HORT exam 1 Flashcards
Plant Breeding Impacts:
Genetic Diversity, Yield, and Nutrition
Camerarius
1694, Germany, sex in plants and pollen necessary for fertilization
Koelreuter
1760-66, Germany hybridization
sterility of tobacco
characteristics by parents pollen and ovules
pass down and make new combinations
AxB or BxA
Extra vigor in F1
Role of insects and wind
Thomas Knight
President of Society of London
used hybridization for practical crop improvement
Shirreff
1857, Scotland use Progeny test
evaluate genotype by offspring performance
Mendel
1865-66, Austria
Book: Experiments in Plant Hybridization
Father of Genetics
Laws of Inheritance
refound 1900
Strasburger
1875-88, germany, describes chromosomes, establishes constancy of chromosome number in plant species; shows reduction - division of chromosomes (mesosis)
Johansen
1903, Denmark
Pure Line Theory
Schull
1909
inbreeding depression in corn
heterosis: vigor of f1 over parents
hybrid corn replace open pollen corn
McClintock (1950)
genes could move on chromosome
Nobel prize for Transposable Elements (1983)
3 ways to enhance biomass:
Improved Seasonal Adaptations
Tolerance to Adverse Environmental Factors (drought, heat, herbicides etc.)
Resistance to Pests (disease insects weeds)
3 Types of Parititon
Vegetative-Reproductive Compensation
Reproductive-Vegetative Compensation
Vegetative-Vegetative Compensation
Vegetative-Vegetative Compensation
occurs with Potato and with the Root Crops (only really want roots)
Reproductive-Vegetative Compensation
flowering and seed fertility are suppressed because they are not used. Example: Cabbage, onion etc. Sometimes causes issues with seed production.
Vegetative-Reproductive Compensation
when product is flower, fruit seed. Plant only grown enough to support reproductive growth and growth of the wanted part.
4 quality characters
Organoleptic: taste, smell, texture, color
Chemical: sugar content of grapes or protein in beans
Mechanical: length, strength, fineness of cotton fibers
Biological: effect of animal feed on animal growth
2 objectives of plants breeding
Yield and Quality
Johansen’s Pure Line Theory:
Heterogeneous population (many genotypes), variation for a given characteristic is due to both genotype and environment
If a single plant is self-fertilized for several generations, its progeny will constitute a ‘pure line’ (true breeding genotype), which is genetically uniform (homogeneous and homozygous)
Variation within a pure line is due to environment only
Selection from a population is only effective insofar as the population is genetically variable
Progeny Test
Made by Louis Leveque de Vilmorin (1856) (France) utilized the progeny test to increase the sugar content of the wild sugar beet. The Progeny Test evaluates the breeding value of a single plant by performance of its progeny.
4 disciplines that impact plant breeding:
Plant biochemistry and molecular biology
Entomology
Pathology
Crop Physiology
3 advantages of molecular markers
Selections made on genotype rather than phenotype which can increase speed and efficiency
DNA can be isolated from nay tissue at any stage
DNA has longer shelf life
3 advantages of transgenic crops
Advantages: Delay ripening and prevent softening, color and flavor, virus resistance, herbicide resistance
economic, and environmental
3 disadvantages of transgenic crops
Disadvantages: Allergens, Antibiotic resistance, Gene flow from crop to week, new gene make up on non target, GM Protein leak into soil, disrupt of ecosystem
Plant Variety Protection Act
(1970) gave intellectual property right protection to developers of sexually produced plants and stimulated seed company interest in self pollinated crops. Revised in 1995 to include some asexual crops like potato.
Examples of breeding crops for improved human health benefits
Golden rice: Beta carotene (for Vitamin A) and iron
Carrot and Tomato : more calcium
