70 research outputs found

    Diversity of the Rice Blast Pathogen Populations in Ghana and Strategies for Resistance Management

    Get PDF
    The present study describes the outputs of a collaborative research programme funded by the UK`s Department for International Development-Crop Protection Program to investigate the genetic (lineages) and pathogenic (pathotypes) diversity of the blast fungus populations and characterize the key sites suitable for resistance screening. Seventy-one Magnaporthe grisae isolates were collected from seven regions where rice is grown, representing blast populations in Ghana. Following molecular characterization, these isolates were grouped into four distinct lineages designated as GH-1, GH-2, GH-3 and GH-4 and 25 pathotypes. GH-1 was the major lineage comprising 52% of all the isolates and was present across the country on up to 24 rice cultivars. GH-2 comprising of 30% of the isolates sampled was restricted in distribution mainly from Hohoe area on up to seven cultivars. GH-3 consisted of six isolates from Western, Eastern and Central Regions while GH-4 consisted of two isolates from Nyankpala in Northern Region. Occurrence of blast pathogen on wild rice and weed hosts has been observed and their potential impact needs to be considered in blast/weed management. Baseline data new to Ghana on the diversity and distribution pattern of the blast pathogen populations have been established and key sites identified. Adaptive research is continuing to develop technologies suitable for long-term pathogen monitoring, identify sources of resistance and develop appropriate blast management strategies

    MAXIMUM LIKELIHOOD ALGORITHM DETECTS COASTAL WETLAND CHANGES IN TWO CONTRASTING COASTAL WETLANDS IN LOUISIANA

    Get PDF
    Louisiana coastal wetlands contain about 37 percent of the estuarine herbaceous marshes in the conterminous United States. However, the combined effect of sea level rise and other anthropogenic factors have altered land use land cover over the last few years. This is true for two wetlands in coastal Louisiana, Barataria bay and Wax Lake delta. Barataria Bay, Louisiana, USA has experienced significant land loss. Updated information on the dynamics of change in these wetlands is limited and poorly documented. This information is necessary to develop strategies that will contribute to reversing and halting degradation. Thus, this study employed the Maximum Likelihood classifier on Landsat satellite imagery to assess land use and land cover changes in Barataria Bay and Wax Lake Delta, southeastern Louisiana, USA. The analysis revealed notable alterations in the land cover patterns over the study period. In Barataria Bay, there was a decrease in salt marsh areas with a corresponding increase in open water and Built-up area. In contrast, Wax Lake Delta demonstrated substantial land/wetland growth, with significant expansion of vegetation cover. The Maximum Likelihood classifier demonstrated high accuracy in classifying the land cover types, with an overall accuracy of 86% for Barataria Bay and 92% for Wax Lake Delta. These results highlight the effectiveness of the classifier in accurately identifying and mapping land cover changes in coastal environments. The findings contribute valuable insights for understanding the dynamics of coastal ecosystems and can inform decision-making processes for coastal management and conservation efforts

    A STUDY ON THE SHORELINE CHANGES AND LAND USE/LAND COVER ALONG THE KETA COASTAL ZONE

    Get PDF
    The Keta Municipality has undergone a rapid increase in population due to economic and commercial activities. This led to the municipal’s coastal and shoreline zone being faced with severe environmental challenges throughout the years. The goal of the study was to evaluate Keta’s shoreline changes and the coastal Land Use Land Cover (LULC) using multi-temporal remote sensing datasets. These datasets were subjected to the following image processing techniques such as image enhancement, image classification and, shoreline extraction. The Digital Shoreline Analysis System (DSAS), a plugin tool in ArcGIS was utilized to assess the rate of shoreline changes (i.e., erosion or accretion) from 2000 to 2020. These were achieved based on the following statistical methods used; Linear Regression Rate (LRR), Net Shoreline Movement (NSM), and End Point Rate (EPR). The LULC analysis indicated that built-up areas and water bodies have increased rapidly from 14.71–18.43%, and 47.68–50.46% respectively from 2000 to 2021. In terms of the shoreline changes, LRR showed a mean of −0.95m/year with 68.22% faced with erosion and accretion of 31.78%. The EPR and NSM revealed a mean shoreline change of −1.19m/year and −26.3/period respectively from 2000 to 2021. The EPR and NSM results both revealed that 69.24% experienced erosion and 30.76% accretion, indicating the prevalence of erosion at the shoreline. This research is to contribute to both the development of Keta’s shoreline protection and management measures as well as sustainable land use planning. Also, aids in achieving most of the Sustainable Development Goals in the municipal

    Morphological diversity and relationships among the IPGRI maize (Zea mays L) landraces held in IITA

    Get PDF
    Genetic variability estimates in maize (Zea mays L) landraces is an important information for trait improvement for food and nutrition security. Genetic diversity information in the Sub-Sahara African maize landraces is lack- ing. Agromorphological trait evaluation is a practical approach for genetic diversity estimation. Our objective was to assess genetic diversity among 60 IPGRI maize landraces held in IITA, Ibadan, against a check, «Obatanpa GH». Twenty-one quantitative traits and five qualitative traits were field-evaluated in Ghana in 2011 and 2012 wet seasons in a three-replicated randomized complete block design experiment. Large phenotypic variation was identified in all traits except cob colour, principal grain colour, and number of ears per plant. A moderate within population variation based on pooled Shannon Diversity Index was 0.68 ± 0.28. Between population variation was largest in earliness, anthesis-silking interval, and grain yield. Genetic similarity of 0.11 ± 0.00 based on squared correlation coefficient confirmed a large variability among accessions. Two major clusters, I and II, were separated on the basis of maturity characteristics, anthesis-silking interval, plant and ear heights, and grain yield. The first two principal components explained 67.89 % of the total variance. Four genotypes, TZm-1125 and TZm-1117 (5.0 Mg ha-1), TZm-1119 (5.4 Mg ha-1), and TZm-1139 (6.2 Mg ha-1) competed with the check (5.8 Mg ha-1) in grain yield. The IPGRI genotypes represent a large genetic reserve awaiting exploitation for trait improvement

    Agronomic potentials of quality protein maize hybrids developed in Ghana

    Get PDF
    A quality protein maize (QPM) hybrid programme was started in 1991 to develop and promote high and stableyielding QPM hybrids to increase production of nutritionally superior maize varieties in Ghana. Six 3- way QPM hybrids developed from inbred lines originating from germplasm of the International Centre for Maize and Wheat Improvement (CIMMYT) were evaluated on research stations and in farmers\' fields in Ghana from 1995 to 1996. In the on-station evaluations, grain yields across 10 sites in both years averaged 6.0 ton ha-1 for the three hybrids (GH132-28, GH110-5 and GH2328-88), 5.22 ton ha-1 for Obatanpa, and 3.60 ton ha-1 for the local maize variety. In farmers\' fields, data from over 50 farm sites in 1995 and 1996 showed mean yields of 4.95 ton ha-1 for the three hybrids, and 4.28 ton ha-1 for Obatanpa compared to 3.59 ton ha-1 for farmers\' varieties. On the average, the hybrids were similar to Obatanpa in days to 50 per cent silking, but were shorter in plant height and ear placement. Consumer preference tests showed that the three hybrids were rated similar to the local variety in popular traditional food preparations such as ‘kenkey\' and ‘tuo zafi\'. In 1997, the National Variety Release Committee approved the release of GH132-28, GH110-5, and GH2328-88 under the local names Dadaba, Mamaba, and CIDA-ba, respectively. These hybrids are recommended for planting in all the major agro-ecologies to boost maize production in Ghana.Les variétés de maïs hybride (Zea mays L.) dont les plus sésirées que les variétés de pollinisation libre à cause de leur uniformté et leurs potentiels de rendement plus élevés. Pour augmenter la production de variétés de maïs nutritionnellement supérieures au Ghana, I\'Institut de Recherche de Cultures a mis en place un programme hybrid de maïs protéique de qualité (MPQ) en 1991 pour développer et promouvoir des hybrides de MPQ de rendement élevés et stable. Six hybrids en trois de MPQ développés d\'issu de la même souch provenant de germeplasmes de CIMMYT (Centre International pour I\'amélioration de maïs et de blé) étaient évalués aux stations de recherches et aux champs d\'agriculteurs au Ghana de 1995 à 1996. Dans les évaluations sur place, les rendements de grain à travers 10 sites dans les deux années ont atteint la moyenne de 6.0 ton ha-1 pour les trois hybrids (GH132-28, GH110-5 et GH2328-88), 5.22 ton ha-1 pour \'Obatanpa\' et 3.60 ton ha-1 pour la variétés de maïs local. Sur les champs d\'agriculteurs des données de plus que 50 sites de champs en 1995 et 1996 montraient les rendements moyens de 4.95 ton ha-1 pour les trois hybrids et 4.28 ton ha-1 pour les \'Obatanpa\' comparées à 3.59 ton ha-1 pour les variétés d\'agriculteurs. En moyenne, les hybrides étaient semblables à \'Obatanpa\' en jours jusqu à 50% d\'apparition de soie maïs étaient plus courtes en taille de plante et en placement d\'épi. Les essais de préférence de consommateur montraient que les trios hybrides étaient évalués semblables à la variété locale dans les préparations de nouriture traditionnelle populaire telle que \'kenkey\' et \'tuo zafi\'. En 1997, le comité pour la mise en vente de Variété Nationale a approuvé la mise en vente de GH132-28, GH110-5 et GH2328-88 sous les noms locaux respectifs de Dadaba, Mamaba, et CIDA-ba. Ce hybrides sont recommandés pour la popultion dans toutes les agroéclogies majeures pour stimuler la production de maïs au Ghana. Ghana Journal of Agricultural Science Vol. 40 (1) 2007: pp. 81-8

    MAPPING FIRE SEVERITY FROM RECENT CALIFORNIA WILDFIRES USING SATELLITE IMAGERY

    Get PDF
    Urban sprawl has become a huge concern for cities like Los Angeles, New York, and Chicago in recent years. As urban sprawl pushes urbanization into city suburbs and outskirts, forest fragmentation becomes evidently prevalent and exposes forests to high temperatures, pollution, pests, and fires that threaten forest health. A 2021 report titled Rebuilding for a Resilient Recovery affirmed that the frequency and damage potential of wildfires have been exacerbated by climate change and urban sprawl especially in California. Globally, these fires can be attributed to both natural and anthropogenic drivers such as deforestation, agriculture, mining, and industrialization. Future projections predict that these incidences of fires will only worsen as the planet continues to warm further, with emphasis on the spread and intensities of the annual California wildfires over the decade. Quantifying the consequences of these fires on global climate change has become crucial and with the emergence of advanced GIS mapping tools, focus, visualization, and interpretation of fire and burn severity has become easier. However, knowledge and understanding of wildfire dynamics is limited especially in terms of fuel load, impacts on vegetation health, aerosol release and associated movement in the atmosphere. It is therefore important to address these gaps to make better and informed actions towards forest use, protection, management, and policies and broadly towards ambitious climate goals such as the UN’s Carbon Neutral goal by 2050. This study uses Sentinel 2A data from the Copernicus fleet between 2018 and 2022 to identify and assess the burn severity of affected areas in Sonoma County, California. The aim of the study is to understand the impacts of fires of fire on vegetation health and the post-fire recovery process. The Normalized Burn Ration Index (NBRI) was used to identify and measure the extent of the burnt areas within the county and their severity and Normalized Difference Vegetation Index (NDVI) was used as a measure of forest heath. The results show that Sonoma County has become a high burn severity area with a major decrease in unburned areas between 2018 and 2022. NDVI values recorded all decrease from January to December for all the years because of pre-fire season drought. The wildfire season begins in May and before then there are seasonal droughts that occur hence accounting for the initial decline in NDVI. The least values recorded were between 0.5 and 0.57 for September, indicating sparse and unhealthy vegetation because of sharp declines during the fire season

    ANALYZING THE IMPACT OF SEA LEVEL RISE ON COASTAL FLOODING AND SHORELINE CHANGES ALONG THE COAST OF LOUISIANA USING REMOTE SENSORY IMAGERY

    Get PDF
    Sea level rise poses risks to coastal areas which is increasingly rendering such areas susceptible to flood and shoreline retreat. Notably, coastal areas like Southern Louisiana located along the Gulf of Mexico has experienced endangering events of land subsidence due to flood inundations resulting from incessant distribution of hurricanes and tropical storms. This research therefore employed remote sensing data to analyze the impacts of sea level rise on coastal flooding and shoreline retreat along the coast of Louisiana. That is, by assessing Sentinel-2 imagery data to evaluate flood prone and flood extent areas particularly during the Louisiana floods and Hurricane Harvey. Based on this, the results show most of the inland parishes in coastal Louisiana such as Assumption, St. James, Livingston, Lafourche and Terrebonne were within high flood risk zones of about 9.3. These parishes also suffered severe damage in terms of affected croplands, potentially flooded areas and affected urban areas. On the other hand, most of the parishes in close proximity to the waterbodies such as the Gulf of Mexico were interestingly within low flood risk zones of about 6.1 suggesting proximity to waterbodies not being the only indicating factor of a flood prone area. This research also highlights that Louisiana's shorelines are rapidly receding at a rate that could result in the loss of one million acres of the state’s land in the next four decades. Hence, the results from this research are anticipated to contribute to sustainable shoreline setback plans and mitigative strategies to protect Louisiana's coast

    ASSESSING LAND COVER CHANGE AROUND BAYOU PEROT-LITTLE LAKE, NEW ORLEANS USING SENTINEL 2 SATELLITE IMAGERY

    Get PDF
    Global climate change has affected the rate of rising sea level, the frequency, intensity, timing, and distribution of hurricanes and tropical storms which threatens coastal ecosystems such as Bayou Perot, Little Lake in New Orleans along the Gulf of Mexico. The impact of hurricanes could include wetland and coastal land loss. This paper compared the land cover changes around Bayou-Perot- Little Lake, New Orleans, USA following Hurricanes Ida (August 26, 2021 to August 28, 2021). Two high-resolution Sentinel 2 imagery dated before and after Hurricane Ida was compared to assess the impacts of the hurricane on the land cover around Bayou Perot. A Random Forest classification (RF) algorithm in Google Earth Engine was used to produce maps and identify areas that have experienced conversions in land use or land cover change after the hurricane. This method of classification has the advantages of high classification accuracy and the ability to measure variable importance in land-cover mapping. In addition to random classification algorithm, other analysis such as the Normalized Difference Vegetation Index (NDVI) was be used to gain a better perspective of the overall changes in vegetation across the landscape. Five main classes were considered after the classification which included water, vegetation, bare soil, built up and marsh area. The results of the land cover change showed exposed old coastal marsh, valuable dune habitat providing storm protection to estuaries, wetlands, and the coastal population destroyed

    APPLICATION OF REMOTE SENSING IN MONITORING FOREST COVER CHANGE AND CARBON DIOXIDE LEVELS AT KISATCHIE NATIONAL FOREST OF LOUISIANA

    Get PDF
    It is estimated that the globe’s forest has shrunk by 3% since 1990, an area equivalence to the geographical boundaries of South Africa. The Kisatchie National Forest of Louisiana replicates plentiful climatic, physiographic and edaphic differences in the country and this forest faces a serious problem of degradation and disturbance of different nature. Remote sensing from satellites offers the best way to observe these changes over time. This study will employ Landsat-8 satellite imagery to analyze forest cover change in Kisatchie National Forest from 2010 to 2020. The objectives of the study are to (i) identify the trend, nature, and the magnitude of forest cover change, (ii) prepare image maps delineating forest cover change for the duration of the study (iii) establish the trend of CO2 levels within Kisatchie environs. Results showed a gain of forest cover within the Kisatchie National Forest which correlated to the rate of CO2 sequestration by sinks. NDVI of 2010 was 0.65 compared to 0.86 for 2020 indicating a gain of 32% of forest cover since 2010. This showed how effective Protected areas are in conserving forest cover and restricting land uses that may disturb forest structure

    THE INTEGRATION OF REMOTE SENSING AND GEOGRAPHIC INFORMATION SYSTEM (GIS) IN MANAGING URBAN ECOSYSTEMS

    Get PDF
    Urban ecosystems face numerous challenges due to rapid urbanization and population growth. Effective management of these ecosystems is crucial to ensure their sustainability and the well-being of urban residents. Remote sensing (RS) and Geographic Information Systems (GIS) have emerged as valuable tools for understanding and managing urban ecosystems. The integration of remote sensing and GIS technologies facilitate the monitoring and assessment of urban biodiversity, aiding in the conservation and restoration of ecological habitats. With this mind, the objective of this study was to investigate the integration of remote sensing and GIS technologies for real-time monitoring and assessment of environmental parameters in urban ecosystems, and their role in supporting sustainable urban ecosystem conservation efforts. Landsat 8 Operational Land Imager (OLI) images were acquired between January 2nd and April 5th 2020 to assess and monitor the dynamics in urban ecosystems in Abidjan, Accra, and Lagos. The Normalized Difference Built-up index was used to detect areas covered with concrete structures and impervious surfaces, while the Normalized Difference Vegetation Index and Normalized Difference Water Index were used to detect areas covered with vegetation and water bodies, respectively. Results of the study show that Abidjan, Accra, and Lagos experienced increased built-up areas at the expense of other land uses such as forests. Remote Sensing and GIS technologies provide valuable insights into the spatial and temporal dynamics of urban environments, supporting evidence-based decision-making and sustainable urban planning and development
    • …
    corecore