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

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