Plant breeding lecture 2

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  1. What are the different types of flowers?
    • Complete-has all major reproductive parts
    • Incomplete-missing reproductive parts (petals)
    • Perfect-has both stamen and pistil
    • Imperfect-unisexual flower
    • Monoecious-contains staminate and pistillate
    • flowers on same plant—Corn
    • Dioecious-contains staminate and pistillate
    • plants—Papaya
  2. What is pollination?
    transfer of pollen grains from the anther to the stigma of a flower
  3. What are the types of pollination?
    • Self-pollinated-accept pollen primarily from
    • the anthers of the same flower
    • Cross-pollinated-accept pollen from different
    • sources
  4. What are the types of self-pollination?
    • Cleistogamy-flower fails to open
    • Chasmogamy-flower opens only after self-pollination has occurred
  5. What are the effects of self-pollination?
    • Highest degree of inbreeding—promotes
    • homozygosity
    • Heterozygosity rapidly eliminated
    • Progeny of a single plant are homogeneous
    • Restricts creation of new gene combinations
    • Mutations are readily exposed through
    • homozygosity
    • Identify one superior genotype and multiply it for sufficient seed
  6. What are the types of cross-pollination:
    • Dioecy-must accept pollen from another
    • source plant—i.e. pollinator row
    • Monoecy-can self pollinate but high
    • percentage of cross pollination allowed
    • Dichogamy-cross-pollination enforced due
    • to maturity differences in stamen/pistil
    • Self-incompatibility-stigma does not accept
    • pollen from its own flower
  7. What are characteristics of cross-pollination:
    • Characterized by heterozygosity
    • Share a wide gene pool and new gene
    • combinations
    • Inbreeding depression occurs—
    • deleterious alleles are no longer masked
    • by heterozygosity
    • Hybrid vigor—increase of vigor of the
    • hybrid over either parental line
  8. What are the types of vegetative propagation?
    • Cuttings—stem, root, leaf
    • Clonal—tuber, stolon, rhizome
    • Tissue Culture—regenerated from a small
    • piece of vegetative material
  9. What are characteristics of vegetative propagation?
    • Genetics fixed clonally—quick process
    • Fertility of plant not an issue
    • Hybrid vigor is fixed in line
    • More difficult to obtain sufficient sources
    • for propagation
    • Highly heterozygous
  10. What is apomixis?
    • Ability of a plant to develop seed without
    • fertilization
    • The asexual reproduction of seed—no new
    • recombination
  11. What are the benefits of apomixis?
    • By cloning plants through seed, hybrid
    • plants can retain hybrid advantage through
    • the hybrid seed
    • Quickly fix superior gene combinations
    • Accelerates plant breeding efforts
    • Producers can save seed year after year
  12. What are the types of pollination control?
    • Mechanical—manually removing anthers
    • (wheat) or using a machine (corn)
    • Chemical—chemicals that induce male sterility in plants
    • Genetic—male sterility or self-incompatibility
  13. Sexual vs asexual reproduction:
    • Sexual Reproduction -- allows genetic
    • recombination and segregation -- genetic
    • variation
    • Asexual Reproduction -- usually and
    • theoretically progeny are identical to the parent plant -- fixing hybrid vigor (heterosis)
    • Mutations occur and are exploited differently
    • based on reproductive method
  14. What is plant breeding?
    • Genetically manipulating plants to suit our needs
    • Objective: Recover the best
    • combination of genes for all important
    • characteristics in one individual
  15. What are the requirements for traditional plant breeding?
    • Hybridization: cross (mate) genetically distinct
    • plants
    • Segregation: distribution of genes to gametes
    • (egg and pollen) via meiosis
    • Recombination: formation of new
    • combinations of genes in offspring
    • Selection: find an individual with the best
    • combination of genes for all important
    • characteristics
  16. What two key concepts are essential for
    successful plant breeding?
    • generating genetic variation
    • selecting on genetic variation
  17. Name three groups who help determine
    plant breeding goals
    • Producers needs
    • End-users needs
    • Environmental needs
  18. What is Euploidy?
    Multiples of whole genomes + / -
  19. What is Anueploidy?
    Multiples of chromosomes of less than whole genomes  + / -
  20. What are germ cells?
    or gametes, are haploid and contain only one set of chromosomes, consisting of one member of each of the pairs
  21. What are euploidy concepts?
    • n = gametic cell chromosome number
    • 2n = somatic cell chromosome number
    • x = number of chromosomes in a set
    • 2x = number of sets of chromosomes
  22. Example Potato: Tetraploid with 48 chromosomes
    • n = 24
    • 2n = 48
    • x = 12
    • 4x = 48
  23. What is Autoploidy or Autopolyploidy (e.g., AAAA)?
    • Duplication of the genome of a given species
    • Via unreduced gametes (meiotic error) or
    • spontaneous doubling of chromosomes
  24. What is Alloploidy or Allopolyploidy (e.g., AABB)?
    • Combination of genomes from two or more
    • species via interspecific hybridization
  25. How does one induce a polyploid?
    • Autopolyploids - Treat seeds/seedlings with
    • Colchicine to double chromosomes
    • Colchicine is derived from autumn crocus
    • (Colchicum autinale). Colcemid is a synthetic
    • equivalent.
    • Alkaloid that disrupts spindle fibers and prevents
    • chromosome migration to poles in mitosis
  26. Allopolyploids continued:
    • Plants with two or more genomes from
    • different but related species
    • Equivalent chromosomes are similar
    • between/among the different genomes
    • Homoeologous Chromosomes
    • in the Triticeae Chromosome:
    • 1A  1B  1D  1R  7H (barley) etc.
  27. Anueploidy EXAMPLES
    • ‘Normal’ Disomic 2n
    •  Some Anueploid Types - Chr. Additions
    •  Primary Trisomics 2n + 1A
    •  Tetrasomics 2n + 2A
    •  In Polyploids - Chr. Deletions
    •  Monosomics 2n - 1A
    •  Nullisomics 2n – 2A
    •  Nulli-Tetrasomics 2n – 2A + 2B
  28. Why are aneuploidies used?
    • Locate a Qualitative Trait Gene to
    • Chromosome
    • Gene or Chromosome Transfer (intra- or
    • interspecific)
    • Establish Homoeologous Groups

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Author:
wsucoug12
ID:
314258
Filename:
Plant breeding lecture 2
Updated:
2016-02-03 05:34:03
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Plant breeding lecture
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Plant Breeding
Description:
Plant breeding lecture 2
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