scholarly journals Will natural resistance result in populations of ash trees remaining in British woodlands after a century of ash dieback disease?

2019 ◽  
Vol 6 (8) ◽  
pp. 190908
Author(s):  
Matthew R. Evans
Keyword(s):  
Population Size ◽  
Host Species ◽  
Natural Resistance ◽  
Ash Dieback ◽  
Pests And Diseases ◽  
Ash Trees ◽  
High Heritability ◽  
Dieback Disease ◽  
The Impact ◽  
Selective Breeding Programme

Novel pests and diseases are becoming increasingly common, and often cause additional mortality to host species in the newly contacted communities. This can alter the structure of the community up to, and including, the extinction of host species. In the last 20 years, ash dieback (ADB) disease has spread into Europe from East Asia. It has caused substantial mortality in ash tree ( Fraxinus excelsior L . ) populations. However, a proportion of the individuals in most populations appear to be less susceptible to ADB and resistance seems to have high heritability. These observations have led to suggestions that ash populations may be sustainable after the disease. In order to test this hypothesis, I modified an existing model of UK woodland (parametrized for Wytham Woods, Oxfordshire) to take into account the impact of ADB and allowed offspring to inherit resistance traits from their parent. The results suggest that ash populations would still exist in 100 years, but at lower levels than they are currently. For example, when the initial proportion of resistant individuals is about 10% and heritability of resistance is 0.5, then the population of ash falls to about one-third of present levels. The proportion of individuals initially resistant to ADB had a larger effect on population size after 100 years than the heritability of resistance. The fact that the initial size of the resistant population is important to achieve a high population size in the presence of ADB suggests that a selective breeding programme with the intention of augmenting the natural ash populations would be beneficial.

scholarly journals The impact of ash dieback on veteran trees in southwestern Sweden

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Vikki Bengtsson ◽  
Anna Stenström ◽  
C. Philip Wheater ◽  
Karin Sandberg
Keyword(s):  
Key Words ◽  
Mortality Rates ◽  
Ash Dieback ◽  
Hymenoscyphus Fraxineus ◽  
Veteran Trees ◽  
Significant Difference ◽  
Ash Trees ◽  
Dieback Disease ◽  
The Impact ◽  
First Time

Ash dieback (Hymenoscyphus fraxineus) is a fungal disease which affects ash throughout Sweden.  Monitoring to study of the impact of ash dieback on veteran trees was undertaken in southwest Sweden in 2009, 2011, 2013, 2015, and 2020. The study found that 94.5% of the ash trees observed were affected by ash dieback disease in 2020 compared with 62% in 2009.  70 of the studied ash trees have died (21%) since the monitoring began. In 2009 there was no relationship between girth and ash dieback, but in 2020 the correlation between girth and the impact of ash dieback was statistically significant. In 2020, also for the first time during monitoring, the ash trees in the shade were significantly more affected by ash dieback, compared with trees standing in the open. This difference was not detected in 2013 or 2015. The effect of ash dieback on pollarded trees has varied between the years studied, but in 2020 there is no longer any significant difference between the pollarded and the non-pollarded ash trees.  There was however a significant difference in the mortality rates between the groups of trees, with ash trees pollarded in more recent times having the highest mortality. Therefore, the recommendation in relation to veteran trees with ash dieback is that all pruning on veteran ash trees should be avoided. Pollarding should only be done on ash pollards that are in a regular cutting cycle and are not showing any symptoms of ash dieback.  If possible, clear around old ash trees if they are in shaded conditions. Given that there are relatively few studies on the impact of ash dieback on veteran ash trees, the results of this study should also be relevant outside of Sweden and for the management of ash trees in non-woodland situations. Key words: Ash dieback, pollards, veteran trees, Hymenoscyphus fraxineus, ash

scholarly journals Lessons from Fraxinus, a crowd-sourced citizen science game in genomics

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Ghanasyam Rallapalli ◽  
Diane GO Saunders ◽  
Kentaro Yoshida ◽  
Anne Edwards ◽  
Carlos A Lugo ◽  
...  
Keyword(s):  
Linear Model ◽  
Citizen Science ◽  
Ash Dieback ◽  
Science Project ◽  
Design And Implementation ◽  
Ash Trees ◽  
Dieback Disease ◽  
Genetic Sequences ◽  
Citizen Science Project ◽  
Work Done

In 2013, in response to an epidemic of ash dieback disease in England the previous year, we launched a Facebook-based game called Fraxinus to enable non-scientists to contribute to genomics studies of the pathogen that causes the disease and the ash trees that are devastated by it. Over a period of 51 weeks players were able to match computational alignments of genetic sequences in 78% of cases, and to improve them in 15% of cases. We also found that most players were only transiently interested in the game, and that the majority of the work done was performed by a small group of dedicated players. Based on our experiences we have built a linear model for the length of time that contributors are likely to donate to a crowd-sourced citizen science project. This model could serve a guide for the design and implementation of future crowd-sourced citizen science initiatives.

scholarly journals Assessing Genotypic and Environmental Effects on Endophyte Communities of Fraxinus (Ash) Using Culture Dependent and Independent DNA Sequencing

2021 ◽  
Vol 7 (7) ◽  
pp. 565
Author(s):  
Anindita Lahiri ◽  
Brian R. Murphy ◽  
Trevor R. Hodkinson
Keyword(s):  
Community Composition ◽  
Environmental Effects ◽  
High Throughput Sequencing ◽  
Fungal Community Composition ◽  
Species Identity ◽  
Ash Dieback ◽  
Hymenoscyphus Fraxineus ◽  
Culture Independent ◽  
The Impact ◽  
Culture Dependent

Fraxinus excelsior populations are in decline due to the ash dieback disease Hymenoscyphus fraxineus. It is important to understand genotypic and environmental effects on its fungal microbiome to develop disease management strategies. To do this, we used culture dependent and culture independent approaches to characterize endophyte material from contrasting ash provenances, environments, and tissues (leaves, roots, seeds). Endophytes were isolated and identified using nrITS, LSU, or tef DNA loci in the culture dependent assessments, which were mostly Ascomycota and assigned to 37 families. Few taxa were shared between roots and leaves. The culture independent approach used high throughput sequencing (HTS) of nrITS amplicons directly from plant DNA and detected 35 families. Large differences were found in OTU diversity and community composition estimated by the contrasting approaches and these data need to be combined for estimations of the core endophyte communities. Species richness and Shannon index values were highest for the leaf material and the French population. Few species were shared between seed and leaf tissue. PCoA and NMDS of the HTS data showed that seed and leaf microbiome communities were highly distinct and that there was a strong influence of Fraxinus species identity on their fungal community composition. The results will facilitate a better understanding of ash fungal ecology and are a step toward identifying microbial biocontrol systems to minimize the impact of the disease.

scholarly journals Possibilities and limits for using the gut microbiome to improve captive animal health

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Jessica Diaz ◽  
Aspen T. Reese
Keyword(s):  
Gut Microbiome ◽  
Host Species ◽  
Animal Health ◽  
Health Impacts ◽  
Wide Range ◽  
Host Health ◽  
In Captivity ◽  
Outstanding Question ◽  
The Impact ◽  
Captive Animal

AbstractBecause of its potential to modulate host health, the gut microbiome of captive animals has become an increasingly important area of research. In this paper, we review the current literature comparing the gut microbiomes of wild and captive animals, as well as experiments tracking the microbiome when animals are moved between wild and captive environments. As a whole, these studies report highly idiosyncratic results with significant differences in the effect of captivity on the gut microbiome between host species. While a few studies have analyzed the functional capacity of captive microbiomes, there has been little research directly addressing the health consequences of captive microbiomes. Therefore, the current body of literature cannot broadly answer what costs, if any, arise from having a captive microbiome in captivity. Addressing this outstanding question will be critical to determining whether it is worth pursuing microbial manipulations as a conservation tool. To stimulate the next wave of research which can tie the captive microbiome to functional and health impacts, we outline a wide range of tools that can be used to manipulate the microbiome in captivity and suggest a variety of methods for measuring the impact of such manipulation preceding therapeutic use. Altogether, we caution researchers against generalizing results between host species given the variability in gut community responses to captivity and highlight the need to understand what role the gut microbiome plays in captive animal health before putting microbiome manipulations broadly into practice.

scholarly journals Pengaruh Magnesium, Boron, dan Pupuk Hayati terhadap Produktivitas Cabai serta Serangan Hama dan Penyakit (Effect of Magnesium, Boron, and Biofertilizers on Chili Pepper Productivity and Impact of Pests and Diseases)

2020 ◽  
Vol 30 (1) ◽  
pp. 65
Author(s):  
Wiwin Setiawati ◽  
Ahsol Hasyim ◽  
Bagus Kukuh Udiarto ◽  
Abdi Hudayya
Keyword(s):  
Yield Components ◽  
Growth Parameters ◽  
Block Design ◽  
Fruit Weight ◽  
Chili Pepper ◽  
Growth And Yield ◽  
Vegetable Crops ◽  
Positive Interaction ◽  
Pests And Diseases ◽  
The Impact

<p>Penggunaan pupuk hayati dan unsur hara makro sekunder seperti magnesium (Mg) dan hara mikro boron (B) diketahui dapat meningkatkan pertumbuhan, kualitas hasil tanaman, meningkatkan unsur hara dalam tanah serta mampu meningkatkan ketahanan tanaman terhadap serangan hama dan penyakit. Selain itu penggunaan pupuk tersebut dapat mengurangi kebutuhan terhadap pupuk kimia sintetis. Tujuan penelitian adalah mengetahui pengaruh aplikasi Mg, B, dan kombinasinya dengan pupuk hayati terhadap pertumbuhan dan hasil panen serta penekanan serangan hama dan penyakit. Penelitian dilakukan di Kebun Percobaan Balai Penelitian Tanaman Sayuran, Lembang, Jawa Barat (1.250 m dpl.) dari bulan Juni 2018 sampai bulan Februari 2019. Rancangan percobaan yang digunakan adalah Rancangan Acak Kelompok terdiri atas delapan perlakuan dan empat ulangan. Perlakuan yang diuji adalah aplikasi Mg, B, dan kombinasi dengan pupuk hayati serta teknologi konvensional sebagai pembanding. Pengamatan dilakukan terhadap pertumbuhan tanaman (tinggi tanaman dan luas kanopi), komponen hasil dan hasil serta serangan hama dan penyakit penting yang menyerang tanaman cabai. Hasil penelitian menunjukkan bahwa kombinasi Mg, B, dan pupuk hayati yang diaplikasikan sebanyak dua kali pada umur 30 HST dan 45 HST mampu meningkatkan produktivitas cabai sebesar 21,68 ton/ha atau meningkat sebesar 54,53% dibandingkan dengan kontrol. Peningkatan produktivitas cabai terjadi karena adanya perbaikan dalam komponen hasil seperti jumlah bunga, jumlah buah, panjang, dan bobot buah serta adanya penekanan terhadap serangan hama dan penyakit seperti trips, antraknosa, lalat buah, dan penggerek buah sebesar 18,10% sampai 23,93%.</p><p><strong>Keywords</strong></p><p><em>Capsicum annuum</em>; Unsur hara makro; Pupuk hayati; Produktivitas; Organisme pengganggu tumbuhan</p><p><strong>Abstract</strong></p><p>The use of biofertilizer and macro and micro nutrients enhanced the growth and development, yield quality of vegetable crops as well as nutrient status of soil to a greater extent and to increased on pests and diseases resistance. Organic sources of nutrients including biofertilizers also economize the use of chemical fertilizers. The objectives of this study were to determine the best combination of Mg, B, and biofertilizer that increase the growth and yield of chili pepper and the impact to pest and diseases on chili pepper. The field experiment was conducted at the experimental field of the Indonesian Vegetable Research Institute, Lembang, West Java from June 2018 to February 2019. The experiment was arranged in a Randomized Block Design with eight treatments and four replicated. The treatments were Mg, B, and their combinations with biofertilizer compared to the conventional technologies as a control. The observations were carried out on the growth parameters (plant height and leaf canopy), yield components, pest and diseases of chili pepper. The results showed that the combinations of Mg, B, and biofertilizer increased the yield of chili up to 21.68 ton/ha or positive interaction beside beneficial agent with Mg, B, and biofertilizer package on 54.53%. Increased productivity of chili occurs because of improvements in yield components such as the number of flowers, number of fruits, fruit length and fruit weight and reduction of pest and disease attacks such as thrips, anthracnose, fruit flies and, fruit borers by 18.10% to 23.93%.</p>

scholarly journals History and impact of a bean (Phaseolus spp., Leguminosae, Phaseoleae) collection

2021 ◽  
Vol 2 (4) ◽  
pp. 21-43
Author(s):  
Daniel Debouck ◽  
Marcela Santaella ◽  
Luis Guillermo Santos
Keyword(s):  
Biological Sciences ◽  
Agricultural Development ◽  
Tropical Agriculture ◽  
Pests And Diseases ◽  
Low Phosphorus ◽  
Iron And Zinc ◽  
Per Se ◽  
Resources Conservation ◽  
The Impact ◽  
Conservation And Management

This work explains the reasons why a bean collection was established in 1973 at the International Center of Tropical Agriculture (CIAT) near Palmira in Colombia. It shows the impact of the collection on plant breeding and in agricultural development through the distribution of germplasm to the center’s bean breeding program, to successively find resistances to pests and diseases, adaptation to low phosphorus and drought, and more recently higher content of iron and zinc in seeds. The collection was also used to progress knowledge in biological sciences, as shown by a dozen of examples. A reason behind these successes was foresight and focus on diversity per se in the collection. The paper ends with a number of suggestions for the way ahead for the genetic resources conservation and management of these bean crops, and possible take-home lessons for curators in charge of other similar collections.

scholarly journals Choosing Mutation and Crossover Ratios for Genetic Algorithms—A Review with a New Dynamic Approach

Information ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 390 ◽  
Author(s):  
Ahmad Hassanat ◽  
Khalid Almohammadi ◽  
Esra’a Alkafaween ◽  
Eman Abunawas ◽  
Awni Hammouri ◽  
...  
Keyword(s):  
Population Size ◽  
Optimization Problems ◽  
Large Population ◽  
Small Population ◽  
Mutation Rates ◽  
Mutation Operators ◽  
Tuning Methods ◽  
Two Parameters ◽  
The Impact ◽  
Crossover And Mutation

Genetic algorithm (GA) is an artificial intelligence search method that uses the process of evolution and natural selection theory and is under the umbrella of evolutionary computing algorithm. It is an efficient tool for solving optimization problems. Integration among (GA) parameters is vital for successful (GA) search. Such parameters include mutation and crossover rates in addition to population that are important issues in (GA). However, each operator of GA has a special and different influence. The impact of these factors is influenced by their probabilities; it is difficult to predefine specific ratios for each parameter, particularly, mutation and crossover operators. This paper reviews various methods for choosing mutation and crossover ratios in GAs. Next, we define new deterministic control approaches for crossover and mutation rates, namely Dynamic Decreasing of high mutation ratio/dynamic increasing of low crossover ratio (DHM/ILC), and Dynamic Increasing of Low Mutation/Dynamic Decreasing of High Crossover (ILM/DHC). The dynamic nature of the proposed methods allows the ratios of both crossover and mutation operators to be changed linearly during the search progress, where (DHM/ILC) starts with 100% ratio for mutations, and 0% for crossovers. Both mutation and crossover ratios start to decrease and increase, respectively. By the end of the search process, the ratios will be 0% for mutations and 100% for crossovers. (ILM/DHC) worked the same but the other way around. The proposed approach was compared with two parameters tuning methods (predefined), namely fifty-fifty crossover/mutation ratios, and the most common approach that uses static ratios such as (0.03) mutation rates and (0.9) crossover rates. The experiments were conducted on ten Traveling Salesman Problems (TSP). The experiments showed the effectiveness of the proposed (DHM/ILC) when dealing with small population size, while the proposed (ILM/DHC) was found to be more effective when using large population size. In fact, both proposed dynamic methods outperformed the predefined methods compared in most cases tested.

scholarly journals Assessment of Equity in Access to Percutaneous Coronary Intervention (PCI) Centres in Poland

Healthcare ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 71 ◽  
Author(s):  
Justyna Rój ◽  
Maciej Jankowiak
Keyword(s):  
Percutaneous Coronary Intervention ◽  
Population Size ◽  
Gini Coefficient ◽  
Coronary Intervention ◽  
Invasive Procedures ◽  
Invasive Treatment ◽  
The Gini Coefficient ◽  
Invasive Cardiology ◽  
Percutaneous Coronary ◽  
The Impact

The purpose of this study is to analyse the disparities in the distribution of percutaneous coronary intervention (PCI) centres in Poland and the impact of eventual inequities on access to the invasive treatment of acute myocardial infarctions (AMI). To examine the distribution of PCI centres against population size and geographic size in Poland, the Gini coefficient calculated based on the Lorenz Curve was engaged. In addition, the regression function was employed to estimate the impact of distribution of PCI centres on access to invasive procedures (coronarographies and primary percutaneous coronary intervention). Data were collected from the public statistical system and Polish National Health Fund database for the year 2018. The relation and the level of equity was measured based on the aggregated data at a district (voivodeship) level. The results of the Gini coefficient analysis show that the distribution of invasive cardiology units measured against population size is more equitable than when measured against geographic size. In addition, the regression analysis shows the moderate size of the positive correlation between number of PCI centres per 100,000 population and the number of all categories of the invasive treatment of AMI per 100,000 population, and the lack of similar correlation in case of the number of PCI centres expressed per 1000 km2, which could be evidence of an insufficiency of PCI centres in areas where the concentration of PCI centres per 100,000 population is lower. The main implication for policy makers that results from this research is the need for a correction of PCI centres distribution per 100,000 inhabitants to ensure better access to invasive procedures.

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