Genetics and Genomics Commons^™

Growing Space Management In Boreal Mixedwood Forests: 22 Year Results, Richard Kabzems, George Harper, Che Elkin

Aspen Bibliography

Boreal mixed forests of trembling aspen (Populus tremuloides) and white spruce (Picea glauca) can provide higher outputs of many ecosystem goods and services, combined with resilience for changing environmental conditions. In this study, we examine the growth of white spruce and aspen over a range of stand compositions created by spot and broadcast treatments of broadleaves using manual and chemical means, aspen spacing, and untreated control. Twenty-two growing seasons postharvest, treatment responses created a range of broadleaf densities and spatial arrangements, reflected in significant differences in heights and diameters of the spruce mixedwood component. At this …

Recovery Of Trembling Aspen, Tamarack, And White Spruce Seedlings From Nacl Stress Following Winter Dormancy: Implications For Increased Foliar Potassium, Necrosis, And Sodium Management As Stress Resistance Mechanisms, Nathan T. Lauer

Aspen Bibliography

Revegetation of boreal forest lands disturbed by surface mining for bitumen can be challenging due to fluctuating levels of soil NaCl and harsh winter temperatures. These stressors may hinder the growth and survival of planted tree seedlings. Two experiments were carried out to examine the processes of recovery from NaCl stress and overwintering in trembling aspen, tamarack, and white spruce seedlings. In the recovery experiment, seedlings were treated with 0, 50, or 100 mM NaCl for 60 days and then allowed to recover for 60 days. Most of the examined physiological variables (total dry weight, chlorophyll concentration, photosynthesis, and transpiration) …

Clearing The Air Between Methane And Commercial Beef Cattle In Ireland, Clodagh V. Ryan

ORBioM (Open Research BioSciences Meeting)

Background

Rumen methanogenesis is the single most significant source of anthropogenic methane (CH₄) emissions. This research aimed to analyse CH₄ data recorded by GreenFeed systems by assessing the repeatability of such phenotypic measures, estimating the heritability of CH₄, and generating CH₄ estimated breeding values (EBVs) for inclusion in the national breeding index_.

Methods

CH₄ measurements were recorded on 979 cattle for 20 to 83 days using GreenFeed machines, resulting in 211,136 individual CH₄ observations. The phenotypic repeatability of CH₄ was estimated for six different averaging periods using a linear mixed …

Compensatory Phenolic Induction Dynamics In Aspen After Aphid Infestation, Rajarshi Kumar Gaur, Ilka Nacif De Abreu, Benedicte Riber Albrectsen

Aspen Bibliography

Condensed tannins (CTs) are polyphenolics and part of the total phenolic (TP) pool that shape resistance in aspen (Populus tremula). CTs are negatively associated with pathogens, but their resistance properties against herbivores are less understood. CTs shape resistance to pathogens and chewing herbivores and could also shape resistance to aphids. Being chemical pools that are highly variable it can further be questioned whether CT-shaped resistance is better described by constitutive levels, by the induced response potential, or by both. Here, aspen genotypes were propagated and selected to represent a range of inherent abilities to produce and store foliar …

Young Forests And Fire: Using Lidar–Imagery Fusion To Explore Fuels And Burn Severity In A Subalpine Forest Reburn, Kristin H. Braziunas, Diane C. Abendroth, Monica G. Turner

Aspen Bibliography

Anticipating fire behavior as climate change and fire activity accelerate is an increasingly pressing management challenge in fire-prone landscapes. In subalpine forests adapted to infrequent, stand-replacing fire, self-limitation of burn severity in short-interval fire is incompletely understood. Spatially explicit fuels data can support assessments of landscape-scale fire risk and fuel feedbacks on burn severity. For a ~1450-km² largely forested landscape in the US Northern Rocky Mountains, we used airborne lidar and imagery to predict and map canopy and surface fuels. In a fire that burned mature (>125-year-old) and also reburned young (~30-year-old) subalpine forest, we then asked: (1) …

Oystershell Scale: An Invasive Threat To Aspen Conservation, Amanda M. Grady, Connor D. Crouch, Nicholas P. Wilhelmi, Richard W. Hofstetter, Kristen M. Waring

Aspen Bibliography

Aspen decline is an acute and chronic problem in Arizona, where high levels of overstory mortality and a lack of recruitment continue to be observed. Oystershell scale (Lepidosaphes ulmi; OSS), an invasive sapsucking insect, has recently become widespread in native aspen stands in the southwestern U.S., further contributing to aspen mortality. Damage is severe in lower elevation stands and within ungulate exclosures created to conserve aspen. Young recruiting aspen that are rare on the landscape incur high levels of OSS-caused mortality when infested (Fig. 1). OSS has only recently become a pest of concern in the Southwest and …

Exploration Of Genes Controlling Grain Yield Heterosis In Hybrid Wheat (Triticum Aestivum L.) Utilizing 3ʹ Rna Sequencing, Nichole Lynn Miller

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The implementation and future success of hybrid wheat (Triticum aestivum L.) is impacted by breeders’ inability to create consistent high yielding, high heterosis hybrids. This research addresses this problem by conducting an exploration of transcriptomes from hybrids and parent lines to determine what genes are active in heterotic or non-heterotic hybrids and how their level of expression can explain the phenotype of grain yield heterosis. Using hybrids that showed positive mid-parent heterosis (MPH), classified as heterotic in our study, and negative or no difference MPH hybrids, classified as non-heterotic, differentially expressed genes (DEGs) potentially related to heterosis and hybrid …

Unraveling The Genetic Architecture Of Somatic Embryogenesis In Upland Cotton, Adam M. Canal

All Theses

Somatic embryogenesis is the de novo development of asexual embryos because of the plasticity of the plant cell. In tissue culture, the biochemical and genetic mechanisms of dedifferentiated callus tissues can be reprogrammed to transdifferentiate into developed, polarized embryos, which can ultimately regenerate into whole plants. Although this rarely occurs in nature, scientists have exploited this process for decades to regenerate whole plants following gene transformation or for micropropagation. While some species are amenable to in vitro regeneration, upland cotton is particularly recalcitrant, with regenerative potential being confined to only several genotypes. The lack of elite, regenerable genotypes greatly restricts …

Candidate Genes Modulating Reproductive Timing In Elite Us Soybean Lines Identified In Soybean Alleles Of Arabidopsis Flowering Orthologs With Divergent Latitude Distribution, Nicholas Dietz, Yen On Chan, Andrew Scaboo, George Graef, David Hyten, Mary Happ, Brian Diers, Aaron Lorenz, Dechun Wang, Trupti Joshi, Kristin Bilyeu

Biomedical Sciences

Adaptation of soybean cultivars to the photoperiod in which they are grown is critical for optimizing plant yield. However, despite its importance, only the major loci conferring variation in flowering time and maturity of US soybean have been isolated. By contrast, over 200 genes contributing to floral induction in the model organism Arabidopsis thaliana have been described. In this work, putative alleles of a library of soybean orthologs of these Arabidopsis flowering genes were tested for their latitudinal distribution among elite US soybean lines developed in the United States. Furthermore, variants comprising the alleles of genes with significant differences in …

Emulating Succession Of Boreal Mixedwood Forests In Alberta Using Understory Protection Harvesting, Ivan Bjelnanovic, Philip G. Comeau, Sharon Meredith, Brian Roth

Aspen Bibliography

Understory protection harvesting is a form of partial cutting that can be used in aspen (Populus tremuloides Michx.)-dominated stands that have understories of white spruce (Picea glauca (Moench) Voss). This practice involves removing 75% to 85% of the merchantable aspen while minimizing damage to the advance spruce regeneration, in addition to leaving 15% to 25% of the aspen standing to reduce potential windthrow of the spruce understory. In this paper, we summarize results from 18 stands measured 10 to 12 years after understory protection harvest. Diameter growth of spruce increased during the first five years after harvest while …

Climate Effects On Black Spruce And Trembling Aspen Productivity In Natural Origin Mixed Stands, Mahadev Sharma

Aspen Bibliography

Forest managers need site productivity estimates for tree species growing in mixed stands. Models developed in the past are generally for pure stands and don’t factor in the effects of climate change on site productivity. Therefore, site index (SI) models were developed for black spruce (Picea mariana Mill. B.S.P.) and trembling aspen (Populus tremuloides Michx.) trees grown in natural origin mixed stands. For this, 186 trees (93 black spruce and trembling aspen each) were sampled from 31 even-aged natural mixed stands (sites) (3 trees/species/site) across Ontario, Canada. Stand height growth models were developed by incorporating climate variables during …

Facilitation Differentially Affects Competitive Responses Of Aspen And Subalpine Fir Through Stages Of Stand Development, Rebecca Lee Molinari, Matthew F. Bekker, Benjamin D. St. Clair, Jason Bartholomew, R. Justin Derose, Stanley G. Kitchen, Samuel B. St. Clair

Aspen Bibliography

Spatial interactions between trees influence forest community succession. The objective of this study was to investigate how shifts in forest composition and proximity between tree species affect stand development over time in mixed forest systems. At six locations across the Fishlake National Forest, Utah, USA, in stands where facilitation has been documented previously, tree-ring samples were collected from aspen and subalpine fir trees. Basal area increment was calculated to characterize the effects of the proximity of overstory trees on multidecadal growth responses of aspen and subalpine fir in aspen-dominant and mixed aspen–conifer stands. Subalpine fir seedlings were established next to …

Bottom-Up Drivers Of Future Fire Regimes In Western Boreal North America, Adrianna C. Foster, Jacquelyn K. Shuman, Brendan M. Rogers, Xanthe J. Walker, Michelle C. Mack, Laura L. Bourgeau-Chavez, Sander Veraverbeke, Scott J. Goetz

Aspen Bibliography

Forest characteristics, structure, and dynamics within the North American boreal region are heavily influenced by wildfire intensity, severity, and frequency. Increasing temperatures are likely to result in drier conditions and longer fire seasons, potentially leading to more intense and frequent fires. However, an increase in deciduous forest cover is also predicted across the region, potentially decreasing flammability. In this study, we use an individual tree-based forest model to test bottom-up (i.e. fuels) vs top-down (i.e. climate) controls on fire activity and project future forest and wildfire dynamics. The University of Virginia Forest Model Enhanced is an individual tree-based forest model …

Identifying Conifer Tree Vs. Deciduous Shrub And Tree Regeneration Trajectories In A Space-For-Time Boreal Peatland Fire Chronosequence Using Multispectral Lidar, Humaira Enayetullah, Laura Chasmer, Christopher Hopkinson, Dan Thompson, Danielle Cobbaert

Aspen Bibliography

Wildland fires and anthropogenic disturbances can cause changes in vegetation species composition and structure in boreal peatlands. These could potentially alter regeneration trajectories following severe fire or through cumulative impacts of climate-mediated drying, fire, and/or anthropogenic disturbance. We used lidar-derived point cloud metrics, and site-specific locational attributes to assess trajectories of post-disturbance vegetation regeneration in boreal peatlands south of Fort McMurray, Alberta, Canada using a space-for-time-chronosequence. The objectives were to (a) develop methods to identify conifer trees vs. deciduous shrubs and trees using multi-spectral lidar data, (b) quantify the proportional coverage of shrubs and trees to determine environmental conditions driving …

Use Of Heterothallic Mat Deletion Strains Of Fusarium Graminearum As Test Mates In Crosses To Evaluate The Genetics Of Pathogenicity And Fitness, Gabdiel Emmanuel Yulfo-Soto

Theses and Dissertations--Plant Pathology

Fusarium Head Blight (FHB), caused by Fusarium graminearum sensu stricto and other members of the F. graminearum species complex (FGSC), is a plant disease that occurs on cereal crops worldwide. FHB causes yield losses not only by reducing grain weight, but also by contaminating the kernels with dangerous trichothecene mycotoxins, especially deoxynivalenol (DON). There is a high degree of genotypic and phenotypic variation among pathogen species and strains, but current FHB risk assessment models and treatments do not account for pathogen diversity. Therefore, it is difficult to predict what will happen if a new, potentially more aggressive variant is introduced, …

Effects Of Buried Wood On The Development Of Populus Tremuloides On Various Oil Sands Reclamation Soils, Kaitlyn E. Trepanier, Laura Manchola-Rojas, Bradley D. Pinno

Aspen Bibliography

Buried wood is an important but understudied component of reclamation soils. We examined the impacts of buried wood amounts and species on the growth of the common reclamation tree species trembling aspen (Populus tremuloides). In a greenhouse study, aspen seedlings were planted into four soil types, upland derived fine forest floor-mineral mix (fFFMM), coarse forest floor-mineral mix (cFFMM), and lowland derived peat and peat-mineral mix (PMM), that were mixed with either aspen or pine wood shavings at four concentrations (0%, 10%, 20% and 50% of total volume). Height and diameter growth, chlorophyll concentration, and leaf and stem biomass were measured. …

A Functional Genomics Approach To Overwintering Mechanisms In Insects, Emily Allison Wheeler Nadeau

Theses and Dissertations--Entomology

Insects living in temperate and polar environments have developed numerous adaptations to increase survival at low temperatures. A majority of insects are freeze-intolerant and die from internal ice formation, but some are freeze-tolerant and can survive ice formation in extracellular spaces. Both categories of insects prepare for winter with a combination of seasonal and rapid acclimation responses, which differ both in time course and in underlying mechanisms. In this dissertation, I examine adaptations for winter survival in several insect species with a specific focus on molecular mechanisms. To better understand the underpinning mechanisms of these adaptations, I leverage functional genomics …

Analysis Of Root System Architecture And Qtl Identification In Grapevines, Sujan Thapa

Graduate Theses/Dissertations

The root system of the plant plays a vital role in water and nutrient uptake. Native North American grapevines adapted to a broad range of climatic and soil conditions, which led to the evolution of diverse root system architecture (RSA) within the Vitis genus. Despite the importance of RSA in viticulture, little is known about the genetic basis of the RSA in grapevine. I used novel root phenotyping tool, RhizoVision Analyzer to characterize the root system of 208 genotypes of an F₁ grapevine progeny obtained from a cross between Vitis rupestris Scheele B38 and Vitis riparia Michx. HP-1. Dormant …

Getting To The Root Cause: The Genetic Underpinnings Of Root System Architecture And Rhizodeposition In Sorghum, Farren Smith

Graduate Theses, Dissertations, and Problem Reports (ETD)

Plants are some of the most diverse organisms on earth, consisting of more than 350,000 different species. To understand the underlying processes that contributed to plant diversification, it is fundamental to identify the genetic and genomic components that facilitated various adaptations over evolutionary history. Most studies to date have focused on the underlying controls of above-ground traits such as grain and vegetation; however, little is known about the “hidden half” of plants. Root systems comprise half of the total plant structure and provide vital functions such as anchorage, resource acquisition, and storage of energy reserves. The execution of these key …

Modeling The Evolution Of Herbicide Resistance In Weed Species With A Complex Life Cycle, K. Harrison Holmes, John L. Lindquist, Richard Rebarber, Rodrigo Werle, Melinda K. Yerka, Brigitte Tenhumberg

Brigitte Tenhumberg Papers

A growing number of weed species have evolved resistance to herbicides in recent years, which causes an immense financial burden to farmers. An increasingly popular method of weed control is the adoption of crops that are resistant to specific herbicides, which allows farmers to apply the herbicide during the growing season without harming the crop. If such crops are planted in the presence of closely related weed species, it is possible that resistance genes could transfer from the crop species to feral populations of the wild species via gene flow and become stably introgressed under ongoing selective pressure by the …

Epinasty Accompanies Potassium Nitrate-Induced Flower Bud Break In 'Carabao' Mango [Research Note], Ulysses Besas, Calixto Protacio

The Philippine Agricultural Scientist

The hypothesis that potassium nitrate application promotes epinasty in ‘Carabao’ mango through increased ethylene production was investigated. The degree of drooping, apical primordium growth as affected by shoot ethylene and levels after potassium nitrate spraying were monitored. Evidence presented established for the first time in ‘Carabao’ mango that epinasty occurred just before flower emergence, coinciding with visible bud break, and extended up to 18 days, marking floral anthesis. The possible reasons could be the higher levels of ethylene at 0.31% and earlier increase of ethylene in the shoot apex at four hours and apical primordium growth. Increased ethylene levels at …

Sampling Bias Exaggerates A Textbook Example Of A Trophic Cascade, Elaine M. Brice, Eric J. Larsen, Daniel R. Macnulty

Aspen Bibliography

Understanding trophic cascades in terrestrial wildlife communities is a major challenge because these systems are difficult to sample properly. We show how a tradition of non-random sampling has confounded this understanding in a textbook system (Yellowstone National Park) where carnivore [Canis lupus (wolf)] recovery is associated with a trophic cascade involving changes in herbivore [Cervus canadensis (elk)] behaviour and density that promote plant regeneration. Long-term data indicate a practice of sampling only the tallest young plants overestimated regeneration of overstory aspen (Populus tremuloides) by a factor of 4–7 compared to random sampling because it favoured plants taller than the preferred …

Estimation Of Genetic Diversity Among Canola Accessions Using Simple Sequence Repeat Markers, Jaleel Ahmad, Muhammad Baber, Wajid Nazeer, Sana Hamdullah, Aleena Ahmad Somroo, Shaiza Ali, Rameen Fatima, Seema Aslam

Journal of Bioresource Management

Genetic studies through molecular markers proved important to find out the genetic diversity of canola. In this study, 50 lines of canola were used to find the polymorphism using 15 SSR primers and investigated the genetic diversity, PIC values, frequency-based genetic distance, and allelic frequencies. Mean gene diversity, frequency-based genetic distance, and PIC values were 0.8777, 0.233 and 0.8666, respectively for the canola lines. A good range of genetic diversity was found among studied canola lines with value 85.91% polymorphism. Maximum and minimum genetic distances among 50 lines were 1 and 0.26, respectively. Accessions ACC-26068, ACC-24241, ACC-24244, ACC-24233, ACC-24423 and …

Growth–Defense Trade-Offs Shape Population Genetic Composition In An Iconic Forest Tree Species, Olivia L. Cope, Ken Keefover-Ring, Eric L. Kruger, Richard L. Lindroth

Aspen Bibliography

All organisms experience fundamental conflicts between divergent metabolic processes. In plants, a pivotal conflict occurs between allocation to growth, which accelerates resource acquisition, and to defense, which protects existing tissue against herbivory. Trade-offs between growth and defense traits are not universally observed, and a central prediction of plant evolutionary ecology is that context-dependence of these trade-offs contributes to the maintenance of intraspecific variation in defense [Züst and Agrawal, Annu. Rev. Plant Biol., 68, 513–534 (2017)]. This prediction has rarely been tested, however, and the evolutionary consequences of growth–defense trade-offs in different environments are poorly understood, especially in long-lived species …

Genetic Diversity And Population Structure Of Sugarcane (Saccharum Officinarum L.) Collected From Seven Philippine Regions For Use As Breeding Stocks For Crop Improvement, Jan Leandro Acedera, Jhun Laurence Rasco, Jemimah Banganan, Antonio Lalusin

The Philippine Agricultural Scientist

Selection of parents for hybridization relies on the information on their genetic relationship and diversity which are essential in any breeding program. This study aimed to estimate the extent of genetic diversity and population structure of 76 sugarcane accessions from seven regions in the Philippines using 57 morphological characters and 50 microsatellite markers. The sugarcane collections exhibited moderate to high diversity with mean of H’ = 0.72 for qualitative and H’ = 0.75 for quantitative morphological characters, respectively. This is corroborated by the analysis of variance (ANOVA) of agronomic parameters, except for stalk length. Unweighted Pair Group Method with Arithmetic …

Determining The Novel Pathogen Neodothiora Populina As The Causal Agent Of The Aspen Running Canker Disease In Alaska, Loretta M. Winton, Gerard C. Adams, Roger W. Ruess

Aspen Bibliography

Neodothiora populina Crous, G.C. Adams & Winton was determined to be a new pathogen of trembling aspen (Populus tremuloides) growing in Alaska, based on completion of Koch’s Postulates in replicated forest and growth chamber inoculation trials. The pathogen is responsible for severe damage and widespread rapid mortality of sapling to mature aspen (≥ 80 years) in the boreal forests of interior Alaska, due to large diffuse annual (1–2 years) cankers. Isolation of the pathogen was challenging, and identification based on cultural characters was difficult. Fruiting bodies were not found on wild diseased trees, but erumpent pycnidia were found …

Marker-Assisted Selection To Determine The Introgression Of Rpv-3 Mediated Downy Mildew Resistance In 'Chambourcin' X 'Caberenet Sauvignon' Grapevine Population, Kavya Sri Tummala

Graduate Theses/Dissertations

Downy mildew caused by the fungus, Plasmopara viticola in the grapes is one of the major diseases affecting crop yield throughout the world. Breeding grapes via conventional methods for the downy mildew resistance will take approximately 25-30 years to fully evaluate and release new cultivars. Because of the long breeding cycle in woody plant species like grape, developing DNA markers linked to genes or quantitative trait loci (QTLs) for horticultural traits can greatly accelerate the breeding process and allow a much more accurate selection of progeny. This study aims to determine the presence of resistance in the 267 F1 genotypes …

Development Of High Value Oil Traits Using The Model Oilseed Crop Camelina Sativa, Evan Updike

Department of Biochemistry: Dissertations, Theses, and Student Research

Plant oils are an important source of food, fuel, and feed in our society today. The oil found in the seeds of plants is composed almost entirely of triacylglycerol (TAG) molecules, which consist of three fatty acids esterified to a glycerol backbone. As crude oil supplies decline, vegetable oils are gaining traction as a renewable substitute to petroleum-based materials in fuels, lubricants, and specialty oleochemicals. However, as it currently stands vegetable oils do not possess the properties necessary to fill the void of a petroleum free world.

To address this problem, plant biotechnologists have done extensive work on genetic engineering …

Estimation Of Breed Effects And Genetic Parameters For Age At Slaughter And Days To Finish In A Multibreed Beef Cattle Population, Lindsay Rae Upperman

Department of Animal Science: Dissertations, Theses, and Student Research

Cattle efficiency during the finishing phase is a crucial factor in determining profit in the beef cattle industry. Economically relevant traits associated with efficient production include age at slaughter (AAS) and days to finish (DtF). Selection to reduce the number of days an animal takes to reach a finish endpoint would ultimately reduce production costs, increase net profits, and result in a more sustainable production system. However, most harvested animals are from commercial herds, necessitating the use of indicator traits from seedstock animals for selection. Potential indicator traits include ultrasound measurements that could be genetically correlated to DtF traits. The …

Availability And Structure Of Coarse Woody Debris In Hemiboreal Mature To Old-Growth Aspen Stands And Its Implications For Forest Carbon Pool, Silva Šēnhofa, Guntars Šnepsts, Kārlis Bičkovskis, Ieva Jaunslaviete, Līga Liepa, Inga Straupe, Āris Jansons

Aspen Bibliography

European aspen deadwood is extensively studied as a habitat for saproxylic species, while less is known of its dynamics and role in carbon sequestration. We studied unmanaged mature (41–60 years), moderately overmature (61–80 years), overmature (81–100 years), and old-growth (101–140 years) and managed mature and moderately overmature aspen stands on fertile mineral soils. In unmanaged stands, marginal mean CWD volume was from 67.3 ± 12.1 m³ ha⁻¹ in moderately overmature to 92.4 ± 5.1 m³ ha⁻¹ in old-growth stands, with corresponding marginal mean CWD carbon pool 8.2 ± 1.6 t ha⁻¹ and 12.5 ± 0.7 …