High-Throughput Phenotyping of Canopy Cover and Senescence in Maize Field Trials Using Aerial Digital Canopy Imaging

In the crop breeding process, the use of data collection methods that allow reliable assessment of crop adaptation traits, faster and cheaper than those currently in use, can significantly improve resource use efficiency by reducing selection cost and can contribute to increased genetic gain through improved selection efficiency. Current methods to estimate crop growth (ground canopy cover) and leaf senescence are essentially manual and/or by visual scoring, and are therefore often subjective, time consuming, and expensive. Aerial sensing technologies offer radically new perspectives for assessing these traits at low cost, faster, and in a more objective manner. We report the use of an unmanned aerial vehicle (UAV) equipped with an RGB camera for crop cover and canopy senescence assessment in maize field trials. Aerial-imaging-derived data showed a moderately high heritability for both traits with a significant genetic correlation with grain yield. In addition, in some cases, the correlation between the visual assessment (prone to subjectivity) of crop senescence and the senescence index, calculated from aerial imaging data, was significant. We concluded that the UAV-based aerial sensing platforms have great potential for monitoring the dynamics of crop canopy characteristics like crop vigor through ground canopy cover and canopy senescence in breeding trial plots. This is anticipated to assist in improving selection efficiency through higher accuracy and precision, as well as reduced time and cost of data collection

Voluntary counseling and testing by nurse counselors: what is the role of routine repeated testing after a negative result?

Three hundred eighty-eight human immunodeficiency virus (HIV)-negative clients in Zimbabwe were retested at 3 months using 2 parallel rapid tests. One operator error (risk, 0.26%; 95% confidence interval, 0.0065%-1.4%) and no "true" seroconversions (upper 95% confidence limit, 0.96%) were detected. High-risk behavior was not significantly reduced. Policies recommending routine retesting need to be reconsidered

High-throughput method for ear phenotyping and kernel weight estimation in maize using ear digital imaging (vol 14, pg 49, 2018)

After the publication of our article [1], it was brought to our attention that in six places in the article we omitted to use quotation marks to show where the text has been directly used from the cited references

High-throughput method for ear phenotyping and kernel weight estimation in maize using ear digital imaging

Abstract Background Grain yield, ear and kernel attributes can assist to understand the performance of maize plant under different environmental conditions and can be used in the variety development process to address farmer’s preferences. These parameters are however still laborious and expensive to measure. Results A low-cost ear digital imaging method was developed that provides estimates of ear and kernel attributes i.e., ear number and size, kernel number and size as well as kernel weight from photos of ears harvested from field trial plots. The image processing method uses a script that runs in a batch mode on ImageJ; an open source software. Kernel weight was estimated using the total kernel number derived from the number of kernels visible on the image and the average kernel size. Data showed a good agreement in terms of accuracy and precision between ground truth measurements and data generated through image processing. Broad-sense heritability of the estimated parameters was in the range or higher than that for measured grain weight. Limitation of the method for kernel weight estimation is discussed. Conclusion The method developed in this work provides an opportunity to significantly reduce the cost of selection in the breeding process, especially for resource constrained crop improvement programs and can be used to learn more about the genetic bases of grain yield determinants

Child Health, Agriculture and Integrated Nutrition (CHAIN): protocol for a randomised controlled trial of improved infant and young child feeding in rural Zimbabwe.

INTRODUCTION: Over one-quarter of children in sub-Saharan Africa are stunted; however, commercial supplements only partially meet child nutrient requirements, cannot be sustainably produced, and do not resolve physiological barriers to adequate nutrition (eg, inflammation, microbiome dysbiosis and metabolic dysfunction). Redesigning current infant and young child feeding (IYCF) interventions using locally available foods to improve intake, uptake and utilisation of nutrients could ameliorate underlying pathogenic pathways and improve infant growth during the critical period of complementary feeding, to reduce the global burden of stunting. METHODS AND ANALYSIS: Child Health Agriculture Integrated Nutrition is an open-label, individual household randomised trial comparing the effects of IYCF versus 'IYCF-plus' on nutrient intake during infancy. The IYCF intervention comprises behaviour change modules to promote infant nutrition delivered by community health workers, plus small-quantity lipid-based nutrient supplements from 6 to 12 months of age which previously reduced stunting at 18 months of age by ~20% in rural Zimbabwe. The 'IYCF-plus' intervention provides these components plus powdered NUA-45 biofortified sugar beans, whole egg powder, moringa leaf powder and provitamin A maize. The trial will enrol 192 infants between 5 and 6 months of age in Shurugwi district, Zimbabwe. Research nurses will collect data plus blood, urine and stool samples at baseline (5-6 months of age) and endline (9-11 months of age). The primary outcome is energy intake, measured by multipass 24-hour dietary recall at 9-11 months of age. Secondary outcomes include nutrient intake, anthropometry and haemoglobin concentration. Nested laboratory substudies will evaluate the gut microbiome, environmental enteric dysfunction, metabolic phenotypes and innate immune function. Qualitative substudies will explore the acceptability and feasibility of the IYCF-plus intervention among participants and community stakeholders, and the effects of migration on food production and consumption. ETHICS AND DISSEMINATION: This trial is registered at ClinicalTrials.gov (NCT04874688) and was approved by the Medical Research Council of Zimbabwe (MRCZ/A/2679) with the final version 1.4 approved on 20 August 2021, following additional amendments. Dissemination of trial results will be conducted through the Community Engagement Advisory Board in the study district and through national-level platforms. TRIAL REGISTRATION NUMBER: NCT04874688

Chronic cough in primary health care attendees, Harare, Zimbabwe: diagnosis and impact of HIV infection.

BACKGROUND: Cough lasting for > or = 3 weeks (i.e., chronic cough) indicates that a patient has suspected tuberculosis (TB). At the primary health care level, the spectrum of disease that causes chronic cough has not been previously investigated in a setting with a high prevalence of human immunodeficiency virus (HIV) infection. METHODS: A total of 544 adults with chronic cough were recruited systematically from 2 primary health care clinics, and they were evaluated using preset first- and second-line investigations and diagnostic case definitions. RESULTS: The overall prevalence of HIV infection among the study cohort was 83%. TB was the most common diagnosis, with 207 HIV-positive patients (46%) and 27 HIV-negative patients (30%) having confirmed or probable TB. Of these, 145 HIV-positive patients with TB (70%) and 20 HIV-negative patients with TB (74%) had smear-positive cases of TB. Only 17 HIV-positive and 2 HIV-negative patients had smear-negative but culture-positive cases of TB. Lower respiratory tract infections (n = 178; HIV prevalence, 79%) and pneumonia (n = 87; HIV prevalence, 89%) were the next most common diagnoses. Asthma (n = 26; HIV prevalence, 46%), posttuberculous disease and other fibrotic lung disease (n = 34; HIV prevalence, 88%), and cardiac disease (n = 15; HIV prevalence, 93%) were more common than were Pneumocystis jiroveci pneumonia and cryptococcosis (n = 8 and n = 5, respectively; HIV prevalence, 100%), and we found no cases of nocardiosis or histoplasmosis. CONCLUSIONS: TB was diagnosed for 43% of patients who presented with chronic cough to primary health care clinics in Harare, with 71% having smear-positive disease. The findings of TB culture added relatively little to the findings of fluorescent microscopy of concentrated sputum specimens. The prevalence of HIV infection was high across a range of diagnoses, suggesting that an HIV test should be recommended in the initial investigation of chronic cough