Influence of Organization and Coordination of Laboratory Facilities on Students’ Achievement in Physics in Secondary Schools of Njoro Sub County, Nakuru County, Kenya

Physics is a science subject that provides the foundation of industrial, technological and economic development of any country. Despite this, student’s achievement in the Kenya Certificate of Secondary Examination (KCSE) physics in Njoro Sub County has been poor over the years. The unsatisfactory performance may perhaps be due to Management of Laboratory Facilities (MLF). This study examined the influence of organizing and coordination of Laboratory Facilities on students’ achievement in physics in public secondary schools in Njoro Sub County.  The study adopted the descriptive survey research design. The target population of the study comprised of all the 8229 students and 60 physics teachers in public secondary schools in Njoro Sub County. The accessible population was all the 60 physics teachers and 2385 form two students in the 35 public schools in sub county schools.  A sample of 53 physics teachers and 343 form two students who participated in the study were selected using purposive, stratified, proportionate and simple random sampling techniques. A student’s physics practical achievement test (SPPAT), laboratory facility checklist (LFC) and physics teacher laboratory facilities management questionnaire (PTMLFQ) were used to collect data. Data was analysed with the aid of the Statistical Package for Social Sciences (SPSS) version 24. The study established that organization of laboratory facilities has statistically significant influence on students’ achievement in physics. The study also revealed that coordination of laboratory facilities has statistically significant influence on students’ achievement in physics. The study recommends that the Ministry of Education through its various agents, to review its laboratory organisation and coordination policies. The Teacher Service Commission (TSC) should emphasise on the Teacher Performance Appraisal and Development (TPAD) to ensure students’ performance is monitored across all classes. Keywords: Organization, Coordination, Management of Laboratory Facilities, Student’s Achievemen

Evaluation of Technical Efficiency of Rabbit Production in Buuri Sub -County, Meru County, Kenya

Current rabbit production in Buuri Sub county stands at 1.2 Metric tons of meat against a potential of 8.4 Metric tons per year. This productivity gap is wide and indicative of poor and low performance of the enterprise in rural areas of Kenya and specifically Buuri Sub County. Thus the main objective of this study was to investigate the technical efficiency of rabbit production and its contribution to household food production and family welfare under conditions of resource scarcity. The technical efficiency of rabbit production was evaluated to explain the paradox behind the low productivity of rabbit enterprises in Buuri sub-county. A multistage simple random sampling procedure was employed to get 139 respondents for the study. A semi structured and pre-tested questionnaire was used to collect data from the selected small holder rabbit producers through face to face interview of the household heads. The study used descriptive statistics for the analysis of socioeconomic and institutional attributes of the rabbit producers. The stochastic frontier production parametric method was used for the efficiency analysis. The results showed mean technical efficiencies among the rabbit farms were 36.83%. The farmers are not producing the rabbit output at minimum costs.  Further the study found that the capital is the most important rabbit output enhancing variable among all studied parameters. The Tobit model results indicated that increased access to education, trainings and credit to the farmers led to improved rabbit efficiency. More importantly county government and non-governmental agencies should make deliberate attempts for improved farmer-extension and research linkage for better technology transfer and adoption by farmers, leading to more productive rabbit enterprises hence improved incomes and thus reducing poverty level among farmers. Keywords: Technical efficiency, rabbit breeds, efficiency, rabbit keeping, backyard farming enterprises, stochastic frontie

East African diploid and triploid bananas: a genetic complex transported from South-East Asia

All the edible AA varieties studied here are genetically homogeneous, constituting a unique subgroup, here called ‘Mchare’, despite high phenotypic variation and adaptions to highly diverse ecological zones. At triploid level, and besides the well-known AAA Mutika subgroup, at least two other genetically related AAA subgroups specific to this region are identified. Neither of these East African AAA genotypes can be derived directly from the local AA Mchare diploids. However, it is demonstrated that the East African diploids and triploids together belong to the same genetic complex. The geographical distribution of their wild acuminata relatives allowed identification of the original area of this complex in a restricted part of island South-East Asia. The inferred origin leads to consideration of the history of banana introduction in Africa. Linked to biological features, documentation on the embedding of bananas in founding legends and myths and convincing linguistic elements were informative regarding the period and the peoples who introduced these Asian plants into Africa. The results point to the role of Austronesian-speaking peoples who colonized the Indian Ocean islands, particularly Madagascar, and reached the East African coasts

Recent advances in understanding the roles of whole genome duplications in evolution

Ancient whole-genome duplications (WGDs)—paleopolyploidy events—are key to solving Darwin’s ‘abominable mystery’ of how flowering plants evolved and radiated into a rich variety of species. The vertebrates also emerged from their invertebrate ancestors via two WGDs, and genomes of diverse gymnosperm trees, unicellular eukaryotes, invertebrates, fishes, amphibians and even a rodent carry evidence of lineage-specific WGDs. Modern polyploidy is common in eukaryotes, and it can be induced, enabling mechanisms and short-term cost-benefit assessments of polyploidy to be studied experimentally. However, the ancient WGDs can be reconstructed only by comparative genomics: these studies are difficult because the DNA duplicates have been through tens or hundreds of millions of years of gene losses, mutations, and chromosomal rearrangements that culminate in resolution of the polyploid genomes back into diploid ones (rediploidisation). Intriguing asymmetries in patterns of post-WGD gene loss and retention between duplicated sets of chromosomes have been discovered recently, and elaborations of signal transduction systems are lasting legacies from several WGDs. The data imply that simpler signalling pathways in the pre-WGD ancestors were converted via WGDs into multi-stranded parallelised networks. Genetic and biochemical studies in plants, yeasts and vertebrates suggest a paradigm in which different combinations of sister paralogues in the post-WGD regulatory networks are co-regulated under different conditions. In principle, such networks can respond to a wide array of environmental, sensory and hormonal stimuli and integrate them to generate phenotypic variety in cell types and behaviours. Patterns are also being discerned in how the post-WGD signalling networks are reconfigured in human cancers and neurological conditions. It is fascinating to unpick how ancient genomic events impact on complexity, variety and disease in modern life

Molecular and cytological characterization of the global Musa germplasm collection provides insights into the treasure of banana diversity

© 2016, The Author(s). Bananas (Musa spp.) are one of the main fruit crops grown worldwide. With the annual production reaching 144 million tons, their production represents an important contribution to the economies of many countries in Asia, Africa, Latin-America and Pacific Islands. Most importantly, bananas are a staple food for millions of people living in the tropics. Unfortunately, sustainable banana production is endangered by various diseases and pests, and the breeding for resistant cultivars relies on a far too small base of genetic variation. Greater diversity needs to be incorporated in breeding, especially of wild species. Such work requires a large and thoroughly characterized germplasm collection, which also is a safe depository of genetic diversity. The largest ex situ Musa germplasm collection is kept at the International Transit Centre (ITC) in Leuven (Belgium) and currently comprises over 1500 accessions. This report summarizes the results of systematic cytological and molecular characterization of the Musa ITC collection. By December 2015, 630 accessions have been genotyped. The SSR markers confirmed the previous morphological based classification for 84% of ITC accessions analyzed. The remaining 16% of the genotyped entries may need field verification by taxonomist to decide if the unexpected classification by SSR genotyping was correct. The ploidy level estimation complements the molecular data. The genotyping continues for the entire ITC collection, including newly introduced accessions, to assure that the genotype of each accession is known in the largest global Musa gene bank. Open Access ispartof: Biodiversity and Conservation vol:26 issue:4 pages:801-824 status: publishe

The triploid East African Highland Banana (EAHB) genepool is genetically uniform arising from a single ancestral clone that underwent population expansion by vegetative propagation

East African Highland bananas (EAHBs) are a subgroup of triploid (AAA genome) bananas of importance to food security in the Great Lakes region of Africa. Little is known about their genetic variation, population structure and evolutionary history. Ninety phenotypically diverse EAHB cultivars were genotyped at 100 SSR microsatellite markers to investigate population genetic diversity, the correlation of genetic variability with morphological classes, and evolutionary origins since introduction to Africa. Population-level statistics were compared to those for plantain (AAB) and dessert (AAA) cultivars representing other M. acuminata subgroups. EAHBs displayed minimal genetic variation and are largely genetically uniform, irrespective of whether they were derived from the distinct Ugandan or Kenyan germplasm collections. No association was observed between EAHB genetic diversity and currently employed morphological taxonomic systems for EAHB germplasm. Population size dynamics indicated that triploid EAHBs arose as a single hybridization event, which generated a genetic bottleneck during foundation of the EAHB genepool. As EAHB triploids are sterile, subsequent asexual vegetative propagation of EAHBs allowed a recent rapid expansion in population size. This provided a basis for emergence of genetically near-isogenic somatic mutants selected across farmers and environments in East Africa over the past 2000 years since EAHBs were first introduced to the African continent

Genotyping the local banana landrace groups of East Africa

Crop landraces (largely resulting from adaptation and continuous selection by farmers) are more diverse within field populations than modern cultivars (produced by deliberate crossing), yet their distribution has continued to shrink in the past decades. The temporal dynamics of this shrinking is little known. The analysis of genetic variation within and between landraces is essential for making efficient breeding and conservation decisions with the available variability. Seven diploid landraces originally from Tanzania, 37 triploid landraces (24 East African highland bananas (EAHB); 5 'Ilalyi' (AAA genome), and 8 ill-defined types from Tanzania), 6 exotic triploids, and 3 exotic diploids originally from the International Transit Center were genotyped with simple sequence repeat (SSR) markers. This study sought to understand the genetic relationship between the EAHB and the diploid landraces and other banana groups (local triploid landraces, and introduced (exotic) cultivars) so as to decide whether to include the diploids in the breeding scheme of EAHB. Results showed the highest average genetic distance (degree of genomic difference by proportion) within the diploids (0.5666), followed by the hybrid triploids (0.4568) and the lowest within the 'Ilalyi' (0.0748) and the EAHB (0.0827) landraces. The variation within each clone set of EAHB was higher in 'Nakitembe' (0.0948) and 'Musakala' (0.1052). These two are commercial clone sets whose variation may be due to high and long-term selection pressure. In contrast, between the banana groups, the diploid landraces were more distant (highest average genetic distance) from the triploid landraces (0.4351-0.4430) and could thus provide useful breeding traits. On the other side, the triploid landraces had a narrow genetic base which should be broadened. Results did not identify those local east African diploids closest to the EAHB or other local triploids, although local diploids show breeding potential. This could widen the genetic base and probably improve performance of the triploid landraces

Assessment of the genetic diversity and pattern of relationship of West African sorghum accessions using microsatellite markers

An understanding of the extent, distribution and patterns of genetic variation is useful for estimation of any possible loss of genetic diversity and assessment of genetic variability and its potential use in breeding programs, including establishment of heterotic groups. This study assessed patterns of genetic diversity and relationships among 30 West African sorghum accessions using 22 microsatellite markers. Population structure and within population genetic diversity was also assessed using the same markers. Genotypic data was generated using the ABI Prism 3730 and alleles called and sized using genemapper software version 3.7. Molecular data was analyzed using DARwin 4.0, powermarker 3.0 and Ariequin version 3.11. The average marker quality index was 0.27 while a mean PIC of 0.54 was observed across the 22 SSR markers. Among the 30 accessions, the markers detect a total of 146 alleles with an average of 6.6 alleles per marker. Results from the various statistical analyses performed revealed a wide the average Nei's genetic diversity among the 30 population was lower at 0.54 and the average heterozygosity was also lower at 0.21. Cluster and principal cooridinate analysis of the 30 populations revealed two distinct groups independent of their geographic origins The examination of the hierarchical partitioning of genetic variation by AMOVA demonstrated that genetic differentiation was siginficant at P<0.00. Of the total diversity, 8.9% was attributed to country difference, 54.11% was attributed to population differences within the countries while 36.99% was attributed to differences within populations. The Fst value (0.63) indicated a very high genetic differentiation as expected for selfing species. This study demonstrates the utility of SSR markers in detecting polymorphism, estimating genetic diversity and establishment of genetic clusters for heterotic studie

Identification of genes associated with abiotic stress tolerance in sweetpotato using weighted gene co-expression network analysis

Sweetpotato, Ipomoea batatas (L.), a key food security crop, is negatively impacted by heat, drought, and salinity stress. The orange-fleshed sweetpotato cultivar “Beauregard” was exposed to heat, salt, and drought treatments for 24 and 48 h to identify genes responding to each stress condition in leaves. Analysis revealed both common (35 up regulated, 259 down regulated genes in the three stress conditions) and unique sets of up regulated (1337 genes by drought, 516 genes by heat, and 97 genes by salt stress) and down regulated (2445 genes by drought, 678 genes by heat, and 204 genes by salt stress) differentially expressed genes (DEGs) suggesting common, yet stress-specific transcriptional responses to these three abiotic stressors. Gene Ontology analysis of down regulated DEGs common to both heat and salt stress revealed enrichment of terms associated with “cell population proliferation” suggestive of an impact on the cell cycle by the two stress conditions. To identify shared and unique gene co-expression networks under multiple abiotic stress conditions, weighted gene co-expression network analysis was performed using gene expression profiles from heat, salt, and drought stress treated ‘Beauregard’ leaves yielding 18 co-expression modules. One module was enriched for “response to water deprivation,” “response to abscisic acid,” and “nitrate transport” indicating synergetic crosstalk between nitrogen, water, and phytohormones with genes encoding osmotin, cell expansion, and cell wall modification proteins present as key hub genes in this drought-associated module. This research lays the groundwork for exploring to a further degree, mechanisms for abiotic stress tolerance in sweetpotato