Heredity and Reproduction - Crop and Soil Science - Lecture Slides, Slides of Botany and Agronomy

Download Heredity and Reproduction - Crop and Soil Science - Lecture Slides and more Slides Botany and Agronomy in PDF only on Docsity! Heredity and Reproduction 1 Docsity.com Heredity and Reproduction • A plant or animal is only as developed as its genetic components. • An animal or plant receives its characteristics from its parents. • Scientists are continously searching for improved crop and animal varieties through Selective Breeding. 2 Read pages 43-45 Docsity.com Heredity and Reproduction page 45 • Controllable traits include: Palatability Heat and drought tolerance Shape and color Oil Starch, sugar, protein Fiber content, height, salt tolerance, flavor Texture, and time to maturity 5 Docsity.com Chapter 3 Objectives page 45 1. How is inheritance of traits in plants regulated? 2. How do dominant and recessive genes affect plant characteristics? 3. How does pollination in plants occur? 4. Why are some plants unable to self pollinate? 5. How do scientists use principles of plant genetics to guide their plant breeding programs? 6. How is biotechnolgy being used to supplement traditional plant breeding programs? 6 Docsity.com Answer these questions 1. What is selective breeding? 2. Identify five controllable traits that scientists can control. 3. Which types of combinations are used in plant breeding. 4. What percent does hybridization increase yield by. 5. When and what was the first major breakthrough in plant breeding? 7 Docsity.com Flowering and Pollination • A flower is complete if it has all four of the the following structures: Sepals, Petals, Stamens, and a Carpel (pistil) 10 Docsity.com Flowering and Pollination • An incomplete flower lacks one or more of the before mentioned structures. 11 Docsity.com Flowering and Pollination • A flower that has both stamens (male reproductive tissues) and a carpel (female reproductive tissues) is a perfect flower. • Imperfect flowers have either stamens or a carpel, but not both. 12 Docsity.com Flowering and Pollination • An incomplete flower is one which has no sepals or petals. • Most cereal and grass plants have incomplete flowers, which makes the flowers less visible. 15 Docsity.com Flowering and Pollination • Flowering is initiated by: • Length of uninterrupted darkness (photoperiodism) • Exposure to low temperatures (vernalization) • Morphological maturity (able to produce seed) 16 Docsity.com Flowering and Pollination • The majority of food-producing plants induce flowering without external stimulation. • As long as they are actively growing, they initiate flowers at almost any temperature or day length. 17 Docsity.com Flowering and Pollination • The Carpel, includes the Stigma, Style, and Ovary. • The Stigma is the swollen end of the Style, is colorful and allows for the pollen to stick. • Pollen grain must land on the Stigma in order for pollination to occur. 20 Docsity.com Answer these questions • 1. What does the Carpel include? • 2. Where does the development of the pollen grain occur. • 3. What is the photoperiodism? • 4. What is meant by morphological maturity? • 5. A flower which has no sepals or petals is which type of flower. 21 Docsity.com Flowering and Pollination • Self-pollination occurs when the anther and the stigma are from the same flower. • From different flowers on the same plant. • From different plants of the same cultivar or variety. • Cross-pollination involves different flowers on plants or different cultivars. 22 Docsity.com Flowering and Pollination • Each pollen grain contains a tube cell and a generative cell. • When the pollen lands on the stigma, germination occurs. 25 Docsity.com Flowering and Pollination • The pollen tube enters the nucleus of the ovule by passing through the Micropyle 26 •The tube cell forms a pollen tube that grows through the stigma and style. Docsity.com Flowering and Pollination • The generative cell has produced two male gametes through the process of Mitosis. 27 Docsity.com Answer These Questions • 1. What is the time between pollination and fertilization. • 2. How many male gametes are produced through mitosis? • 3. What is the function of the gametes? • 4. Pollen enters the nucleus by passing through what opening? • 5. What causes sterility. 30 Docsity.com Genetics and Heredity page 54 • The nucleus of a living cell contains Chromosomes. • Chromosomes contain information about the genetic makeup of the plant. • They transmit the information to offspring. 31 Docsity.com Genetics and Heredity page 54 • Each plant species has the same number of chromosomes in all vegetative cells. • Sex cells have half the number of chromosomes as vegetative cells. 32 Docsity.com Answer these questions 1. Why do vegetative and reproductive cells have varying numbers of chromosomes? 2. Which type of material do chromosomes contain? 3. What does DNA stand for? 4. What does RNA stand for? 5. What is a gene? 35 Docsity.com Genetics and Heredity page 55 • Chromosomes are usually found in pairs in each vegetative cell. • These are called Homologous Chromosomes. • They have the same genes affecting the same traits and are located at the same position along the chromosomes. 36 Docsity.com Genetics and Heredity page 55 • Matching genes on Homologous Chromosomes are called Alleles. • Gene alleles always occur on the same Locus (location) along the pair of chromosomes. • Allelic genes can be dominant or recessive. 37 Docsity.com Genetics and Heredity page 56 • The allele composition of a plant is the Genotype. 40 Docsity.com Genetics and Heredity page 56 • A common method of predicting the genotypes and phenotypes of offspring is the Punnett Square. 41 Docsity.com Answer these questions 1. A common method for determining phenotypes and genotypes is the? 2. The allele composition of a plant is known as the? 3. What is a homologous chromosome? 4. Meiosis controls formation of which two sex cells? 5. Allelic chromosomes can be of two types, identify them. 42 Docsity.com Plant Breeding page 58 • The production of hybrid seed is managed by production organizations. • Growers are under contract to grow the parent lines and make the hybrids. • Seed production fields must be isolated from other fields to prevent unwanted cross- pollination. 45 Docsity.com Plant Breeding page 58 • When tassels begin to emerge, the female plants are detassled to prevent selt- pollination. • The wind then cross-pollinates the male parent with the female to produce hybrid seed. 46 Docsity.com Plant Breeding page 59 • Inbreeding: the process of crossing two similar parents. • After inbreeding five to seven generations, certain phenotypes will be expressed. 47 Single Cross Inbred parent A x Inbred Parent B Single cross AxB Three Way Cross Inbred parent A x Inbred Parent B Single Cross AxB x Unrelated Inbred C Three-way cross (AxB) x C Docsity.com Biotechnology Techniques • Micropropagation: the propagation (asexual) of plant cells or tissues in a closed container. • Cell culture: modifying the genetic makeup of the cell and then regenerating plants with desired traits. 50 Docsity.com Biotechnology Techniques • Microinjection: the mechanical insertion of genetic material into a single, living cell. • Cell walls can be dissolved using enzymes. • This exposes the cells protoplast. • This allows the genetic makeup of different plants to be fused together. 51 Docsity.com Biotechnology Techniques • Recombinant DNA or genetic engineering involve; 1. Gene splicing 2. Replication 3. Transfer of genes to other organisms Transgenic organisms would carry in their cells a foreign gene. 52 Docsity.com