Lessons
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A Place to Call Home
How to meet the needs of perennial plants by considering light, community, soil, air, water, and temperature.
Adaptive Cycle
This module covers the adaptive cycle, which is a conceptual model designed to help humans understand and manage how and why change occurs within common complex systems, such as ecosystems, societies, or economies. The adaptive cycle has four phases characterized by growth, stabilization, collapse, or reorganization. In this module we use the example of the Roman Empire and how its different periods can illustrate the phases of the adaptive cycle. Other examples of the adaptive cycle can be found in aquatic algal blooms, commodity crop markets, and other cultures and societies. The concept of the adaptive cycle is useful for management and decision making as an expansion on traditional ecological theory. Traditional ecological theory assumes that systems organize linearly into a single stable state that can be maintained in perpetuity despite unprecedented human change on local, regional, and global scales, which we now know is not the case in our dynamic world.
Advanced Backcross Breeding
This lesson is a detailed explanation of the backcross breeding process. Variations based on whether backcrossing is performed with dominant, recessive, or multiple traits are discussed. Calculations associated with backcross breeding are explained.
Alternative Stable State Theory and Regime Shifts
This lesson is an introduction to alternative stable state theory and regime shifts between these states, as well as a continuation of our education on ecological resilience. Complex systems are dynamic and when presented with a large enough disturbance or erosion of resilience through internal changes to stabilizing feedbacks may rapidly shift into a fundamentally different form of the system. We use the example of lakes, one clear-water lake and one with excess nutrients pollution from runoff causing the lake to become turbid and dominated by toxic cyanobacteria. These lakes are in the same location and exist under the same climatic conditions and yet they are fundamentally different. How? There has been a regime shift as one lake switched from a clear-water state to a turbid, cyanobacteria-dominated state, but how can such similar lakes end up in different states? To answer that question, we will visit the concepts of alternative stable states and regime shifts in depth.
Analysis of Augmented Block Design Using R Part 1: An Introduction to an Augmented Design Approach in Plant Breeding
When planning any science research project to gain information for a particular goal or objective, much thought is placed into what is called the experimental design or layout of the experiment. This is important to ensure the researcher is able to obtain useful data which can later be analyzed and provide information as to whether or not the scientific hypothesis being tested is supported or rejected. In this eLesson series we will look at a plant breeding experiment which uses the Augmented Design and utilize tools in R to analyze the data.
Analysis of Augmented Block Design Using R Part 2: Analyzing Treatments as Fixed Effects
When planning any science research project to gain information for a particular goal or objective, much thought is placed into what is called the experimental design or layout of the experiment. This is important to ensure the researcher is able to obtain useful data which can later be analyzed and provide information as to whether or not the scientific hypothesis being tested is supported or rejected. In this eLesson series, we will look at a plant breeding experiment which uses the Augmented Design and utilize tools in R to analyze the data.
Analysis of Augmented Block Design Using R Part 3: Analyzing Treatments as Random Effects
When planning any science research project to gain information for a particular goal or objective, much thought is placed into what is called the experimental design or layout of the experiment. This is important to ensure the researcher is able to obtain useful data which can later be analyzed and provide information as to whether or not the scientific hypothesis being tested is supported or rejected. In this eLesson series we will look at a plant breeding experiment which uses the Augmented Design and utilize tools in R to analyze the data.
Aparición de resistencia a herbicidas, en una población de malezas
El uso repetido del mismo herbicida, puede provocar poblaciones de malezas que consisten de biotipos susceptibles (S) que son controlados y biotipos resistentes (R), que escapan al control para producir y retornar semilla con la característica de resistencia, al banco de semillas del suelo. Esta lección se enfocará en la dinámica poblacional de una población de malezas mezclada con biotipos S y R. Se comparará y contrastará la tasa a la que aparecen malezas resistentes en una población bajo diversas presiones de selección. ****** Esta lección se enfocará en la dinámica poblacional de una población mezclada (biotipos susceptibles y resistentes a un herbicida), y comparar y contrastar la tasa a la cual aparece resistencia al herbicida, en una población de malezas mezclada, bajo diversas presiones de selección.
Aplicaciones prácticas de la fisiología de los herbicidas en las plantas
Esta lección se focaliza en el impacto de las características de la planta y el herbicida, importantes para determinar el desempeño del herbicida. Se usarán imágenes visuales para ilustrar varios principios, incluyendo el sitio de absorción del herbicida en la planta, transporte, el sitio de acción sensible, y efectos del ambiente sobre el desempeño del herbicida. Esta información provee la base para maximizar la utilidad del uso de los herbicidas.
Appearance of Herbicide Resistance in a Weed Population
Through the repeated use of the same herbicide, weed populations can consist of susceptible (S)-biotypes that are controlled and herbicide resistant (R)-biotypes that are left behind to produce and return seed with the resistance characteristic back into the soil. This lesson will highlight the population dynamics of a mixed weed population, containing S- and R-biotypes, and compare and contrast the rate at which herbicide resistant weeds appear in a population under a diversity of selection pressures. This lesson will highlight the population dynamics of a mixed (herbicide susceptible and resistant biotype) weed population, and compare and contrast the rate of appearance of herbicide resistance in a mixed population under a diversity of selection pressures.
Application of Molecular Marker Technology to QA/QC in Plant Breeding
Quality Assurance and Quality Control (QA QC) are key for developing effective plant breeding programs which make the most impact for the resources available. Molecular markers can greatly enhance Quality Assurance and Quality Control in plant breeding. It is therefore important to know what is meant by QA QC, how markers are used in QA and QC, how to assess the resultant data, and how to make decisions on selecting lines to move forward in the breeding-to-market process. This lesson is written for plant breeders who are interested in or beginning to use molecular marker technology in quality assurance and quality control in plant breeding.
Asteraceae
This lesson contains information about the flower, fruit, foliage, and form of plants in the Asteraceae family. Additional resources on its uses in plant landscapes, how to grow them, and control pests and diseases are included.
Auxin and Auxinic Herbicide Mechanism(s) of Action - Part 1 - Introduction
The selective control of broadleaf weeds in cereal grain crops by auxinic herbicides has made this group one of the most widespread and important herbicide families in use. These herbicides were the first organic herbicides developed that were selective or able to kill one group of plants, but not another (i.e. kill broadleaf, but not grass plants). This lesson will introduce the major features of these herbicides, discuss their major uses and describe the symptoms of the injury they cause as well as introduce how they kill sensitive plants.
Auxin and Auxinic Herbicide Mechanism(s) of Action - Part 2 - Advanced
The selective control of broadleaf weeds in cereal grain crops by auxinic herbicides has made this group one of the most widespread and important herbicide families in use. These herbicides are thought to act as hormone mimics. This lesson will detail how these herbicides are related structurally and physiologically to the natural plant hormone, auxin (indole-3-acetic acid; IAA) and explain the biochemical mechanisms which may be involved in their action.
Backcross Breeding 1 - Basic Gene Inheritance
This lesson reviews the basics of gene inheritance. It compares plants that are homozygous, heterozygous, and hemizygous for an allele and how gene expression is affected by the dominance of an allele. It also explains how to use a Punnett square to predict genotypic and phenotypic ratios of offspring.
Backcross Breeding 2 - The Backcrossing Process
This lesson discusses the final stage of developing genetically engineered crops. The need for backcrossing, and the steps of this breeding method are described. Yield lag, yield drag, and gene stacking are also discussed.
Basic Biotechnology
An introduction to traditional cross-breeding and biotechnology, particularly genetic engineering. Includes the historical uses of biotechnology, the definition of biotechnology, and examples of biotechnology.
Biodegradable Mulch, Analyzing Research Articles and Statistical Data
Learn to read and interpret scientific peer-reviewed articles and how they are structured. Next dive into some biodegradable mulch data where you will visualize and answer questions that will adjust your thinking to think like a scientist. After analyzing data we will next go into the realm of statistical data and learn how to calculate standard deviation and standard error.
Biotechnology and Allergenicity
This lesson discusses some of the issues that consumers experience following exposure to certain foods. This lesson will define and discuss food allergies, properties of food allergens, as well as the allergenicity of foods produced through agricultural biotechnology.
Biotechnology and Nutrient Composition
Biotechnology techniques used to make nutritional changes in plants. Examine how protein, fatty acid, carbohydrate, micronutirents, and phytonutrients contents in food have been altered.
Biotechnology and the Consumer
This lesson discusses the risks and benefits of biotechnology as well as the common consumer concerns with biotechnology.
Biotechnology Practice Applications
Examines functional foods, allergens, genetic engineering, and food safety.
Breeding for Grain Quality Traits: The challenges of measuring phenotypes and identifying genotypes.
An introduction to methods and difficulties of plant breeding. Comparisons are made between corn, proso millet, wheat, and sorghum.
Breeding for Resistance in California Strawberry to Verticillium Dahliae
This e-library lesson will focus on breeding resistant strawberries to the fungus Verticillium dahliae, common name Verticillium wilt. This is a serious fungal disease that can result in a loss of 50% or more of a strawberry harvest when grown in infested soil . This lesson is written for undergraduate and graduate students who are currently studying plant pathology or the management of crop disease. The main goal is to provide an example of how a cultivar can be made more resistant to a plant pathogen with the use of plant breeding methods.
Buffalo Grass Field Data Part 1: Scoring and Data Analysis
An introduction on how to collect and organize data in an experimental setting. This lesson uses Buffalo grass plots to demonstrate how visual qualities can be converted into a numerical values or data. Then learn how to use that data to create graphs and figures to help conceptualize which of the plots would be ideal for a turf grass setting.
Buffalo Grass Field Data Part 2: Editing and Graphing Data
Build on your skills and learning from Buffalo Grass Experiment Lesson part 1, as we continue to gain experimental skills using buffalo grass plots. Learn how to analyze data by deciphering between good and bad data and knowing when to take out outlying data. Also learn how to manage data by creating a mean and a line graph to make data easier to interpret.
Case of the Drought Resistant Genetically Engineered Corn Plant
This scenario accompanies the online lesson, "Transpiration - Water Movement Through Plants", and is designed to allow you to apply the concepts learned in that lesson to a real-life problem.
Cellular Absorption of Herbicides
Before a herbicide can kill a plant, it must be absorbed by the plant’s leaves or roots and enter a cell which possesses the metabolic pathway the herbicide targets. This lesson follows the fate of the herbicide after it has entered the plant via leaf or root tissue, and explains the factors controlling transport of a herbicide into plant cells. This lesson describes 1) the barriers to herbicide entry, such as the plant cell membrane, 2) the role that the herbicide’s chemical properties have on the rate of cellular absorption, and 3) experimental approaches to understanding herbicide absorption at the cellular level.
Chi-Square Test for Goodness of Fit in a Plant Breeding Example
In plant breeding and genetics research, plant breeders establish a hypothesis to explain how they think a particular trait is inherited, such as if it is due to one gene with complete dominance, an interaction of more than one gene, or quantitative inheritance, with many genes contributing, etc. The question then is how do plant breeders determine if the data is close enough to what they expected to determine if the hypothesis is supported or not? Following a tomato disease resistance example in this lesson, you will learn a simple statistical test that breeders can use to conclude if the experimental data supports their hypothesis of single gene, completely dominant inheritance.
Clasificación de los herbicidas
Esta lección se enfoca en entender el sistema de clasificación en el cual están organizados los herbicidas. Terminología como clasificación, jerarquía de clasificación, ejemplos de clasificación y un breve resumen de los ocho modos de acción, se discuten en esta lección. Una vez que esto se entiende, es mucho más fácil comprender herbicidas similares y saber por qué estos pueden exhibir ciertos síntomas en malezas y cultivos.
Corn Breeding: Introduction to Concepts in Quantitative Genetics
This is the second in a series of lessons specifically designed to instruct individuals without any formal training in genetics or statistics about the science of corn breeding. Individuals with formal training in genetics or statistics but without any training in plant breeding also may benefit from taking these lessons.
Corn Breeding: Lessons From the Past
This is the first in a series of lessons specifically designed to instruct individuals without any formal training in genetics or statistics about the science of corn breeding. Individuals with formal training in genetics or statistics but without any training in plant breeding also may benefit from these lessons.
Corn Breeding: Mass Selection
This is the fourth in a series of lessons specifically designed to instruct individuals without any formal training in genetics or statistics about the science of corn breeding. Individuals with formal training in genetics or statistics but without any training in plant breeding also may benefit from taking these lessons.
Corn Breeding: Types of Cultivars
This is the third in a series of lessons specifically designed to instruct individuals without any formal training in genetics or statistics about the science of corn breeding. Individuals with formal training in genetics or statistics but without any training in plant breeding also may benefit from taking these lessons.
Corn Flowers and Hybrid Seeds
An explanation of how hybrid corn is grown, and how the monoecious nature of corn is used to manipulate the cross-breeding.
Corn Rootworm - Part 1: Description of Corn Rootworm and Other Early Season Corn Pests
This lesson will discuss the corn rootworm complex, which consists of the northern, western, and southern corn rootworm, focusing on the northern and western species. The information in this lesson will focus on the biology of corn rootworms in the north central Corn Belt, including Iowa and Nebraska. Crop producers, crop scouts, students, and the general public may find the information in this lesson helpful for identifying corn rootworm, other corn pests, and the feeding damage caused by each insect.
Corn Rootworm - Part 2: Corn Rootworm Management
This lesson will discuss economic thresholds and management options related to the corn rootworm complex consisting of the northern, western, and southern corn rootworm, with emphasis on the northern and western species. The information in this lesson will focus on the north central Corn Belt, including Iowa and Nebraska. Crop producers, crop scouts, students, and the general public may find this lesson helpful for obtaining information about developing a management plan to control corn rootworm.
Corn Rootworm: Small insect, big impact
Corn rootworm can cause devastating effects to corn yields. The focus of this lesson is the ongoing research of scientists as they work to combat the resistance of Corn rootworm to control measures. The importance of this research in developing Insect Resistance Management strategies is discussed.
Correlation Using the R Statistical Package - Part 1: An Introduction to the Canopy Spectral Reflectance (CSR) Experiment
When conducting research, sometimes it is important to know if two different characteristics are related to each other. An example in plant breeding might be if deep roots are somehow related to drought resistance. Correlation is a measure of dependence or statistical relationship between two random variables or two sets of data. Correlation measures the strength of the linear relationship between two variables, such as the deeper roots are, the more the plant can withstand drought. Not all climates will indicate a good correlation between these. "R" is a free to use software programming language and software environment for statistical computing and graphics. R is widely used in both academia and industry for data analysis and modeling. In this lesson module we will introduce you to a real world experiment in which one objective is to determine which Canopy Spectral Reflectance (CSR) indices and growth stages best correlate with yield and/or yield components under water stressed and non-stressed treatments in 300 winter wheat lines. This lesson does not require you to have any prior knowledge of the R language and environment, nor do you need to be fluent in plant breeding research. However users who have basic understanding of a statistical technique called "correlation" will be able to take better advantage of the lesson. If you need a refresher on correlation, watch Statistics 101: Understanding Correlation by Brandon Foltz on YouTube or follow this link: https://www.youtube.com/watch?v=4EXNedimDMs&list=TLaKfQPP3YM9TSdqIXpG_ZbtHWgaOu-Awh
Correlation Using the R Statistical Package - Part 2: Data Preparation
In the first module we looked at the field experiment as described by the domain scientist and we also looked at the data from the perspective of the analyst. In this module we will learn how to install the R software then we will explore a few basics of data files that are generated by sensors and data loggers. We will also take a quick tour of tools that may be used to look at the raw data. We will then develop a methodology that may be taken with respect to preparing raw data for a computation that helps us analyze. Finally, we will look a few "data types" that are typically used in R.
Correlation Using the R Statistical Package - Part 3: R Functions and Scripts
In this lesson module we will calculate the correlation coefficient between one of the Canopy Spectral Reflectance (CSR) indices with yield and/or yield components under water stressed and non-stressed treatments in 300 winter wheat lines. As we analyze one aspect of the recorded data we will demonstrate the concepts of R programming and computational thinking to accomplish this goal.
Cytoplasmic Inheritance
This lesson was designed for individuals who have some knowledge of science but do not have formal training in genetics. However, cytoplasmic inheritance is not as well known as nuclear genetics so this material may be interesting to the professional who wants to know more about this esoteric subject.
Defoliation - Grazing Response
A scenario to accompany 'Perennial Plant Response to Defoliation" and provide an opportunity to apply the concepts learned in that lesson to a real-life problem
Deliberate Mechanical Defoliation of Perennials
A scenario to accompany 'Perennial Plant Response to Defoliation" and provide an opportunity to apply the concepts learned in that lesson to a real-life problem
Descripción de la Ingeniería Genética
La ingeniería genética es un tipo de modificación genética que consiste en la adición dirigida de uno o mas genes ajenos al genoma de un organismo. Un gen posee la información que dará a un organismo una característica específica.
Descubrimiento y selección de herbicidas
Históricamente, los herbicidas se han descubierto por selección al azar de la actividad sobre malezas de interés, con colecciones de químicos. Aunque totalmente empírico, este enfoque ha sido sorprendentemente exitoso y ha producido esencialmente todos los herbicidas comerciales que hoy se usan. Más recientemente, las compañías de agroquímicos han adoptado estrategias direccionadas, usando ensayos in vitro, relaciones estructura del compuesto/actividad, y ensayos de perfilamiento de mARNs, proteínas y metabolitos. Estos últimos enfoques, en combinación con filtros estrictos, están diseñados para explotar avances recientes en la tecnología y para tomar ventaja de nuestro mejor entendimiento de los sistemas biológicos.
DNA and Chromosome Structure
This lesson describes the chemical structure of DNA and how the structure relates to genes and chromosomes. The replication of DNA prior to cell division to create the chromatids of replicated chromosome is illustrated, showing how the main DNA replicating enzymes work together in living cells.
DNA and DNA Extraction
This lesson discusses what DNA is and how it relates to genes and chromosomes. How and why DNA is extracted in the genetic engineering process is also covered.
DNA for Dinner 4-H Curriculum
It is “(DNA for) Dinner” Time! The five lessons in this curriculum, designed for fifth through eighth grade participants in classroom or afterschool venues, include: Dare to Be Different (organisms, genetic diversity); Language of Life (genomes, genetic code); DNA for Dinner (genes, DNA, reproduction); Building Blocks to Organisms (amino acids, proteins, enzymes); and From Bread to Biotech (classical breeding, genetic engineering, restriction enzymes). Each lesson has an introduction, open-ended discussion questions, math puzzles and three to five activities to demonstrate key points of the lesson. Some activities are computer-based, some hands-on and some are physical activities. Each lesson targets National Science Education Content Standards in Life Sciences for Grades 5 through 8. The curriculum development was funded by the American Society of Plant Biologists and completed in November 2010.
Ecological Resilience
This entry is an introduction to the concept of ecological resilience. Resilience is the amount of disturbance a system can withstand without transitioning to an alternative state characterized by fundamentally different structure and function. Disturbances include fire, flooding, grazing, and all kinds of modern human influences like pollution, and overharvesting of resources. Concepts of ecological resilience apply to complex systems such as the human body, ecosystems, societies, and economies. Overall, the concepts of ecological resilience can help us to better understand, conserve, and remediate Earth’s ecosystems in the face of historically unprecedented anthropogenic change while also understanding the dynamic processes at work within social systems of our own creation.
Electrophoresis: How scientists observe fragments of DNA
Describes gel electrophoresis and how the method is used in molecular genetic analysis.
Embryogenesis
Embryogenesis is the process of initiation and development of an embryo from a zygote (zygotic embryogenesis) or a somatic cell (somatic embryogenesis). This lesson discusses the steps in plant growth at the cellular level from the very beginning through maturity.
Erosion
Soil erosion is a global problem. Each year, erosion costs billions of dollars in loss of land productivity, damage from soil sediment deposition and subsequent restoration costs, and harm to plant, animal, and human health due to air and water pollution. This lesson will consider the impacts of erosion at local, regional, national, and international levels. It will discuss how erosion occurs and the main factors that contribute to erosion. In addition, the different types of water and wind erosion will be discussed. The lesson is written to target educational needs of lower level undergraduate students and is open for use by the public and educational institutions. Depending on the goals/objectives of a course, training, workshop, part or all sections of the lesson could be used.
Erosion Control Measures
This lesson will discuss erosion control practices in the agricultural and construction environments. The impact of erosion management practices will be demonstrated with exercises using a USLE calculator.
European Corn Borer and Bacillus thuringiensis
This lesson contains information about the history, life cycle, and host plants of the European corn borer and information relating to the history and biology of Bacillus thuringiensis.
Evolution
This lesson describes an evolution story that is unfolding today in farmers fields around the world.
Flowering Principles
What is a "flower" and what are its structures? How do the male and female parts operate to produce seed? Monoecious versus dioecious; perfect versus imperfect.
Foliar Absorption and Phloem Translocation
Herbicides must be absorbed into plants in order to be effective. Herbicide absorption can occur through leaves, roots or both. The process by which herbicides kill weeds, called mode of action, requires herbicide absorption and may also require herbicide movement or translocation within the plant. Translocation means that the herbicide moves from the site of absorption to some other plant part. Foliar applied herbicides that have the necessary characteristics to move in the phloem will translocate to areas of the plant that are actively growing; however, not all foliar-applied herbicides move from the leaves that intercepted the spray solution. Herbicides that are absorbed but not translocated are called contact herbicides, while herbicides that translocate to shoot or root meristems are called systemic herbicides. Absorption and translocation of xylem mobile herbicides will be discussed in another lesson.
From Seed to Seed: A Pictorial Story Showing How a Bean Plant Grows: Part 1 The Developing Bean Plant
Ever wonder how plants produce your food? Well, these picture books show you how a red kidney bean plant germinates and grows (Part 1), flowers, and fruits (Part 2). Along the way in our pictorial journey, we take the developing seed and the plant apart so you can see the tissues and cells that comprise the bean and the plant. In Part 3 we provide instructions so that you can do it too!!
From Seed to Seed: A Pictorial Story Showing How a Bean Plant Grows. Part 2 The Flowering and Mature Bean Plant
If you thought watching the bean plant as it germinated and grew was cool, you’ll love this section! In Part 2 not only will you see the bean plant flower, you will also see the cells that make up the roots, stem, and leaves. All by virtue of microscopy.
From Seed to Seed: A Pictorial Story Showing How a Bean Plant Grows: Part 3 How to Grow and Observe Red Kidney Bean Plants
Yes, anyone can grow beans! In Part 3, you will find all the information you need (and more) to grow and observe red kidney bean plants. Welcome to plant land!
Gene Cloning
This lesson covers the utilization of gene cloning to isolate and copy a specific gene of interest. The transformation of bacteria with plasmids containing antibiotic resistance genes to make gene libraries and the selection of bacteria colonies that contain the specific gene of interest are described.
Gene Cloning Part 1: The Mechanics of Recombinant DNA
This lesson describes how DNA molecules can be recombined to make recombinant DNA and how special DNA molecules called plasmids allow scientists to clone genes.
Gene Cloning Part 2: Making and Screening Gene Libraries
This lesson teaches how a specific gene can be identified from among the thousands of genes that can be cloned from an organism.
Gene Design 1 - Gene Regions
This lesson describes the three gene regions and their roles in gene expression. It also discusses how the regions of a gene can be altered to obtain desired trait expression.
Gene Design 2 - Gene Constructs
This lesson builds upon the gene region lesson discussing the gene construct of currently used hybrids and explaining how these combinations result in a particular gene expression.
Gene Expression Part 1: Reading Genes to Make Proteins
This lesson describes the steps involved in a cell as DNA sequence information is read to make RNA and RNA is read to make proteins.
Gene Expression Part 2: Expression of Herbicide Resistant ALS Genes in Plants
This lesson describes how changes in the DNA sequence of a gene can alter the synthesis of a protein and thus influence traits such as herbicide resistance.
Greening Up the Greens - Transpiration Application Scenario
A scenario to accompany the online lesson, 'Transpiration - Water Movement Through Plants'.
Herbicidas que Actúan A través de la Fotosíntesis
En esta lección se examinarán los herbicidas que afectan los procesos celulares relacionados con la utilización de la luz, causando así daños a las plantas. Existen cuatro mecanismos básicos que serán estudiados: herbicidas que obstruyen la síntesis de protoporfirina IX; herbicidas que inhiben la síntesis de carotenoides; herbicidas que obstruyen la transferencia de electrones en el fotosistema II; y herbicidas que substraen electrones del fotosistema I. Todos ellos comparten la misma habilidad de causar daños celulares en presencia de luz.
Herbicide Classification
This lesson focuses on understanding the classification system into which herbicides are organized. Terms of classification, classification hierarchy, examples of classification and a brief overview of the eight modes of action are all discussed in this lesson. Once this is understood it is much easier to grasp similar herbicides and know why they may exhibit certain symptoms to weeds and plants alike. Objectives: 1. Understand how herbicides are classified and why it is important for managing herbicide resistance 2. Understand the Importance of classification and herbicides by mode of action rather than chemical family 3. Be able to tell the difference between mode of action and site of action 4. Be able to differentiate between herbicide families, modes of action, and sites of action 5. Understand common name, trade names and sites of absorption
Herbicide Discovery and Screening
Historically, herbicides have been discovered by randomly screening collections of chemicals for activity on target weeds. While totally empirical, this approach has been surprisingly successful and has produced essentially all commercial herbicides currently in use. More recently, agrichemical companies have adopted directed strategies using in vitro assays, compound structure/activity relationships, and profiling assays of mRNAs, proteins, and metabolites. These latter approaches, in combination with high-throughput screens, are designed to exploit recent advances in technology and take advantage of our increased understanding of biological systems.
Herbicide Resistance: Mechanisms, Inheritance, and Molecular Genetics
Explanation of the biochemical mechanisms and genetics of herbicide-resistance in weeds and the management and spread of herbicide-resistant weeds in relationship to the biochemical mechanisms and inheritance of resistance.
Herbicides That Act Through Photosynthesis
This lesson will examine herbicides that adversely affect light-related processes, thereby causing damage to plants. There are four basic mechanisms that will be studied in this class of agents: herbicides that inhibit or block synthesis of Protoporphyrin IX; herbicides that inhibit synthesis of carotenoids; herbicides that block Photosystem II electron transfer; and herbicides that divert electrons from Photosystem I. All share the ability to cause cellular damage in the presence of light.
Heterogeneity
This entry discusses heterogeneity in the context of ecological landscapes and how the heterogeneity impacts the resilience of the system. Heterogeneity is closely linked to the scale of measurement, both spatially and temporally. We will walk through a simple example that highlights how the scale of observation can impact the heterogeneity of the system. The differences between functional and measured heterogeneity will also be explained. Finally, heterogeneity will be discussed in the context of its utility to management and how it can be used to understand the resilience of agro-ecosystems.
High Throughput Phenotyping in Plant Breeding
An introduction to plant breeding and high throughput phenotyping. This lesson outlines the steps and goals of the plant breeding process and identifies areas that can be improved with high throughput phenotyping methods. It also covers the steps necessary to collect and process UAV-based high throughput phenotyping data to make reliable plant breeding decisions.
Inhibidores de la Síntesis de Aminoácidos Aromáticos
En esta lección se detallarán los procesos bioquímicos que son afectados por los herbicidas que inhiben la síntesis de aminoácidos en las plantas. Se describirá también la importancia de los aminoácidos y las proteínas. De igual manera, se presentará un estudio detallado del herbicida glifosato [N-(fosfonometil)-glicina], incluyendo los avances hechos por la biotecnología.
Inhibitors of Aromatic Amino Acid Biosynthesis
This lesson will detail the biochemical mechanisms that are affected by herbicides which inhibit a plant’s ability to synthesize amino acids. The significance of amino acids and proteins will also be described. The herbicide glyphosate, will be studied at length, including the advances made by biotechnology.
Inhibitors of Branched Chain Amino Acid Biosynthesis
Herbicides that inhibit the production of the branched chain amino acids valine, leucine and isoleucine are used for total vegetation management and selective weed control in a wide variety of crops. There are currently four different chemical families that share this MOA. Before the development of glyphosate-tolerance crop technology, branched chain amino acid inhibitors were the mainstay for several major row crops. While this is still a very important herbicide MOA, the major increase in herbicide resistance weeds since 1980 has been the direct result selection pressure from these herbicides. There are currently more weed species resistant to branched chain amino acid inhibitors than any other herbicide MOA.
Inhibitors of Fatty Acid Synthesis and Elongation
Fatty acid synthesis and fatty acid elongation are two parts of a critically important pathway in plants. The endproducts are essential components of cell membranes, waxes, and suberin. Two chemical families of herbicide (groups that share similar chemical structures) inhibit fatty acid synthesis, while fatty acid elongation is inhibited by two other families. This lesson will provide an overview of fatty acid synthesis and elongation, and explain where herbicides inhibit the pathway. Mechanisms of resistance to these herbicides will be described.
International Plant Protection Convention (IPPC)
Overview of the International Plant Protection Convention (IPPC). The eLesson will explain the key elements of the IPPC and the importance of preventing pest spread and establishment as a result of the international trade of plants and plant products.
International Treaty on Plant Genetic Resources for Food and Agriculture
Overview of the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA). The eLesson will explain the key elements of the ITPGRFA and the importance of having access to genetic resources to support breeding improved plant varieties.
International Union for the Protection of New Varieties of Plants (UPOV)
Overview of the International Union for the Protection of New Varieties of Plants (UPOV). The eLesson will explain the key elements of the 1991 UPOV Convention and the importance of intellectual property protection to encourage investment and innovation in plant breeding.
Introduction to Biofuel: Perennial Grasses as a Feedstock
This lesson covers what biofuels are (including 1st, 2nd, and 3rd generation biofuels) and explains why they are important.
Irrigation Home Study Course
A self-paced course in agricultural irrigation. The intent of this Home Study Course is to increase the user’s awareness and understanding of irrigation management concepts. This in turn can help producers reduce irrigation application amounts and increase uniformity of application, thereby reducing deep percolation and runoff. The end result can be reduced irrigation costs, increased efficiency, increased yields and reduced surface and groundwater contamination. The target audience for this course includes: crop consultants, agency personnel, irrigated crop producers and others interested in improving their irrigation water management skills. There is additional information on irrigation management on the UNL Water webpage: http://water.unl.edu/web/cropswater/home We recommend that you print a few of the addenda, especially the Tables and the Equations. For best printing results, set the printing properties to Portrait and, if available, to print both sides. Upon completing a chapter you can take the quiz by clicking on the "Quiz" link included in each lesson; you may use your printed addenda while taking each quiz. To earn CEU credit, you'll need to get 8 of 10 questions correct. You may retake quizzes as many times as you wish. Chuck Burr Extension Educator, Univ of Nebraska chuck.burr@unl.edu
Just the facts
Description of the fundamental concepts of trait inheritance in sexually reproducing species.
La Interacción de la Luz con las Biomoléculas
En esta lección se describe la naturaleza de la luz, la energía de los fotones y como dicha energía puede ser transferida a las biomoléculas. Se describen también tanto los procesos benéficos como los procesos dañinos por medio de los cuales las biomoléculas disipan la energía recibida.
La Transpiración - Movimiento del Agua a Través de las Plantas
La transpiración es la pérdida de agua en forma de vapor por las plantas. El agua es absorbida del suelo por las raíces y transportada en forma líquida por el xilema hacia las hojas. En las hojas, unos pequeños poros permiten que el agua (H2O) escape a la atmósfera en forma de vapor, al tiempo que se permite la entrada de bióxido de carbono (CO2) para la fotosíntesis. De toda el agua absorbida por las plantas, menos del 5% es retenida y utilizada para crecimiento y almacenamiento. En esta lección se explicará porque las plantas pierden tanta agua, la ruta que ésta sigue dentro de la planta, como pudieran las plantas controlar la pérdida excesiva de agua y como las condiciones ambientales influyen en la pérdida de agua por las plantas.
Linkage - Part 1 - Biology and Mathematics of Linked Genes
You’ll learn to calculate basic map distances from dihybrid (two trait) data and combine map distances from multiple dihybrid crosses to make a linkage map.
Linkage - Part 2
Learn to make predictions about inheritance using map unit distances and genetic markers, assemble maps from multiple-point linkage data, define the relationship between linkage maps, linkage groups and genome maps, and describe how DNA or molecular markers are observed and used in gene mapping.
Los Pigmentos Vegetales y la Fotosíntesis
En esta lección se examinarán las dos principales clases de pigmentos fotosintéticos: las clorofilas y los carotenoides. Se analizarán sus estructuras bioquímicas y su biosíntesis, y se explicará además la organización de estos pigmentos en los sistemas fotosintéticos, que son complejos proteicos que colectan y convierten la energía luminosa en energía química.
Manure Phosphorus and Surface Water Protection I: Basic Concepts of Soil and Water P
This lesson focuses on the process of eutrophication; the relationship between land application of manure and soil phosphorus (P) dynamics on P delivery to surface waters; and on the P dynamics in water bodies that result in increased P available to aquatic vegetation.
Manure Phosphorus and Surface Water Protection II: Field and Management Factors
This lesson describes how source factors, including soil characteristics and management practices, affect phosphorus (P) delivery to surface waters; and also discusses how crop producers can control these factors through their management practices.
Manure Phosphorus and Surface Water Protection III: Transport Factors
This lesson addresses transport factors that may contribute to phosphorus (P) delivery to surface waters. Erosion, runoff, subsurface flow, drainage, and distance to surface water are the main factors. In some places, wind erosion may also be important. The effects of management practices on P transport are discussed, and water-related P transport processes are described in detail.
Manure Phosphorus and Surface Water Protection IV: Assessment of the Risk of Agricultural P Delivery
Addresses the assessment of potential for P delivery to surface waters resulting from the interaction of the source and transport factors addressed in Lessons II and III. The basic concepts and applications of P indexes as risk assessment tools are explored.
Marker-Assisted Selection
A method of selecting desirable individuals in a breeding scheme based on DNA molecular marker patterns instead of, or in addition to, their trait values. A tool that can help plant breeders select more efficiently for desirable crop traits.
MB1 - Molecular Breeding: the use of molecular markers for efficient crop improvement
Classical plant breeding is the intentional interbreeding and selection of plant varieties with the goal of producing new varieties with improved properties (e.g. higher yield, bigger fruit, disease resistance, etc.). Marker-Assisted Breeding (MAB) combines classical plant breeding with the tools and discoveries of molecular biology and genetics, most specifically the use of molecular markers.
MB2 - Selection of Markers for Molecular Breeding
Molecular Markers (variants of DNA sequences) are identifiers (or ‘tags’) of certain aspects of a phenotype and /or genotype which could be exploited by plant breeders for incorporating desirable traits into their advancing germplasm. It is important therefore that we understand the proper usage of markers, be able to select the proper marker types, have an understanding of DNA extraction protocols and the general organization of the crop genome of interest. This lesson is written for plant breeders who are interested in or beginning to use molecular markers.
MB3 Genetic Diversity & Germplasm Selection
A main goal of plant breeders is to develop lines improved for particular traits, for example larger fruits, quick maturing, etc. Genetic diversity is the basis for all crop improvement; therefore it is crucial to be able to assess and understand the diversity available for a crop before developing a breeding strategy. Using molecular analysis techniques it has been demonstrated that not all genotypes are reflected in a phenotype (important alleles may be masked by other alleles) and therefore molecular level analysis is a better tool to assess and measure genetic diversity. The diversity available in genebanks as well as wild relatives can be an important resource in increasing crop diversity. This eLesson contains three parts: genetic diversity, selecting for desired characteristics and effects on biodiversity, and preserving and improving genetic diversity.
MB4 Phenotyping in MAB
Aspects related to Marker-Assisted Breeding
Mecanismo(s) de Acción de las Auxinas y los Herbicidas Auxínicos - Parte 1- Introducción
Descripción: El control selectivo de malezas de hoja ancha en cultivos de cereales utilizando herbicidas auxínicos ha hecho de éstos una de las familias de herbicidas actualmente en uso más ampliamente distribuidas e importantes. Estos herbicidas fueron los primeros herbicidas orgánicos desarrollados que presentaron selectividad; es decir, capaces de matar un cierto grupo de plantas sin afectar a otros grupos (por ejemplo: matar plantas de hoja ancha pero no las de hoja angosta; en este documento se utilizará el término "gramíneas" para referirse a las plantas de hoja angosta o cereales). En esta lección se presentarán las principales características de los herbicidas auxínicos, se discutirán sus principales usos y se describirán los síntomas de daño que causan. De igual forma, se indicará la forma en que estos herbicidas matan a las plantas sensibles.
Mecanismo(s) de Acción de los Herbicidas Auxínicos - Parte 2 - Nivel Avanzado
Descripción: El control selectivo de malezas de hoja ancha en cultivos de cereales por los herbicidas auxínicos ha hecho de éstos una de las familias de herbicidas actualmente en uso mas ampliamente distribuidas e importantes. Se cree que estos herbicidas actúan como simuladores hormonales. En esta lección se detallará la relación estructural y fisiológica entre los herbicidas auxínicos y la fitohormona natural auxina (ácido indol-3-acético; IAA por sus siglas en inglés) y se explicarán los mecanismos bioquímicos que pueden estar involucrados en su modo de acción. Se revisará el mecanismo de transporte de célula a célula y la absorción de las auxinas por las células, así como también la forma en que estas moléculas causan elongación celular e inducen la síntesis de etileno. De igual forma, se describirán los receptores, las rutas de transferencia de señales y los cambios en expresión genética inducidos por la fitohormona natural IAA y su relación con la actividad de los herbicidas auxínicos.
Metabolism of Herbicides or Xenobiotics in Plants
This lesson will take an in depth view of how plants handle foreign chemicals (xenobiotics) such as herbicides. It will discuss the three main phases that plants use to handle toxic chemicals, which enzymes are involved in these biochemical conversions, how these processes help protect crops again phytotoxic chemicals and consider the importance of these processes to successful weed management.
Mitosis and Meiosis and the Cell Cycle
Multicellular organisms such as plants and animals are composed of millions to trillions of cells that work together. This lesson details the steps of somatic cell division to produce identical cells by mitosis and germline cell division to produce gametes by meiosis. Emphasis is on what is happening genetically as these new cells are made in multicellular, sexually reproducing organisms.
Native Plant Breeding: Bringing the Beauty of Nature Home
Looks at how native plant breeders create plants with new combinations of desired traits; the relationship between plants, flowers and seeds; male and female structures flowers; flower types based on structures observed in the flower; and how flower structures impact plant crossbreeding.
Overview of Plant Genetic Engineering
A general description of the overall process of genetic engineering. A basic explanation of the five steps for genetically engineering a crop is provided.
Panarchy
This module discusses panarchy theory, a framework for understanding how systems function and interact across scales. The key idea in panarchy theory is that adaptive cycles are nested together and interact with each other to form what are termed “panarchies.” Within a panarchy, broad scale adaptive cycles influence smaller scale cycles, and smaller scale cycles can influence broad scale ones. This is true of both social and ecological systems. Panarchy theory has been applied to examine regime shifts in ecology as well as company size distribution in economics.
Perennial Grass Growth and Development
Central to the management of perennial grasses in traditional range and pasture and advanced biomass energy production systems is having a firm understanding of how grasses grow and develop. In this lesson module, you will learn about physiology, growth, and development of perennial grasses through animation, text, and video. It will discuss grass seed structures and functions; the process of grass seedling establishment; morphological structures of grasses once they are established; and how perennial grasses grow. This module is written for beginning agronomy, plant science, and natural resource ecology and management students and will be useful for advanced high school students or introductory-level undergraduates. Extension audiences wishing to learn more about perennial grasses will also find the lesson helpful.
Perennial Plant Response to Defoliation - An Overview
Compares the growth of defoliated and non-defoliated perennial plants, with an emphasis on the link between plant structure, growth, and response to defoliation.
Pesticide Resistance Management
Insect pests in agronomic and horticultural systems require careful consideration of resistance management to prevent them from having decreased sensitivity or complete resistance to chemical pesticides. In this lesson, you'll have access to two videos that detail the many considerations of managing pesticide resistance in insects.
Plant Pigments and Photosynthesis
This lesson will examine the two major classes of phototsynthetic pigments, chlorophylls and carotenoids, their biochemical structures and their biosynthesis. The organization of these pigments into photosynthetic pigment, which are protein complexes that harvest light and convert its energy into biochemical energy will be explained.
Polymerase Chain Reaction (PCR)
The polymerase chain reaction (PCR) laboratory technique is used in a variety of applications to make copies of a specific DNA sequence. This lesson describes how a PCR reaction works, what it accomplishes and its basic requirements for success. Examples of interpreting results are given for a seed storage protein (kafirins in sorghum). PCR's strengths, weaknesses and applications to plant biotechnology are explained.
Practical Applications of Herbicide Physiology
This lesson will focus on the impact of herbicide and plant characteristics important in determining herbicide performance. Visual images will be used to illustrate several principles including herbicide site of uptake, translocation, site of action sensitivity, and environmental effects on herbicide performance. This information provides a basis for maximizing herbicide performance.
Producing Grain for Animal, Food, and Industrial Uses
Links to three animations on the topic.
Propagation and Procreation - More of a Good Thing
-Creating unique individuals or perfect little clones -Genetics of it all -Peas in Darwin's pods
Protein Detection in Plants
This lesson will focus on molecular principles involved in the detection of biotechnology derived proteins in crops, using the lateral flow ELISA.
Quantitative Trait Locus (QTL) Analysis 1
This is the first of a two-part series that describes the methods and uses of QTL analysis.
Quantitative Trait Locus (QTL) Analysis 2
This is the second of a two-part series that describes the methods and uses of QTL analysis.
Quantitative Traits
Examines quantitative versus qualitative traits, looking at the use of phenotypes in determining quantitative control of heritability.
Real Time PCR - Some Basic Principles
Real time PCR is a laboratory technique that can perform relatively accurate, reliable and reproducible measurements, to quantitatively determine the presence of specific gene sequences. Its value is being recognized in a variety of applications, including transgenic (GMO) detection. It is becoming increasingly important to know what percentage of a particular transgene is present in an export shipment, for example. Real time PCR can also be used to support more traditional plant breeding techniques, making the process of distinguishing allelic variations more efficient. This lesson explains the principles of real time PCR and its' application, with examples in plant breeding and GMO detection.
Root Absorption and Xylem Translocation
Herbicides must be absorbed into plants in order to be effective. Plant roots and below ground shoots have few barriers to herbicide absorption; however, interactions with soil particles and soil organic matter have significant impacts on the amount of herbicide available for plant absorption. Plant roots and below ground shoots (hypocotyls or coleoptiles) are lipophilic by nature and do not have thick, waxy cuticles like leaves. Lipophilic and hydrophilic herbicides reach the root surface by bulk transport in soil water; however, there are a few examples of herbicides that reach the root as a vapor or gas. Soil-applied herbicides can translocate to the shoot or remain in the root system. Soil-applied herbicides translocate to the shoot in the xylem and tend to accumulate in mature leaves that transpire the most water. The lipophilic/hydrophilic nature of the herbicide will determine if the herbicide translocates to the shoot. Absorption and translocation of phloem-mobile herbicides will be discussed in another lesson.
Scale
Scale represents the physical dimensions of time and space and provides the necessary context for our observations of the world. Different disciplines associate with different scales and confronting the most pressing global issues will require integration of knowledge gained from multiple scales. In this lesson plan we discuss what scale is and how it helps us understand the natural world.
Seed Lab Testing
An overview of seed testing methods in the lab.
Segregation of Genes: The Plant Breeder's Method of Predicting the Future
How plant breeders create families with new combinations of traits and make predictions about the inheritance of traits. Discusses Mendel and Punnett.
Soil Genesis and Development, Lesson 1 - Rocks, Minerals, and Soils
This lesson identifies some common rocks and minerals and how they influence soil formation.
Soil Genesis and Development, Lesson 2 - Processes of Weathering
This lesson identifies the factors of weathering processes and how they influence soil formation.
Soil Genesis and Development, Lesson 3 - Soil Forming Factors
This lesson identifies the five major soil forming factors and discusses how they influence soil development.
Soil Genesis and Development, Lesson 4 - Soil Profile Development
This lesson discusses the processes controlling soil formation and how these processes relate to the characteristics of a soil profile.
Soil Genesis and Development, Lesson 5 - Soil Classification and Geography
This lesson discusses the characteristics of the 12 soil orders defined by the USDA soil classification system, the major factors involved with their formation, and their geographic distribution across the USA and the world.
Soil Genesis and Development, Lesson 6 - Global Soil Resources and Distribution
This lesson discusses soil resources and functions at the global scale.
Soil Genesis and Development, Scenario 1 - Agroecosystem Soil, Food and Fiber
This case study addresses how soil formed in different geographical locations of the world influences food and fiber production.
Soil Genesis and Development, Scenario 2 - Biosolid Addition and Soil Formation
This case study addresses where geographically soil addition of municipal organic wastes occurs and how this addition affects soil profile development and the use of soils as a sustainable resource.
Soil Genesis and Development, Scenario 3 - Soils and Salts
This case study addresses how soil formed in different parts of the landscape influences productivity in the broad sense, of both economic and non-economic flora and fauna.
Soils - Part 10: The Scientific Basis for Making Fertilizer Recommendations
The Scientific Basis for Making Fertilizer Recommendations: In this lesson, you will gain an understanding of the history of fertilizer use and the ideas behind fertilizer recommendations. Three major crop nutrition concepts will be discussed in terms of their benefits and disadvantages. [This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
Soils - Part 1: The Origin and Development of Soil (How Soil Gets a Life and a Name)
In this lesson, you will gain an understanding of the five soil forming factors and will be able to describe how each influences soil development. You will learn to identify common parent materials, determine the age of a soil, identify the types of native vegetation associated with different soils in Nebraska and define soil horizons. [This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
Soils - Part 2: Physical Properties of Soil and Soil Water
This lesson will help you understand the major components of the physical properties of soil. You will learn such terms as texture, aggregation, soil structure, bulk density, and porosity as it relates to soils. You will learn how soil holds and transmits water and cultural practices that enhance or degrade physical properties of the soil. [This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
Soils - Part 3: Soil Organic Matter
In this lesson, you will learn such terms as organic, soil organic matter, nutrient, decomposition, humus, compost, and soil structure. In addition, you will be able to predict the effect of land uses on soil organic matter including the effects of different types of vegetation. [This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
Soils - Part 4: Soil pH
Soil pH is defined and its implications for crop production are described in this lesson. How are soil pH and buffer pH determined? How are these assessments used in lime recommendations? The factors that influence pH variations in soils, the chemistry involved in changing the pH of a soil, and the benefits associated with liming acid soils will be discussed. [This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
Soils - Part 5: Nitrogen as a Nutrient
In this lesson, you will be able to describe the forms of nitrogen found in the soil. The nitrogen cycle and how nitrogen is lost in the environment will be thoroughly discussed. Forms of nitrogen utilized by the plant and the concept of nitrogen credits for such factors as legumes, manure, residual soil nitrogen, and irrigation water will be introduced. [This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
Soils - Part 6: Phosphorus and Potassium in the Soil
This lesson explains the importance of phosphorus fixation and describes methods for applying phosphorus and the advantages (and disadvantages) of each. It also describes the three forms of potassium and how form determines availability of potassium to plants. [This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
Soils - Part 7: Soil and Plant Considerations for Calcium, Magnesium, Sulfur, Zinc, and other Micronutrients
The 16 essential elements for plant growth and the relative quantities of each needed by plants to grow normally will be discussed in this lesson. You will learn to identify the source of specific nutrients in the soil and how to identify specific fertilizer compounds needed in Nebraska. [This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
Soils - Part 8: Characteristics of Fertilizer Materials
The various characteristics of fertilizer materials being sold on the market today will be discussed. You will learn to identify some of the consequences of using each type of fertilizer material and how that material was developed and manufactured. [This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
Soils - Part 9: Fundamentals of Soil Testing
The major emphasis in this lesson is soil testing and understanding the procedures needed to take a representative soil sample. You will understand the term variability, how it affects soil tests, and how a soil test is developed. [This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.]
The Dihybrid Cross and Independent Assortment
Examines the principle of segregation versus the principle of independent assortment and their effects on genetic data; and the concept of dominance.
The Inheritance of Variation
An introduction to genetic inheritance, including the principles of segregation and dominance.
The Interaction of Light with Biological Molecules
This lesson describes the nature of light, the energy within photons and how this energy may be transferred to biological molecules. In addition, the beneficial and harmful methods for de-exciting molecules will be described.
The Kochia and Dicamba Story
This lesson examines the development of herbicide resistant weeds and research conducted to help predict and prevent this resistance.
The New Bts
Bt corn is a general term used to describe corn hybrid farmers buy that have an additional gene added to one on their chromosomes which originated from the soil bacteria Bacillus thuringiensis (Bt). This lesson tells the story of how different hybrids can contain different Bt genes which encode proteins that have toxicity to different corn pest insects.
The Role of JAR1 in Insect Feeding Response
Reveals both the process and the power of conducting experiments with jar1, an Arabidopsis mutant that is insensitive to the hormone jasmonic acid (JA). The organisms of focus for these experiments are Arabidopsis thaliana and Trichoplusia ni.
Theories Behind Plant Tissue Culture
When introducing a foreign gene into a target genome in plant tissue, you need to grow the transgenic cell to a complete plant. This is done by plant tissue culture, a biotechnique based on the concept that an organ, tissue or cell of a plant can be manipulated to grow back into a complete plant.
Transformation 1 - Plant Tissue Culture
This lesson explains the technique of tissue culture as used in plant transformation. It discusses important issues, such as the use of selectable markers, genotype specificity, and tissue culture alternatives.
Transformation 2 - Transformation Methods
This lesson explains the procedure of introducing a new gene into a plant cell (transformation). It discusses the main goals of the transformation process and describes the four main methods of transformation.
Transformation 3 - Transformation Events
This lesson defines an 'event'. It explains the determining factors specific to an event, the qualities of a desirable event, and the identification and selection of desirable events.
Transpiration - Water Movement through Plants
This lesson and its animation follows the journey of water through a plant from its uptake by roots to its evaporation from the leaf surface. How this journey is altered by plant characteristics such as stomata and cuticles as well as by changes in the environment will be described.
Utilization of Grain by Swine and Poultry
Anyone involved in the grain industry needs a thorough understanding of swine and poultry nutrition to ensure grains closely match the dietary needs of these animals.