Evaluation of sesame (Sesamum indicum L.) varieties for drought tolerance using agromorphological traits and drought tolerance indices.

Sesame (Sesamum indicum L.) is an important cash crop cultivated under rain-fed conditions where it contributes a significant proportion of Ethiopia's foreign exchange earnings. However, its productivity is constrained by drought stress. The present study aimed to evaluate the agromorphological and yield performance of sesame varieties and to identify drought tolerant varieties using drought tolerance indices. The sesame varieties were evaluated under well-watered (WW) and water-stressed (WS) field conditions with a factorial design laid down in randomized complete block design in three replications. The results revealed the presence of a significant variation in agromorphological traits and drought tolerance indices due to water levels, varieties and their interactive effect. On average, a 21.8, 49.6, 48.4, 47.9 and 21.7% reduction was recorded in plant height, number of leaves per plant, leaf length, leaf width and relative growth rate (RGR), respectively under WS condition. Similarly, a significant reduction was found in shoot biomass, root biomass, biological yield, number of pods per plant and seed yield under WS condition. These traits showed an average reduction of 52.2, 72.5, 54.0, 51.9 and 52.8%, respectively compared to WW condition. The highest yield reduction was recorded from wollega under WS condition, while the lowest was from abasena. Wollega variety produced the highest seed yield (kg/ha) under WW condition, while gondar-1 and humera-1 had the highest yield in kg/ha under WS condition. Under both water levels, abasena produced the lowest yield (kg/ha). Moreover, gondar-1 and humera-1 varieties had a comparatively higher values of stress tolerance index (STI), yield stress score index (YSSI), yield potential score index (YPSI), geometric mean productivity (GMP) and mean productivity (MP) that are significantly and positively correlated with yield under WS, indicating higher yield performance under water stress. The biplot analysis clustered the varieties as low yielding (abasena) and relatively above average performing varieties (humera-1, gondar-1 and wollega). According to the rank sum of all indices, humera-1 was identified as drought tolerant, while abasena as the most susceptible and low yielding varieties. Thus, humera-1 followed by gondar-1 were found to be drought tolerant and high yielding varieties. However, further studies focusing on drought tolerance mechanisms of the varieties are recommended.

Land use and land cover changes and their impact on ecosystem service values in the north-eastern highlands of Ethiopia.

The land use and land cover (LULC) changes driven by the growing demands of mankind have a considerable effect on ecosystem services and functions. The study was carried out in the north-eastern highlands of Ethiopia to (1) analyze the effect of LULC changes between 1984 and 2021 and (2) assess the spatiotemporal variations in ecosystem service values (ESVs) and elasticity in response to LULC changes. Using Landsat imageries from 1984 to 2021, the spatiotemporal changes in LULC were evaluated with supervised image classification using maximum likelihood algorithm in ArcGIS software. Six LULC types were subsequently categorized, with overall accuracy and Kappa coefficients above 87% and 0.87, respectively. The ESVs were then estimated based on the Benefit Value Transfer (BVT) approach employing modified conservative value coefficients. The findings revealed a significant increase in cultivated land (9759.1ha) and built-up area (10174.41ha) during the stipulated periods and a drop in other land use types. The forest loss gradually decreased from 4.1% in the second period (1991-2001) to 0.58% in the third (2001-2021), compared to the first of the 1.1% conversion rates. Similarly, the proportion of grassland and water bodies steadily reduced over the stipulated periods, by 1.15% and 2.3% per annum, respectively. The overall loss of ESVs in the study landscape was estimated to be 54.4 million US$ (67.3%), drastically decreasing from 80.3 million US$ in 1984 to 26.4 million US$ in 2021, driven by the declining area coverage of water bodies, grassland, and forestland. Regardless of the loss, the ecosystem functions of hydrological regulation (37.2, 35.0, 6.1, and 5.1 US$ ha-1yr-1), water supply (14.5, 13.6, 2.4, and 2 US$ ha-1yr-1), and food production (9.8, 10.0, 9.1, and 9.9 US$ ha-1yr-1) contributed the most to the total ESV of each year while disturbance regulation and cultural values were the least throughout the study periods. The coefficient of sensitivity (CS) analysis revealed that our estimates were relatively robust. The findings further showed that human-dominated land-uses at the expense of natural ecosystems are the primary drivers of LULC transitions and the ensuing loss of ecosystem services in the region. Thus, this calls for intensive work on more effective land use policies that encourage an integrated management approach, with a focus on safeguarding the sustainability of natural ecosystems.

COVID-19 lockdown and natural resources: a global assessment on the challenges, opportunities, and the way forward.

BACKGROUND: The Coronavirus (COVID-19) is a global pandemic caused by SARS-CoV-2, which has an enormous effect on human lives and the global environment. This review aimed to assess the global scientific evidence on the impact of COVID-19 lockdown on natural resources using international databases and search engines. Thus, the unprecedented anthropause due to COVID-19 has positive and negative effects on natural resources. MAIN BODY: This review showed that the unprecedented pandemic lockdown events brought a negative impact on the physical environment, including pollution associated with a drastic increase in person protective equipment, deforestation, illegal poaching and logging, overfishing, disruption of the conservation program and projects. It is noted that the spread of pandemic diseases could be aggravated by environmental pollution and a rapid increase in the global population. Despite these negative impacts of COVID-19, the anthropause appear to have also several positive effects on natural resources such as short term reduction of indoor and outdoor environmental pollutants (PM2.5, PM10, NO2, SO2, CO, and CO2), reduction in noise pollutions from ships, boats, vehicles, and planes which have positive effects on aquatic ecosystems, water quality, birds behaviour, wildlife biodiversity, and ecosystem restoration. CONCLUSION: Therefore, governments and scientific communities across the globe have called for a green recovery to COVID-19 and implement multi-actor interventions and environmentally friendly technologies to improve and safeguard sustainable environmental and biodiversity management and halt the next pandemic.

Ensete ventricosum: A Multipurpose Crop against Hunger in Ethiopia.

Ensete ventricosum is a traditional multipurpose crop mainly used as a staple/co-staple food for over 20 million people in Ethiopia. Despite this, scientific information about the crop is scarce. Three types of food, viz., Kocho (fermented product from scraped pseudostem and grated corm), Bulla (dehydrated juice), and Amicho (boiled corm) can be prepared from enset. These products are particularly rich in carbohydrates, minerals, fibres, and phenolics, but poor in proteins. Such meals are usually served with meat and cheese to supplement proteins. As a food crop, it has useful attributes such as foods can be stored for long time, grows in wide range of environments, produces high yield per unit area, and tolerates drought. It has an irreplaceable role as a feed for animals. Enset starch is found to have higher or comparable quality to potato and maize starch and widely used as a tablet binder and disintegrant and also in pharmaceutical gelling, drug loading, and release processes. Moreover, enset shows high genetic diversity within a population which in turn renders resilience and food security against the ever-changing environmental factors and land use dynamics. Therefore, more research attention and funding should be given to magnify and make wider use of the crop.

Antibacterial activity of medicinal plant extracts against Ralstonia solanacearum (Smith) that causes bacterial wilt in hot pepper (Capsicum annuum L. )

This study was conducted to evaluate the in vitro antibacterial activity of some medicinal plants against Ralstonia solanacearum. Bioactive chemicals were extracted from Burcea antidysenterica, Eucalyptus citriodora, Justicia schimperiana, Lantana camara, Melia azedarach and Ricinus communis leaves using maceration method. The bioassay was evaluated by disc diffusion method. The pathogen was isolated from infected Capsicum annuum plants using Casamino acid-Peptone-Glucose agar (CPG) medium. The isolate was identified using cultural, biochemical characteristics, pathogenicity test and found to be R. solanacearum. The methanol extracts had different composition, percentage extract yield, antibacterial activity and relative percentage inhibition. Unlike others, extracts of E. citriodora and R. communis consisted of all the tested secondary metabolites. All species showed antibacterial activity except M. azedarach. Significant differences were recorded in antibacterial activity among species and test concentrations. The highest antibacterial activity and the lowest bacteriostatic and bactericidal concentrations were found from E. citriodora and R. communis extracts. The higher potency of E. citriodora and R. communis extracts suggested the potential of the two species as a biocide to control bacterial wilt. However, further in vivo studies on these species extracts are compulsory.