Prospects for Genomic Selection in Cassava Breeding

Article purchased; Published online: 28 Sept 2017Cassava (Manihot esculenta Crantz) is a clonally propagated staple food crop in the tropics. Genomic selection (GS) has been implemented at three breeding institutions in Africa to reduce cycle times. Initial studies provided promising estimates of predictive abilities. Here, we expand on previous analyses by assessing the accuracy of seven prediction models for seven traits in three prediction scenarios: cross-validation within populations, cross-population prediction and cross-generation prediction. We also evaluated the impact of increasing the training population (TP) size by phenotyping progenies selected either at random or with a genetic algorithm. Cross-validation results were mostly consistent across programs, with nonadditive models predicting of 10% better on average. Cross-population accuracy was generally low (mean = 0.18) but prediction of cassava mosaic disease increased up to 57% in one Nigerian population when data from another related population were combined. Accuracy across generations was poorer than within-generation accuracy, as expected, but accuracy for dry matter content and mosaic disease severity should be sufficient for rapid-cycling GS. Selection of a prediction model made some difference across generations, but increasing TP size was more important. With a genetic algorithm, selection of one-third of progeny could achieve an accuracy equivalent to phenotyping all progeny. We are in the early stages of GS for this crop but the results are promising for some traits. General guidelines that are emerging are that TPs need to continue to grow but phenotyping can be done on a cleverly selected subset of individuals, reducing the overall phenotyping burden.Bill & Melinda Gates FoundationUKaidCGIAR Research Program on Roots, Tubers and BananasPeer Revie

Prevalence of helicobacter pylori infection in patients with gasto-duodenal diseases in Jos, Nigeria.

Helicobacter pylori (H. pylori) infection has become topical over the last three decades particularly with regards to its association with gastro duodenal disease. High prevalence rates of this ubiquitous bacterium have been reported in both symptomatic and asymptomatic subjects especially in low socioeconomics communities. Objective: the objectives of this study was to determine the prevalence of H. pylori infection in patients with gastroduodenal disease in Jos Nigeria. Method: a cross sectional study of consecutives patients referred for upper gastrointestinal endoscopy was carried out at the Jos University Teaching Hospital (JUTH) at endoscopy two pairs each of antral and corpus gastric biopsies were taken from each patient and evaluated for the presence H.pylori infection using the rapid urease test . result: the prevalence of h pylori from this study was found to be 90.1% in those with organic disease at endoscopy (organic dyspepsia) and 84% in those with no pathology detected at endoscopy (non-ulcer dyspepsia). There was no statistically significant difference in the prevalence rates of H. pylori in the two groups. (p value 0.0076) the prevalence of the bacterium in patients with organic disease at endoscopy showed the highest prevalence in those with duodenal ulcer 16/17 (94.1%) followed by duodenits 6/7 (85.7%) gastritis 8/9 (88.9%) and gastric ulcer ½ (50%) respectively. Four out of five (80%) of those with reflux oesophagitis and ½ (50%) of those with candida oesophagitis also tested positive to h. pylori. One patients each who had barretts esophagus and hiatus hermia were negative for h. pylori. Conclusion: helicobacter pylori infection in common among patients refereed for upper gastrointestinal endoscopy irrespective of the underlying pathology. this may be a reflection of the generally high prevalence rates of this ubiquitous bacterium in the community. Therefore, the presence of H. pylori infection should be interpreted with caution by clinicians before treatment. Evidence base protocol need to be developed by experts to guide clinicians in optimally caring for dyspeptic based protocols need to be developed by experts to guide clinicians in optimally caring for dyspeptic patients in our communit

Complement Levels in Nigeria Patients with Sickle Cell Anaemia in the Asymptomatic State

Objectives: Significantly low serum levels of complement components have been reported in patients with Sickle cell anaemia (SCA) which may result in a high susceptibility to infections. However some studies have reported a normal or high complement level. The aim of our study was to assess some haematological parameters and Complement levels in adult patients with steady state SCA in Zaria, North western Nigeria. This will serve as a guide towards infection surveillance in the quest to reduce significant morbidity and mortality in our setting.Methods: A cross sectional study of 40 patients with SCA in steady state and 40 healthy (non-matched) non-SCA controls at the Haematology clinic of Ahmadu Bello University Teaching Hospital Zaria, was carried out over a 6 month period in 2016. Institutional ethical approval and informed written consentwere obtained. Venous blood was analyzed for haematological parameters by an automated method and complement levels; alternative pathway was assessed by measuring C3, classical pathway by C4 and Terminal pathways by C5 levels using ELISA technique. Data was analyzed with statistical package for social science(SPSS) software version 20.0(2001) and a p value of ≤ 0.05 was considered significant.Results: The age range of patients with SCA and controls were 18 to 46years and 18 to 48years respectively and these were not significantly different p > 0.05. The median levels of C3 (245μg/ml), C4 (245μg/ml) and C5 (40μg/ml) were within normal range in the study subjects but significantly higher (p < 0.05), than those of the controls C3 (165μg/ml), C4 (125μg/ml) and C5(35μg/ml). Haematological parameters showed no correlation with the levels of Complement components studied.Conclusion: Although Complement components C3, C4, and C5 levels in patients with SCA are significantly high, the infectious susceptibility may be due to other immunological abnormalities.Keywords: Complement C3, C4, and C5, infection surveillance, sickle cell anemi

Keratoconjunctivitis sicca in a Tertiary Hospital in Lagos Nigeria

Background: Keratoconjunctivitis sicca is a growing public health problem and a common cause of ocular morbidity, which is often  unrecognized by eye care practitioners. It is also a cause of visual impairment and ocular discomfort. Recent changes in global climate may have contributed to the increased incidence and severity of the disease Objective: To determine the prevalence and identify risk factors for Keratoconjunctivitis sicca (KCS) in patients presenting at a tertiary ophthalmic center. Methods: The study was a cross-sectional descriptive hospital-based survey conducted at the Guinness Eye Centre of the Lagos  University Teaching Hospital (LUTH) between a one year period of November 2015 and October 2016. A total population sampling method was used. All new patients 16 years and above, that presented to the Eye Clinic during the study period who met the inclusion criteria and gave consent were included in the study. The participant's socio-demographic data were obtained and Keratoconjunctivitis Sicca was assessed using the Ocular Surface Disease Index (OSDI), Shirmer's Test and Tear Film Break Up Time (TFBUT). An OSDI score of ≥50 with a TFBUT of <10 seconds or Shirmer's Test reading of <10mm was considered diagnostic of KCS. In all data analysis and comparisons, a p value <0.05 was considered statistically significant. Results: A total of 300 eyes in 150 patients comprising 65 males and 85 females were analyzed. The average age was 47.4 ± 18.2 years and age range was 16-84 years. The prevalence of KCS was 54.3%. KCS was significantly associated with increasing age with a mean age of 50.3 years (p value= 0.031). The prevalence of KCS increased per decade of life and was seen in 72.2% of patients above the age of 70 years, was seen more in the female gender (prevalence of 56.5%), use of computer screen based technologies (55.7%) and cigarette smoking (odds ratio of 3.53). The positive predictive value of the OSDI was 53.2%. Conclusion: The prevalence of Keratoconjunctivitis Sicca is high especially in our evolving technological world today. There should be a high index of suspicion in patients who fit into the demographic of individuals with KCS. Therefore, screening should be done for such patients with the risk factors irrespective of their symptoms so that appropriate care may be rendered. Keywords: Keratoconjunctivitis Sicca, prevalence, risk factors&nbsp