Trait diversity, heritability and genetic advance in selected germplasm lines of tef

The genetic improvement of the Ethiopian cereal, tef, Eragrostis tef (Zucc.) Trotter, depends upon the variability in the indigenous germplasm. A bi-replicated randomized complete block field experiment was, therefore, carried out at Debre Zeit and Alem Tena in Ethiopia during the 1996 main season to study the pheno-morphic and agronomic trait diversity in 320 tef germplasm lines. All of the 17 traits assessed showed substantial (p < or = 0.001) variation among the lines. Genotypes and locations interacted significantly (p < or = 0.05) on 11 of the traits. At about 50% similarity level, the tef lines grouped into six major clusters of nine to 243 lines. Five principal components (PCs) extracted about 71% of the entire variation of the lines. About 28% of the total variance explained by the first PC was due chiefly to variation in main shoot culm length, diameters of the two basal culm internodes, panicle length and grain yield/panicle. About 16% of the whole variance explained by the second PC originated mainly from variation in the length of the first and second basal culm internodes, grain yield/plant, and peduncle length. The third PC accounting for about 12% of the entire variance resulted largely from variation in harvest index and shoot phytomass yield/plant. Across traits, the phenotypic and genotypic coefficients of variation varied in that order from about 2% for grain yield/panicle to 58% for number of fertile tillers/plant, and from less than 1% for diameters of the two basal culm internodes and grain yield/panicle to 35% for panicle length. Estimates of broad sense heritability and genetic advance (as ratio of the mean) were highest for panicle length (71%) and number of fertile tillers/plant (21%), respectively. But both of these were lowest for the second basal culm internode diameter (< 1%). Overall, the study confirmed that tef is a highly versatile crop with broad trait diversity in the germplasm, and this offers ample opportunities for improvement through breeding.     

The Prevalence of Precancerous Cervical Cancer Lesion among HIV-Infected Women in Southern Ethiopia: A Cross-Sectional Study

Introduction

The magnitude of precancerous cervical cancer lesions as well as invasive cervical cancer is higher in HIV-infected women than non HIV-infected women. Thus, screening targeting HIV-infected women is being undertaken in developing countries, including Ethiopia. However, data on the prevalence and determinants of precancerous cervical cancer lesion among HIV-infected women in southern Ethiopia is lacking. Thus, this study aimed to assess the prevalence of and factors associated with precancerous cervical cancer lesion among HIV- infected women in southern Ethiopia.

Methods

A hospital-based cross-sectional study was conducted from October 2012 to February 2013 among HIV-infected women in Southern Ethiopia. Four hundred forty eight HIV-infected women who had been screened and treated for precancerous cervical cancer lesion were included in the study. Data were collected by using structured and pretested questionnaire. Visual inspection with acetic acid was applied for screening and treatment. SPSS version 16.0 was used for data entry and analysis. Logistic regression analysis was fitted and odds ratios with 95% Confidence intervals and p-values were computed to identify factors associated with precancerous cervical cancer lesion.

Results

Out of 448 study participants, 99 (22.1%) were found to be positive for precancerous cervical cancer. Being currently on highly active antiretroviral treatment (AOR=0.52, 95%CI: 0.35, 0.92), history of sexually transmitted disease (AOR=2.30, 95%CI: 1.23, 4.29) and having only one lifetime sexual partner (AOR=0.33, 95%CI: 0.20, 0.56) were factors associated with precancerous cervical cancer lesion.

Conclusions

The prevalence of precancerous cervical cancer lesion among HIV-infected women in southern Ethiopia was found to be high. Intervention to access all HIV-infected women like scaling up the limited services and awareness creation should be undertaken. Measures aimed at preventing the acquisition and transmission of sexually transmitted diseases and reducing the number of sexual partners are required. Besides, early initiation of highly active antiretroviral treatment is important.     

Population genetic structure and adaptation of malaria parasites on the edge of endemic distribution

To determine whether the major human malaria parasite Plasmodium falciparum exhibits fragmented population structure or local adaptation at the northern limit of its African distribution where the dry Sahel zone meets the Sahara, samples were collected from diverse locations within Mauritania over a range of ~1000 km. Microsatellite genotypes were obtained for 203 clinical infection samples from eight locations, and Illumina paired‐end sequences were obtained to yield high coverage genomewide single nucleotide polymorphism (SNP) data for 65 clinical infection samples from four locations. Most infections contained single parasite genotypes, reflecting low rates of transmission and superinfection locally, in contrast to the situation seen in population samples from countries further south. A minority of infections shared related or identical genotypes locally, indicating some repeated transmission of parasite clones without recombination. This caused some multilocus linkage disequilibrium and local divergence, but aside from the effect of repeated genotypes there was minimal differentiation between locations. Several chromosomal regions had elevated integrated haplotype scores (|iHS|) indicating recent selection, including those containing drug resistance genes. A genomewide F_ST scan comparison with previous sequence data from an area in West Africa with higher infection endemicity indicates that regional gene flow prevents genetic isolation, but revealed allele frequency differentiation at three drug resistance loci and an erythrocyte invasion ligand gene. Contrast of extended haplotype signatures revealed none to be unique to Mauritania. Discrete foci of infection on the edge of the Sahara are genetically highly connected to the wider continental parasite population, and local elimination would be difficult to achieve without very substantial reduction in malaria throughout the region.     

Electron transfer reaction of cytochrome c peroxidase at tin oxide electrodes

The unmediated one-electron reduction and reoxidation of ferric cytochrome c peroxidase at fluoride-doped tin oxide electrodes is reported. A long range interfacial electron transfer distance of 17 A is postulated by analogy to the Poulos/Kraut model for the cytochrome c peroxidase/cytochrome c electron transfer complex. The utility of the interfacial electrochemical approach for investigating cytochrome c peroxidase electron transfer behavior is discussed.     

Floristic composition,structure and regeneration status of Masha forest,south‐west Ethiopia

The natural forest of Masha was studied to determine the species composition and population structure of woody species in the area. A total of 130 plant species belonging 61 families were recorded, in which family Acanthaceae was represented by 11 species followed by Rubiaceae (10) and Asteraceae (9). The composition and population structure of woody species, with diameter at breast height (DBH) >2.5 cm and height >2 m, and their regeneration were assessed in 65 sample plots of 400 m² each. The density for trees and shrubs with DBH >2.5 cm was 1681 ind.ha^?1, and the basal area of the study area was 142.6 m² ha^?1. Four community types were recognized. This forest is of international and national conservation importance given its high biodiversity. Managing the remaining forest would be an appropriate option for sustainable management of biodiversity.     

Agrobiodiversity and gender: the role of women in farm diversification among smallholder farmers in Sinana district,Southeastern Ethiopia

Biodiversity and Conservation - Women’s knowledge and conservation of agrobiodiversity are under-valued and less documented and recognized in the scientific spheres regardless of the...