most similar (0.753 ± 0.032) in terms of herpetofaunal community composition. In contrast to our expectations, significantly higher capture rates were reported for a fossorial anuran in derelict Eucalyptus plantations compared to both cleared plantation woodlots and untransformed sand thicket vegetation, which requires further investigation and discussion. As with most other studies investigating the effects of exotic timber plantations on biodiversity, our results indicate that the detectable herpetofaunal diversity decreased in Eucalyptus plantations when compared to natural or cleared plantation woodlots. Subsequently it would seem as though the active clearing of dilapidated timber plantations as part of rehabilitation efforts may positively affect herpetofaunal diversity.

Seasonal Distribution of Copepods as Influenced by Physicochemical Parameters in Khanki Headworks, Pakistan

Copepods are tiny aquatic animals. Their role in aquatic food chains is very crucial as they are involved in organic matter circulation and energy transfer between different trophic levels. They are important source of food for fish larvae and zooplanktivorous fish. Objective: To assess the influence of environmental variables on the abundance, diversity and seasonal variations of planktonic copepods in Khanki Headworks, Pakistan. Methods: For the analysis of environmental variables monthly water samples from four selected sites were collected for a period of one year (February 2021 to January 2022). Environmental variables were analyzed in laboratory by following standard procedures. Month wise samples of copepods were collected with planktonic net (mesh size: 37µm) from four locations (each with 3 sub-sites). Results: In total, 7 species of Copepods belonging to 4 genera were identified from February 2021 to January 2022. Mesocyclops was observed as the most diverse genus (4 species), while Mesocyclops edax was the most prevalent copepod species. Population density and biodiversity were highest in June and minimum in January. Shannon-Weaver diversity index described greater diversity among copepod species in June. Pearson correlation and canonical correspondence analysis (CCA) revealed that electrical conductivity (EC), temperature, turbidity, pH and dissolved oxygen (DO) were important environmental variables affecting the biodiversity and density of copepods. Conclusions: This investigation elucidated that physicochemical parameters generally regulate the population dynamics of Copepods.

Uterine microbial profiles in healthy postpartum dairy cows do not vary with sampling techniques or phases of estrous cycle

In this study, we aimed to compare uterine microbial profiles in postpartum dairy cows, determined by bacteriological culture and next-generation sequencing, using three uterine sampling techniques (swab, cytobrush, and lavage) and induced phases of the estrous cycle (estrus and diestrus). Fifteen healthy postpartum dairy cows at 53 ± 5 days postpartum were enrolled in the study. Uterine samples were collected during a fixed-time artificial insemination protocol. Viable bacteria were aerobically cultured from part of each sample, and bacterial isolates were identified through Sanger sequencing of the 16S rRNA gene. Total genomic DNA was extracted from the remainder of undiluted samples to quantify bacterial load using 16S rRNA qPCR and characterize the microbiome by metagenomic sequencing of the V1–V3 region of the 16S rRNA gene. Microbial profiles and composition were analyzed using the Shannon-Weaver diversity index and principal component analysis, respectively. Out of 87 samples, 88 % (77/87) were culture positive. The proportion of culture-positive uterine samples did not differ between sampling techniques (P = 0.39) or estrous cycle phases (P = 0.99). However, swab, cytobrush, and lavage techniques yielded 1.5, 9 and 9 times greater bacterial loads (P < 0.01), respectively, during diestrus than estrus phase. Moreover, during diestrus phase, the cytobrush method yielded 3 and 6 times more bacteria (P < 0.01) than both the lavage and swab methods. The most abundant bacterial genera identified from both bacteriological culture and metagenomic sequencing were Bacillus and Enterococcus, regardless of sampling technique or phases of the estrous cycle. Bacterial genera in moderate to low abundance through metagenomic sequencing included Streptococcus, Oscillospiraceae, and Lachnospiraceae. Notably, the uterine microbial profiles and composition, determined by metagenomic sequencing, did not differ by sampling techniques (P = 0.55 and P = 0.60, respectively) or estrous cycle phases (P = 0.34 and P = 0.17, respectively). In conclusion, our results suggest that any of the sampling techniques can be reliably used to study the uterine microbiome of healthy cows at random phases of the estrous cycle. However, it is important to consider potential differences in bacterial yield as a confounding factor.

Multi-environment phenotyping of linseed (Linum usitatissimum L.) germplasm for morphological and seed quality traits to assemble a core collection

Linseed or flax (Linum usitatissimum L.) is one of the most ancient industrial crops domesticated for oilseed and natural fiber. India is one of the two proposed centers of origin of linseed and harbours high genetic diversity. The Indian Council of Agricultural Research-National Bureau of Plant Genetic Resources (ICAR-NBPGR) conserves one of the largest base collections of Linum with around 2800 germplasm accessions at National Genebank, of which 2576 are the unique accessions of cultivated linseed and were characterized for 10 qualitative and 26 quantitative traits and the resultant multi-environment data along with passport information was used to develop a multipurpose core collection. Initially, five different core sets were derived using the core collection assembler tool ‘Core Hunter 3’ by optimization of average genetic distances between each accession and nearest entry in the core (A-NE) and the average distance between each entry and nearest neighbouring entry (E-NE). These five core sets were subjected to different quality evaluation indices to select one set that best represents the maximum genetic diversity and representativeness present in the entire tested collection. The Core collection-4, developed with weightage of E-NE and A-NE in the ratio of 0.7–0.3 was chosen as the best core collection as it exhibited desirable genetic distance, variance difference percentage (VD; 85%), coincidence rate of range (CR; 91.66%) and variable rate of coefficient of variance (VR; 117.76%), which were more than threshold value of VD (80%), CR (80%), and VR (100%) required for an optimally good core collection. Several summary statistics, Kullback-Leibler distance and Shannon Weaver diversity index indicated similar trait distribution patterns among the chosen core set and the entire collection. Correlogram and principal component analysis revealed that trait associations and their magnitude were conserved for most of the traits in the chosen best core collection. The development of this multipurpose core collection is expected to cater to the needs of linseed breeders and germplasm curators to pave the way for expedited access to genetically diverse and agronomically important material for trait introgression.

The Development of Thematic Core Collections in Cassava Based on Yield, Disease Resistance, and Root Quality Traits.

Thematic collections (TCs), which are composed of genotypes with superior agronomic traits and reduced size, offer valuable opportunities for parental selection in plant breeding programs. Three TCs were created to focus on crucial attributes: root yield (CC_Yield), pest and disease resistance (CC_Disease), and root quality traits (CC_Root_quality). The genotypes were ranked using the best linear unbiased predictors (BLUP) method, and a truncated selection was implemented for each collection based on specific traits. The TCs exhibited minimal overlap, with each collection comprising 72 genotypes (CC_Disease), 63 genotypes (CC_Root_quality), and 64 genotypes (CC_Yield), representing 4%, 3.5%, and 3.5% of the total individuals in the entire collection, respectively. The Shannon-Weaver Diversity Index values generally varied but remained below 10% when compared to the entire collection. Most TCs exhibited observed heterozygosity, genetic diversity, and the inbreeding coefficient that closely resembled those of the entire collection, effectively retaining 90.76%, 88.10%, and 88.99% of the alleles present in the entire collection (CC_Disease, CC_Root_quality, and CC_Disease, respectively). A PCA of molecular and agro-morphological data revealed well-distributed and dispersed genotypes, while a discriminant analysis of principal components (DAPC) displayed a high discrimination capacity among the accessions within each collection. The strategies employed in this study hold significant potential for advancing crop improvement efforts.

Türkiye’nin Sınıraşan Akarsularından Kura-Aras Nehir Havzaları Su Kalitesinin Bazı Biyotik İndekslere Göre Değerlendirilmesi

This study aimed in the Kura-Aras river basin, which is the transbourdary system of Türkiye, to determine water quality by using some physicochemical parameters and macroinvertebrates. In the spring and autumn periods, benthic macroinvertebrates were collected by standard D-Frame Net and Ekman grab from stations. A total of 30 stations were selected along the basin. In this study, following BMWP (Biological Monitoring Working(Biological Monitoring Working Party), ASPT (Average Score Per Taxon), Simpson Diversity Index, Shannon-Weaver Diversity Index, Margalef Diversity Index. It was determined that the most dominant group was Insecta and the rarest group was Oligochaeta in the Kura- Aras River basin. As a result of the evaluation of the selected stations in the basin in terms of physicochemical parameters, it was determined that they showed 2nd and 3rd class water characteristics in terms of PO4-P and NH4–N. According to BMWP and ASPT biotic indexes, it has been determined that it has 3rd and 4th class properties.

Studying the Metazoan Zooplankton Community Characteristics and Evaluating the Water Quality Based on the Ecological and Functional Zones in Gaoyou Lake

To study the metazoan zooplankton community structure and water quality, we investigated the amount of metazoan zooplankton and the water quality in Gaoyou Lake from January to December 2022. Furthermore, we also evaluated the multi-index and nutritional status of Gaoyou Lake using the comprehensive nutritional status index of water quality, dominant population composition of the metazoan zooplankton, B/T index, and Shannon–Weaver diversity index based on the situation of each ecological and functional zone. The results indicated that the metazoan zooplankton of Gaoyou Lake included 21 families, 31 genera, and 63 species. The rotifers had 8 families, 16 genera, and 34 species, accounting for 53.9% of all species. The cladocerans had 6 families, 7 genera, and 16 species, which accounted for 25.4% of all species. The copepods had 7 families, 8 genera, and 13 species, that accounted for 20.7% of all species. The density and species of small metazoan zooplankton (rotifers) had a higher proportion than large metazoan zooplankton (crustaceans). The average annual metazoan zooplankton density was 1595.7 ind./L, the average annual biomass was 4.31 mg/L, the average annual total nitrogen (TN) was 1.101 mg/L, and the average annual total phosphorus (TP) was 0.082 mg/L. The TN and TP of the Gaoyou Lake were over the standard. The comprehensive nutritional status indices of the water quality in the entire lake and the ecological and functional areas were consistent with the metazoan zooplankton evaluation results, which determined that Gaoyou Lake showed mild eutrophication.

Biomonitoring of Kulla Beel, a Flood Plain Wet-land, Using Benthic Macro Invertabrates

Kulia beel, a flood plain wetland, located in Nadia District of West Bengal is surrounded by hospital, industries and human settlements. In the present study the ecological assessment through biomonitoring was done by using benthic macroinvertebrates collected from five sites during pre-monsoon, monsoon and postmonsoon periods. Average Shannon-Weaver diversity index (H) was found to vary from 0.953 at S2 during pre-monsoon to 1.683 at S3 during post-monsoon. The evenness index (1) varied from a maximum average value of 0.998 at site S-4 to a minimum average value of 0.614 at site S-1 during pre-monsoon seasons. Both the indices indicate the water body to be moderately polluted.

Analysis of marine diversity and anthropogenic pressures on Seixas coral reef ecosystem (northeastern Brazil)

Coral reefs, vital and ecologically significant ecosystems, are among the most jeopardized marine environments in the Atlantic Ocean, particularly along the northeastern coast of Brazil. The persistent lack of effective management and conservation has led to fragmented information on reef use and pressures, hindering the understanding of these ecosystems' health. Major difficulties and challenges include inadequate data, diverse anthropogenic pressures, and the complex interaction between marine species. This study sought to bridge this knowledge gap by conducting a comprehensive analysis of marine diversity and anthropogenic pressures, specifically focusing on Seixas coral reef near João Pessoa city, an area notably impacted by tourism. Utilizing 25 monitoring transects, subdivided into 1 m2 quadrants, the marine diversity was meticulously evaluated through innovative procedures including (a) sedimentological and geochemical field surveys, (b) application of Shannon-Weaver diversity and Simpson dominance indices, (c) cluster analysis, (d) species identification of macroalgae, coral, and fish, and (e) an examination of anthropogenic interactions and pressures on the coral reef. The assessment encompassed three distinct zones: Back Reef, Reef Top, and Fore Reef, and identified a total of 25 species across 15 genera and 10 fish families. The findings revealed the prevalence of brown macroalgae, fish, and coral, with heightened abundance of red macroalgae in the Fore Reef, which also exhibited the greatest diversity (2.816) and dominance (0.894). Original achievements include the identification of specific spatial variations, recognition of the anthropogenic factors leading to ecological changes, and the formulation of evidence-based recommendations. The study concludes that escalating urbanization and burgeoning daily tourist visits to the reef have exacerbated negative impacts on Seixas coral reef's marine ecosystem. These insights underscore the urgent need for strategic planning and resource management to safeguard the reef's biodiversity and ecological integrity.

Phytoplankton Community Structure, Diversity, and Functional Groups in Urban River Under Different Black and Odorous Levels

Phytoplankton community characteristics, diversity, and functional group analysis can respond to the environmental quality status of water bodies. To investigate the influence of urban river black odors on the phytoplankton community, from November 2020 to March 2021, 16 urban rivers in the Sichuan Basin were surveyed for water quality with 38 sampling points, and the degree of urban river black odor was evaluated based on the improved fuzzy mathematical model method and the k-mean principal color extraction method. The rivers were classified into four types:non-black and non-odorous, black and non-odorous, black and odorous, and black and odorous. The results showed that, with black and odorous water, the phytoplankton abundance increased from 1.329×105 cells·L-1 to 6.627×105 cells·L-1, and the dominant phytoplankton phylum decreased from Cyanophyta-Chlorophyta-Bacillariophyta to Cyanophyta. The phytoplankton biomass increased from 64.056 μg·L-1 to 120.465 μg·L-1, and the dominant phytoplankton phylum changed from Chlorophyta-Bacillariophyta type, adapted to a nutrient environment, to Pyrrophyta-Bacillariophyta-Cryptophyta type, adapted to an organic matter environment. The Shannon-Weaver diversity index decreased from 2.45 to 1.98, and Simpson's index decreased from 0.84 to 0.73. Twenty nine functional groups of phytoplankton were observed in the study area, and the growth strategy was reduced from S, R, C, CR, and CS to R with black and odorous water. In summary, phytoplankton indicators can better reflect the state of river black odor, and phytoplankton monitoring is a promising tool for urban river black odor management.

Exploring agro-morphological profiles of Phaseolus vulgaris germplasm shows manifest diversity and opportunities for genetic improvement

Common bean (Phaseolus vulgaris) is a seed crop with huge potential to contributing to food security in developing countries. In crop improvement, assessing genetic variability is a decisive step, requiring characterization of available crop germplasm. The present study aims at characterizing 39 common bean genotypes from various locations in Cameroon and five from Kenya using 19 qualitative and 36 quantitative traits of high descriptive values. Diversity among germplasm was assessed by determining diversity indices and carrying out multivariate analysis. Seventeen out of the nineteen qualitative traits (89.47%) were polymorphic, displaying each at least two phenotypic classes. High diversity was found. Average observed and expected number of phenotypic classes per trait were 3.74 and 2.53 respectively. Nei's genetic diversity value of 0.49 and Shannon-Weaver diversity index estimates of 0.74 were found. Significant differences were observed among genotypes for all measured quantitative traits. Yield traits showed significant correlation with other related quantitative traits. Cluster analysis separated the studied germplasm into three distinct groups, with the clustering pattern not showing any connection with location. The test of equality revealed significant difference between these clusters for most quantitative traits. Mahalanobis D2 statistics revealed germplasm of cluster I and III as potential parents for future breeding programs. This study identified genotypes with desirable agronomic traits such as higher number of seeds per pod, lower number of days to maturity, higher number of pods per plant, and higher yield. These and other important discriminatory traits are discussed and proposed for genetic improvement of common bean.

Phenotypic Characterization, Evaluation, and Classification of Cassava (Manihot esculenta Crantz) Accessions in Ethiopia

Cassava has a crucial role in benefiting smallholder farmers as the main food and income source in southern Ethiopia. Characterization accessions are crucial for assessing variation, classifying, and identifying desirable accessions for crop improvement and conservation. In this regard, there needs to be more information on the morphological characterization and classification cassava accessions. Thus, the aim of this research was to systematically characterize, evaluate, and classify cassava accessions using qualitative characters to provide useful information for breeding program and conservation. A total of 64 accessions were planted using a simple lattice design during the 2020-2021 cropping season. Thirty qualitative data were collected at 3, 6, 9, and 18 months after planting and analyzed using the SAS and R-software packages. The high variable characteristics were the shape of the central leaflet, petiole color, leaf retention, branching habit, the color of the stem epidermis, the color of the stem exterior, the external color of the storage root, and the color of the root pulp towards frequency distribution analysis. The Shannon–Weaver diversity index ranged from 0.24 to 1.47, with an overall mean of 0.84. The first three dimensions in the multiple correspondent method explained approximately 39.39% of the total variation, with Dim 1 accounting for 20.77% and Dim 2 accounting for 9.98%, while petiole color and texture of the root epidermis were the leading contributors to the total variation, respectively. In clustering analysis, 64 accessions were classified into 4 clusters of varying sizes. The distribution of accessions in each cluster revealed that 52 accessions were in cluster I, 6 in cluster II, 5 in cluster III, and 1 in cluster IV. Each cluster was varied by a major group characteristic that it represented. Furthermore, the study identified the desirable accessions for desired storage root characteristics such as root constrictions, the external color of the storage root, the color of root pulp, the color of the root cortex, and cortex peeling tendency. In conclusion, the various analyses performed indicated the existence of sufficient genetic variability for the characteristics evaluated, which could be attributed to the dissimilar genetic backgrounds of the evaluated accessions. Thus, these could be utilized for breeding work and conservation.