Chapter 4 - Plant Genotype (PPT) Flashcards
Genetic Improvements
- facilitate harvest
- pest and disease resistance
- tolerance to environmental stresses
- better flowers/colors of flowers
- better flavor
- increased nutritional value
DNA
genes that control an organism
RNA
genetic material that makes proteins, using DNA as the template
Mitosis
splitting a cell into 2 identical daughter cells
Meiosis
formation of games with half the number of normal chromosomes
Haploid (n)
half the number of normal chromosomes (single genes)
Diploid (2n)
normal number of chromosomes (pairs)
Triploid (3n)
an extra set of chromosomes (3 single per group)
Tetraploid (4n)
two extra sets of chromosomes (4 single per group)
Polyploidy
3n, 4n, 5n, 6n, 7n, 8n, 9n, etc. multiple chromosomes in sets
-makes more vigorous, productive plants
Fertilization
-sperm nucleus from pollen unites with ovule in ovary to form embryo
Double Fertilization
- only happens w/ Angiosperms
- second sperm nucleus from pollen unites with other tissues in the ovary to make endosperm (3n)
Heritability
F1: first cross (hybrid)
F2: cross of two F1s
Homozygous
both alleles are the same
Heterozygous
each allele is different
Cloning Plants
Propagated asexually (without fertilization) - no recombination of genes -Done w/ cuttings, layering, grafting, or tissue culture
Heterosis
- Hybrid vigor: increase in size or vigor over either of the parents
- Inbreeding depression: two many recessive alleles causes problems
GMOs
-not common in horticultural crops at this point
Cross-Fertilization
-Dioecy in plants helps with cross-fertilization or cross-breeding
Cross-Fertilization Incompatibility
- some fruit trees cannot pollinate their own species
- pollinizer: different tree that can fertilize the first species
- pollinator: bee or insect that moves pollen around
- Almonds, plums, sweet cherries, pears, apples and hazelnuts all need a pollinator
- Benefit: ensures genetic variability for adaptation
Cross-Fertilization Dichogamy
-Male and female parts develop at different times (forces cross-fertilization)
Cross-Fertilization Xenia
- Corn
- Cross-fertilization has an immediate effect on the ears
- Separate types of corn by about 1 mile or by 2 weeks in time
- Varied fruit colors
Resistance
- variation in gene pool can allow some individuals to be resistant to a pest/pathogen
- can select and multiply those genes
- GOOD
- Applying too strong of selection pressure can lead to resistance (insect resistant to a pesticide, weed resistant to an herbicide)
- BAD
-ROTATING MODES OF ACTION is KEY!!
