The flashcards below were created by user
on FreezingBlue Flashcards.
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
What is pollination?
transfer of pollen grains from the anther to the stigma of a flower
What are the types of pollination?
- Self-pollinated-accept pollen primarily from
- the anthers of the same flower
- Cross-pollinated-accept pollen from different
What are the types of self-pollination?
- Cleistogamy-flower fails to open
- Chasmogamy-flower opens only after self-pollination has occurred
What are the effects of self-pollination?
- Highest degree of inbreeding—promotes
- Heterozygosity rapidly eliminated
- Progeny of a single plant are homogeneous
- Restricts creation of new gene combinations
- Mutations are readily exposed through
- Identify one superior genotype and multiply it for sufficient seed
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
What are characteristics of cross-pollination:
- Characterized by heterozygosity
- Share a wide gene pool and new gene
- Inbreeding depression occurs—
- deleterious alleles are no longer masked
- by heterozygosity
- Hybrid vigor—increase of vigor of the
- hybrid over either parental line
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
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
What is apomixis?
- Ability of a plant to develop seed without
- The asexual reproduction of seed—no new
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
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
Sexual vs asexual reproduction:
- Sexual Reproduction -- allows genetic
- recombination and segregation -- genetic
- 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
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
What are the requirements for traditional plant breeding?
- Hybridization: cross (mate) genetically distinct
- 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
What two key concepts are essential for
successful plant breeding?
- generating genetic variation
- selecting on genetic variation
Name three groups who help determine
plant breeding goals
- Producers needs
- End-users needs
- Environmental needs
What is Euploidy?
Multiples of whole genomes + / -
What is Anueploidy?
Multiples of chromosomes of less than whole genomes + / -
What are germ cells?
or gametes, are haploid and contain only one set of chromosomes, consisting of one member of each of the pairs
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
Example Potato: Tetraploid with 48 chromosomes
- n = 24
- 2n = 48
- x = 12
- 4x = 48
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
What is Alloploidy or Allopolyploidy (e.g., AABB)?
- Combination of genomes from two or more
- species via interspecific hybridization
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
- Alkaloid that disrupts spindle fibers and prevents
- chromosome migration to poles in mitosis
- 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.
- ‘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
Why are aneuploidies used?
- Locate a Qualitative Trait Gene to
- Gene or Chromosome Transfer (intra- or
- Establish Homoeologous Groups