Historical Development and Practical Application of Correlation and Path Coefficient Analysis in Agriculture

Correlation coefficient measures the mutual relationship between various plant characters and determines the component characters on which selection can be based for the improvement in associated complex character. Several correlation coefficients based on different statistical hypothesis are used today: Pearson correlation coefficient, Spearman ranks correlation coefficient and Spearman semi-quantitative correlation coefficient, Kendall tau-a, -b and -c correlation coefficients, Gamma correlation coefficient. In quantitative genetics there are three types of correlations and these are phenotypic, genotypic and environmental correlations. Path coefficient analysis splits the correlation coefficients into the measures of direct and indirect effects of a set of independent variables on the dependent variable and estimated using a standardized partial regression coefficient known as path coefficient analysis, as suggested by Dewey and Lu in 1959.Based on this, data from national variety trial conducted at  Holetta agricultural research center was analyzed both for correlation coefficient(phenotypic and genotypic) and path coefficient. Phenotypic correlation coefficient between yield and plant height, ear height and ear per plant positive and significant and reveals that the relation is due to environmental influence. However, there is no genotypic correlation between yield and other studied trait which indicting that selecting one trait will not improve the other which refers most of the traits were influenced by environment more relatively. Phenotypic path coefficient analysis between, EH (0.406139) and PH (0.402022) showed positive and high direct effects, whereas genotypic path coefficient analysis the direct effect of EH (0.511255(and PH (0.511028) on GY was considerably higher. Keyword: correlation coefficient, path coefficient, phenotype, genotype, variance, models

Crop Evolution and Domestication Syndromes

Crops evolved through evolution and domestication process and different crops either have different or similar origin. Evolution and domestication process is progressing process starting with wild species, then formation of cultivated one and selection of improved strain of the species by growers and researchers. These processes may happen due to mutation, immigration, artificial selection, natural selection, speciation and cross. Evolution and domestication process then results difference among domesticated as well as evolved crops from their wild progenitors and this coined as syndromes. The syndromes discussed in this paper includes plant height and growth habit, flowering time inflorescence size and morphology, fruit size and morphology, organ color and toxic substance, seed size and dispersal and seed dormancy. As future direction, studying the wild species more and more and maintaining them enables to develop crops that are resist to biotic or abiotic stresses and obtaining yielding crops varieties. Keywords: Crop, Evolution, Domestication, Syndrome DOI: 10.7176/JNSR/9-12-01 Publication date:June 30th 2019

Review on Application of Plant Tissue Culture in Plant Breeding

Plant breeders employ a variety of techniques to improve the genetic composition of crops and a successful strategy is dependent on the physical, physiological and hereditary characteristics of the plant. Plant tissue culture is one of the method used in plant breeding used in disease free plant development, genetic transformation, Somatic embryogenesis, embryo rescue, and anther and ovule culture for post fertilizer barrier and polyploidy induction. It  play great role in plant/crop improvement as it involves in variation creation, conservation of germplasm and shorten the breeding cycle by developing homozygous parents with  single a generation. So, the review is designed to assess application of tissue culture in improvement of field crop, ornamental, forest tree or plants as whole for human benefits. Keywords: plant, tissue culture, breeding DOI: 10.7176/JNSR/9-3-0

Review on Concept and Impact of Double Haploid Techniques in Crop Improvement

Based on previous studies this review presents about double haploid technology and its role in crop improvement. Double haploids are plants those carry two sets of chromosomes that are created from the haploid plants. Different methods such as androgenesis (microspore or anther), gynogenesis (ovule or ovary) haploid inducer lines and wide crosses are used for developing haploid thereby double haploid. Though various chromosome doubling   agents found, colchicine has been widely using.  The successes of double haploid production relay on different factors like flower parts development stage, culture media, genotype, donor parent growth condition and haploid detection methods. This technology able shortens breeding cycle or time, complete genetic purity, efficient in genetic study, marker development, mutation and transformation better than traditional way of breeding. Generally, understanding DH technology has important contribution in accelerating breeding program for immediate reaction towards out breaking biotic and abiotic constraints and competitive to world market. Keywords: double haploid, haploid, crop improvemen

Combining Ability Analysis of Maize Inbred Lines in Ethiopia

The study was initiated to estimate combining ability of maize inbred lines and crosses using line by tester analysis. Fifty entries consists 48 F1 single crosses developed from 24 inbred lines and 2 testers using line x tester design and two commercial check hybrids used in the study. The experiment was conducted using alpha lattice design with two replications. Analysis of variance revealed existence of significant genetic variation among genotypes for all studied traits except for plant aspect (PA). Location x entry interaction for most of the traits was not significant which suggests hybrid performance was consistent across tested locations. Line x tester analysis of variance showed that mean squares due to GCA of lines were significant (p< 0.01 or p< 0.05) for all studied traits. Mean squares of tester GCA and SCA were significant for most of studied traits. This indicates that both additive and non-additive gene effects had contributed for the variation of the crosses. However, higher proportional contribution of additive gene action for all studied traits was obtained. Several lines and crosses were identified as good general and specific combiners for yield and yield related traits. Lines L23, L11, L15 and crosses L2xT1, L3xT1, L8xT1, L11xT1, L23xT1 and L13xT2 were found to be good general and specific combiners, respectively. In conclusion, the stated inbred lines with desirable gca effects and cross combinations with desirable sca effects for grain yield and yield related traits could be used as useful genetic material

Genotype x environment interaction and stability analysis of grain yield in QPM hybrid varieties

Maize (Zea mays L.) is a major staple cereal widely cultivated in different agro-climatic environments of Ethiopia.Maize productivity in the tropical highland region of the country is known by low average yield mainly due to thelack of high yielding and widely adapted improved cultivars. The objectives of this study were to determine G×Einteraction and yield stability of quality protein maize (QPM) experimental hybrids,to identify ideal genotype withhigh average yield depending on the differential genotypic responses to environment, and to form homogeneousgrouping of environments. The study was conducted at seven environments representing the tropical-highlandsub-humid maize growing agro-ecology of Ethiopia in 2015/2016. Thirty-three QPM hybrids and three-commercial hybridchecks were evaluated using a 4 ×9 alpha lattice design. Yield data was analyzed using AMMI and GGEbi-plot methods. Using AMMI analysis, four promising QPM hybrids designated asG31, G7, G19, G29, and G22were identified based on combined stability and average yield.GGEbi-plot displayed that variety Jibatwas closestto the ideal genotype, can be considered as best hybrid whereas G29, G22 were considered as desirably stable genotypes.GGE bi-plot also displayed Holeta as ideal environment and thus considered useful in discriminating thehybrids and representativeness as suitable environment. The GGE analysis delineated the test environments intothree mega-environments useful for targeted evaluation of genotypes. The result of this study indicated specificallyand widely adapted high yielding stable genotypes and also revealed homogeneous test environments

Tobacco use and its predictors among Ethiopian adults: A further analysis of Ethiopian NCD STEPS survey-2015

Background: Consuming any form of tobacco is one of the leading causes of preventable morbidity and mortality. Tobacco smoking has been identified as one of the major risk factors for NCDs, including cardiovascular, chronic respiratory diseases, and different cancers. Although there is national information on magnitude of tobacco use, to date there is limited nationally representative data on factors associated with tobacco use. The aim of this study is to assess the distribution and predicators of tobacco use in Ethiopian adult population between 15 -59.Objectives: The main aim of this study was to assess the prevalence of tobacco use and its predictor in Ethiopia.Methods: A cross-sectional population based study design was employed among population age from 15- 69 years. A stratified, three-stage cluster sampling was used to identify the study subjects. Households in each cluster were selected using simple random sampling method. The sampling frame was based on the population and housing census conducted for Ethiopia in 2007. Data was collected using WHO NCD STEPS questionnaire; current tobacco use of any type was taken as the dependent variable. Five hundred thirteen enumeration areas (EAs) as primary sampling units (PSUs) (404 rural and 109 urban) were selected with probability proportionate to size, followed by selection of households as a secondary sampling units (SSUs). A total of 10,260 households were selected from the 513 EAs (20 households per EA). Eligible individuals were selected from households using Kish method (a pre-assigned table of random numbers to find the person to be interviewed). Descriptive statistics using frequency table, mean, median, interquartile range and standard deviations were computed. Step wise logistic regression was used to analyse the predictors of tobacco use. An Estimator of 95% confidence interval was used both for computing descriptive statistics as well testing associations using logistic regression.Results: The prevalence of tobacco use (all tobacco products) was 4.2%. The mean age (± SD) of starting tobacco use was 21(7) years. The mean frequency of tobacco use was 2 times per day. Hierarchical Logistic regression analysis revealed that participants in age groups 30-44 years, and 60-69 years were less likely to use any tobacco type compared to younger age group of15-29 years. Heavy episodic drinking, AOR 2.46 [95% CI= 1.4 – 4.5], and khat chewing, AOR 4.71[95%= 2.26 – 9.8], were independently associated with tobacco use.Conclusion and recommendations: The overall prevalence of tobacco use was relatively higher in males. Factors associated with tobacco use were heavy episodic drinking and khat chewing. Although tobacco use is an important risk factor for different disease on its own, the additional use of these substances exposes individuals to increased risk of NCDs. The findings warrant the need to implement existing anti-tobacco laws in the country, enhance anti-tobacco awareness raising efforts, and implement interventions to help current tobacco users, focusing attention more on regions with high rates of tobacco use and males. Key words: Ethiopia, NCDs, Predictors, Risk factors, Tobacco use, WHO STEP

D.C.S.O Community Health Proposal Against COVID-19 - Public School System

D.C. is a community with a rich culture that’s extremely sundry and diversified. When the COVID-19 epidemic hit, all of us were stopped in our tracks. It affected our everyday lives. However we never asked the question, is there an epidemic taking place right in our own community. Asthma influences almost 1 out of every 10 kids. It is a widely known and exceptionally treatable malady (McDade, 2014). To ensure that students with asthma get adequate care during the school year and to combate the threat of COVID-19 during the year, we propose the following: To equip either classrooms or floors, especially for kids with asthma, with air purifiers that are going to circulate clean air so that they do not have any triggers like smells or mold Plan to make a questionnaire that every student has to answer before entering the school in the morning to help know of COVID-19 exposure and students with asthma. Train D.C. public schools teachers with C Diff cleaning procedures. After school programming that provides students with masks, soap, and hand sanitizers to take home.https://hsrc.himmelfarb.gwu.edu/dchapp/1011/thumbnail.jp

Optic nerve sheath diameter measurement using point-of-care ultrasound to assess intracranial pressure of adult patients with traumatic brain injury in resource-limited setting

Background: Traumatic brain injury is a disease with high mortality with increased intracranial pressure included in the emergency department. Neuroimaging and intracranial pressure monitoring are limited in resource-limited settings. Optic nerve sheath diameter measurement to assess intracranial pressure indirectly using point-of-care ultrasound is appealing in diagnostics and decision-making. Objectives: We plan to evaluate the utility of point-of-care ultrasound on optic nerve sheath diameter role in traumatic brain injury patients. In these patients, optic nerve sheath diameter measurement was performed immediately postoperatively and 24 h later by trained residents. The procedure was repeated if any change in clinical status was observed. Results: A total of 50 patients were enrolled. Twenty-one patients underwent neurosurgical intervention. Three patients died in hospital. Eighteen patients had optic nerve sheath diameters less than 5 mm, 20 patients had optic nerve sheath diameter between 5 mm and 6 mm, and 12 patients had optic nerve sheath diameter > 6 mm. In 2 patients with changes in clinical condition, the repeat optic nerve sheath diameter assessment showed an increase in optic nerve sheath diameter. Conclusion: Despite limitations, trained health care providers can perform optic nerve sheath diameter. Longer training time and quality assurance are needed to appreciate the impact

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population