In vitro Production of Virus-Free Sweet Potato [Ipomoea batatas (L.) Lam] by Meristem Culture and Thermotherapy

Viral disease is the major factor causing significant yield loss in sweet potato. Production of disease-free clones by tissue culture technique increases yield and income of farmers. Meristems from three varieties of sweet potato were cultured at different combinations of BAP, GA3 and NAA in MS basal medium. Among the combinations, 1 mg/l BAP and 1 mg/l GA3 with 0.01 mg/l NAA resulted in 66.67% shoot induction for Awassa-83 and Guntute while 63.33% shoot induction was obtained using 1 mg/l BAP, 2 mg/l GA3 and 0.01 mg/l NAA for Awassa local. There was 100% sweet potato virus elimination from all the three varieties by meristem culture as observed by using NCM-ELISA technique. Shoot thermotherapy was done for Awassa-83 and Awassa local at 37°C for 31 days and 88.89% and 100% SPFMV and SPCSV virus elimination was achieved for the two varieties, respectively. Best shoot multiplication was obtained in MS medium containing 2 mg/l BAP for Awassa-83 (5.26 ± 0.02 shoots/explant) and Awassa local (5.12 ± 0.02 shoots/explant). For Guntute it was 2.48 ± 0.03 shoots/explant on 3 mg/l BAP. The best root length was 9.5 ± 0.10 cm, 9.68 ± 0.02 cm, and 11.03 ± 0.02 cm for Awassa-83, Awassa local and Guntute, respectively on growth regulators free ½ MS medium. The highest number of roots per shoot (6.34 ± 0.01) was obtained from Awassa-83 on 0.1 mg/l IBA. Acclimatizations were 100%, 91.11% and 90.10% for Guntute, Awassa-83 and Awassa local, respectively. This work indicates the practical applicability of plant tissue culture using meristem culture and thermotherapy to produce virus-free planting materials of sweet potato

Analysis of the Design of Grade 9 Listening Lessons in the Student’s Book and Teacher's Guide of English for Ethiopia

The study was conducted to examine the design of the listening lessons in the Grade 9 English for Ethiopia. The objective of the study was to see how the listening lessons were presented to identify if there were problems related to the design. The study employed a descriptive research design using both qualitative and quantitative approaches. It used content analysis as data gathering tool, where both the Student Textbook and the Teacher's Guide were analyzed based on the checklist adapted from NCLRC (2004) and Lingzhu (2008). The findings of the study have shown that the three stages of listening were not properly addressed in the materials evaluated, with the exclusion of the pre-listening activities in the majority of the listening lessons and the post-listening stage was missing in the majority of cases. The finding also showed that the input sources and the text types were not proportionally treated in the Textbook evaluated and the activities are comprehension exercises dominated, giving little attention to the other listening sub- skills. Hence, the study recommended that if the listening skill has to be taught effectively and the listening proficiency has to be properly addressed, the design of the listening lessons have to be reconsidered

Practices in the Teaching of Listening in Grade 9 EFL Classrooms of Mote Secondary School

This study was designed to examine the practices in the teaching of listening in Grade 9 EFL classrooms of Mote Secondary School. The study employed a descriptive survey design to attain the objective. The research used 108 Grade 9 students and 6 English language teachers who were teaching English as subjects of the study. To gather proper data for the study, questionnaire (both for students and teachers) and classroom observations were used. The data collected through questionnaire and classroom observations were analyzed both quantitatively and qualitatively. The findings of the study indicated that the teaching of listening in EFL classrooms (and that of English language teaching in general) is at a critical risk since teachers do not use the pre-listening, the while-listening and the post-listening activities to promote and facilitate the development of listening comprehension and because they never adapt or adopt activities which help students learn the skill effectively. Hence, the study recommended that an intensive training on classroom teaching and on the teaching materials which are currently in use are required for EFL teachers

Laboratory-based efficacy evaluation of; Bacillus thuringiensis; var. israelensis and temephos larvicides against larvae of; Anopheles stephensi; in Ethiopia

BACKGROUND: Malaria, transmitted by the bite of infective female Anopheles mosquitoes, remains a global public health problem. The presence of an invasive Anopheles stephensi, capable of transmitting Plasmodium vivax and Plasmodium falciparum parasites was first reported in Ethiopia in 2016. The ecology of An. stephensi is different from that of Anopheles arabiensis, the primary Ethiopian malaria vector, and this suggests that alternative control strategies may be necessary. Larviciding may be an effective alternative strategy, but there is limited information on the susceptibility of Ethiopian An. stephensi to common larvicides. This study aimed to evaluate the efficacy of temephos and Bacillus thuringiensis var. israelensis (Bti) larvicides against larvae of invasive An. stephensi. METHODS: The diagnostic doses of two larvicides, temephos (0.25 ml/l) and Bti (0.05 mg/l) were tested in the laboratory against the immature stages (late third to early fourth stages larvae) of An. stephensi collected from the field and reared in a bio-secure insectary. Larvae were collected from two sites (Haro Adi and Awash Subuh Kilo). For each site, three hundred larvae were tested against each insecticide (as well as an untreated control), in batches of 25. The data from all replicates were pooled and descriptive statistics prepared. RESULTS: The mortality of larvae exposed to temephos was 100% for both sites. Mortality to Bti was 99.7% at Awash and 100% at Haro Adi site. CONCLUSIONS: Larvae of An. stephensi are susceptible to temephos and Bti larvicides suggesting that larviciding with these insecticides through vector control programmes may be effective against An. stephensi in these localities

Past eight-year malaria data in Gedeo zone, southern Ethiopia: trend, reporting-quality, spatiotemporal distribution, and association with socio-demographic and meteorological variables.

BACKGROUND: Informed decision making is underlined by all tiers in the health system. Poor data record system coupled with under- (over)-reporting of malaria cases affects the country's malaria elimination activities. Thus, malaria data at health facilities and health offices are important particularly to monitor and evaluate the elimination progresses. This study was intended to assess overall reported malaria cases, reporting quality, spatiotemporal trends and factors associated in Gedeo zone, South Ethiopia. METHODS: Past 8 years retrospective data stored in 17 health centers and 5 district health offices in Gedeo Zone, South Ethiopia were extracted. Malaria cases data at each health center with sociodemographic information, between January 2012 and December 2019, were included. Meteorological data were obtained from the national meteorology agency of Ethiopia. The data were analyzed using Stata 13. RESULTS: A total of 485,414 suspected cases were examined for malaria during the previous 8 years at health centers. Of these suspects, 57,228 (11.79%) were confirmed malaria cases with an overall decline during the 8-year period. We noted that 3758 suspected cases and 467 confirmed malaria cases were not captured at the health offices. Based on the health centers records, the proportions of Plasmodium falciparum (49.74%) and P. vivax (47.59%) infection were nearly equivalent (p = 0.795). The former was higher at low altitudes while the latter was higher at higher altitudes. The over 15 years of age group accounted for 11.47% of confirmed malaria cases (p < 0.001). There was high spatiotemporal variation: the highest case record was during Belg (12.52%) and in Dilla town (18,150, 13.17%, p < 0.001) which is located at low altitude. Monthly rainfall and minimum temperature exhibited strong associations with confirmed malaria cases. CONCLUSION: A notable overall decline in malaria cases was observed during the eight-year period. Both P. falciparum and P. vivax were found at equivalent endemicity level; hence control measures should continue targeting both species. The noticed under reporting, the high malaria burden in urban settings, low altitudes and Belg season need spatiotemporal consideration by the elimination program

The role of grass volatiles on oviposition site selection by Anopheles arabiensis and Anopheles coluzzii

Background: The reproductive success and population dynamics, of Anopheles malaria mosquitoes is strongly influenced by the oviposition site selection of gravid females. Mosquitoes select oviposition sites at different spatial scales, starting with selecting a habitat in which to search. This study utilizes the association of larval abundance in the field with natural breeding habitats, dominated by various types of wild grasses, as a proxy for oviposition site selection by gravid mosquitoes. Moreover, the role of olfactory cues emanating from these habitats in the attraction and oviposition stimulation of females was analysed. Methods: The density of Anopheles larvae in breeding sites associated with Echinochloa pyramidalis, Echinochloa stagnina, Typha latifolia and Cyperus papyrus, was sampled and the larvae identified to species level. Headspace volatile extracts of the grasses were collected and used to assess behavioural attraction and oviposition stimulation of gravid Anopheles arabiensis and Anopheles coluzzii mosquitoes in wind tunnel and two-choice oviposition assays, respectively. The ability of the mosquitoes to differentiate among the grass volatile extracts was tested in multi-choice tent assays. Results: Anopheles arabiensis larvae were the most abundant species found in the various grass-associated habitats. The larval densities described a hierarchical distribution, with Poaceae (Echinochloa pyramidalis and Echinochloa stagnina)-associated habitat sites demonstrating higher densities than that of Typha-associated sites, and where larvae were absent from Cyperus-associated sites. This hierarchy was maintained by gravid An. arabiensis and An. coluzzii mosquitoes in attraction, oviposition and multi-choice assays to grass volatile extracts. Conclusions: The demonstrated hierarchical preference of gravid An. coluzzii and An. arabiensis for grass volatiles indicates that vegetation cues associated with larval habitats are instrumental in the oviposition site choice of the malaria mosquitoes. Identifying volatile cues from grasses that modulate gravid malaria mosquito behaviours has distinct potential for the development of tools to be used in future monitoring and control methods

A Model for the Development of the Rhizobial and Arbuscular Mycorrhizal Symbioses in Legumes and Its Use to Understand the Roles of Ethylene in the Establishment of these two Symbioses

We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis–outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants