Term
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Definition
- Non-shattering of seeds
- Synchronous flowering
- Larger fruit and seed
- Loss of defensive structures (hair, thorns...)
- Loss of poisonous substances |
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Term
| Planned domestication steps (Lupinus example) |
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Definition
1 - Increase seed size
2 - Elimination of alkaloids
3 - Elimination of pod cracking
4 - Harder seed coat
5 - Elimination of hairs
6 - Elimination of soil water and pH sensitivity
7 - Non-branching |
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Term
| Genetic contribution in Yield |
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Definition
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Term
| Vavilov's Center of Origin and Diversification theory |
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Definition
- Center of origin would have maximum diversity
- Wild relatives can be found in the Centers of Origin
- Center of |
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Term
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Definition
- When a crop is moved, the new population is a subsample of the previous, thus less diverse
- If the new area is more ecological diverse (e.g: mountains), the new population can diversify via natural selection |
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Term
| Importance of Centers of Origin for Breeding |
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Definition
| Sources of genetic variation |
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Term
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Definition
- Domesticated, locally adapted, traditional variety
- Historically maintained by local farmers |
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Term
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Definition
Triticum urartu(AA) x Aegilops speltoides relative (BB) -> Triticum turgidum (AABB)
Triticum turgidum (AABB) x Aegilops tauschii (DD) -> Triticum aestivum (AABBDD) |
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Term
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Definition
- Living tissue from which a plant can be fully recovered
- Seed or tissue culture
- Stored genetic variation
- |
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Term
| Methods of germplasm conservation |
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Definition
| - In situ: conservation of natural habitats and landraces - Ex situ: seed gene banks |
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Term
| Classification of cultivated species |
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Definition
- Commercial varieties: developed by plant breeders. Highly productive.
- Landraces (traditional varieties)
- Breeding lines: intermediate breeding products. Narrow genetic base
- Specific gene stocks: other genetic combinations, like genomic and chromosomal mutants |
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Term
| Classification of wild species (in terms of breeding) |
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Definition
- For direct use: species used by man but not cultivated. E.g. wild pastures
- For indirect use: wild species related to cultivated species, with valuable traits for crosses.
- Potentially utilizable: Not currently use but may have valuable traits. |
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Term
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Definition
- Primary: cultivated species and immediate relatives. Can be easily crossed.
- Secondary: species which transferable genes, but with some difficulty. Progent may be sterile
- Tertiary: crosses requires some special techniques or may not be possible |
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Term
| Canadian Plant Germplasm System (GRIN-CA) |
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Definition
| Network of centres and people dedicated to preserving genetic diversity of crops |
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Term
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Definition
- Sunflowers
- Strawberries
- Saskatoons
- Canola
- Cranberries |
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Term
|
Definition
- Few loci
- Low environmental influence
- Phenotype can be divided into discrete classes |
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Term
|
Definition
- Many loci
- Environmental influence
- Phenotype displays continuous variation (e.g: plant height) |
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Term
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Definition
- Asexual (Bulb, Corm, Tubers, Rhizomes, Stolon, Apomixis)
- Sexual |
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Term
|
Definition
| Asexual form of reproduction that produces fertile seed genetic identical to the maternal plant |
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Term
|
Definition
- Sporophytic: embryo develop from tissues external to embryo sac (adventitious embryony)
- Gametophytic Aposporic: All megaspores degenerate and embryo is develop from aposporous initial cell
- Gametophytic Diplosporic: megaspore mother cell does not undergoes meiosis and embryo is developed via parthenogenesis |
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Term
|
Definition
- Self-pollinated
- Cross-pollinated |
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Term
| Charateristics of Self-Pollinated species |
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Definition
- Often annual
- No inbreeding depression
- Cleistogamy
- Homozygous individuals
- Staminal sheat: Cone of anthers around carpel |
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Term
| Charateristics of Cross-Pollinated species |
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Definition
- Dioecy: separate male and female plants
- Monoecy: separate male and female flowers on same plant
- Protandry: Pollen shed before stigma is mature
- Protogyny: Stigma matures before pollen is shed
- Self-incompatibility: genetic block to selfing |
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Term
| Self-incompatibility mechanisms |
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Definition
- Gametophytic: genotype of pollen determines incompatibility
S1S3 x S1S3 -> no functional gametes
S1S3 x S1S2 -> S2 functional, progeny S1S2 or S3S2
- Sporophytic: genotype of parent determines incompatibility
S1S3 x S2S3 - no functional gametes
S1S3 x S2S4 - only functional combination |
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Term
|
Definition
Difference in inheritance when the maternal and paternal parents are switched
- Mitochondrial -> maternal inheritance
- Plastids -> varies |
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Term
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Definition
| Genetic variance (G) + Environmental variance (E) + Genotype x Envinronment interaction (GxE) |
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Term
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Definition
| Additive variance + Breeding value + Dominance variance + Epistatic variance |
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Term
|
Definition
Proportion of phenotypic variance due to genetic causes
- Broad sense: VG/VP
- Narrow sense: additive proportion (that can be selected) |
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Term
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Definition
Gain obtained by mating selected parents
Mean of progeny - Mean of original population |
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Term
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Definition
| Change in the mean of population due to 1 cycle of selection |
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Term
| Steps in developing self-pollinated cultivar |
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Definition
1 - Choosing objectives
2 - Selection of parents
3 - Formation of segregating populations
4 - Inbreeding adequate levels of homozygosity
5 - Evaluate superior homozygous lines
6 - Preparing seed stocks for maket |
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Term
| How to obtain variability? |
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Definition
- Introducing new populations
- Inducing mutations
- Hybridization (most common) |
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Term
|
Definition
Product of a single self-fertilized plant
- Highly homozygous
- All plants have the same genotype (Homogeneous) |
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Term
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Definition
| Group of plants within a species that are genetically distinct from other groups |
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Term
| Essential characteristic of a cultivar |
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Definition
- Identity: form of recognition. Morphological trait or genetic marker
- Reproducibility: progeny maintains traits |
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Term
|
Definition
1 - Plants are chosen for desirable phenotype
2 - Best phenotypes are selected each cycle
3 - No progeny test
4 - Retains heterozygosity |
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Term
| Pros and Cons of Mass Selection |
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Definition
Pros:
- Simplest, cheapest method
- The residual heterozygosity may confer adaptations
Cons:
- Heterogeneous populations
- May not qualify for cultivar |
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Term
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Definition
Superior types are selected and a record of descent is made for each generation.
Individuals within families are selected. |
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Term
| Pros and Cons of Pedigree method |
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Definition
Pros:
- Inferior and duplicate families can be discarded in early generations
- The record of descent allows the certification of cultivars
Cons:
- May narrow variability quicker
- More time consuming and costly than Mass and Bulk |
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Term
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Definition
No selection is made in early generations (~F5). And seed sowed in each generation is a sample of the previous generation
This allows natural selection to occur weeding out weaker types |
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Term
| Pros and cons of Bulk Method |
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Definition
Pros:
- Saves time and labour at early gens
- Natural selection can promote locally adapted types
- More crosses can be handled
Cons:
- Natural selection may act against breeding goals
- The adapted lines may be all closely related |
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Term
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Definition
Advances homozygosity without selection (up to ~F5-F6)
One seed per plant is harvested to perpetuate next generation
Selection is performed from F6 and on |
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Term
|
Definition
Pros:
- The early generations can be plant in different environments unrelated to where the segregates will be grown
- Easy way to rapidly inbreed a population
- Natural selection doesn't affect populations
Cons:
- Cannot make use of natural selection
- Genetic combination may be lost if populations are too small |
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Term
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Definition
Quickest approach to homozygosity (immediate production of pure lines)
- Ovary or anther culture to produce haploids
- Duplication with colchicine |
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Term
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Definition
Repeated crossing of hybrid progeny to the same variety
- Used to introgress genes
- Does not allow new combinations
- Linkage drag may be a problem |
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Term
| Multiple Parent Strategies |
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Definition
- Convergent (Pyramid) cross
1x2, 3x4, 5x6, 7x8
12x34, 56x78...
- Chain cross:
1x2,2x3,3x4...
- Conical cross:
Good for cytoplasm inheritance |
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Term
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Definition
Failure of a plant to produce pollen
May be genetic engineered to facilitated crosses, without the need for emasculation |
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Term
| RIPE: Recurrent Introgressive Population Enrichment (Male-sterile facilitated) |
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Definition
msg6 gene for male-sterility is closely linked to sex1 locus. Shrunken seed produces male-sterile plants.
Elite-level plants (E) are male-sterile. A population is introduced and crossed with E plants through progressive introgression.
There are 4 levels: Base (50% E), Intermediate (75% E), High (87.5% E) and Elite plants, which are 93.25%, retaining 7% of new genetic material |
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Term
|
Definition
Population: 2AA 4Aa 2aa
f(A) = (2x2+4x1+2x0)/16
f(A) = 0.5 or square root of 0.25 (AA frequency: 2/8) |
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Term
| Selection before pollination |
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Definition
Eliminate inferior plants before pollination, so they will not contribute with pollen
- Gains are doubled |
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Term
| Methods for selecting two traits |
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Definition
- Tandem selection: one trait improved first (C0-C5) then the other trait (C6-C10)
- Independent Culling: two traits selects simultaneously. Plot performance with 1 trait per axis.
- Selection index: formula using both traits is develop and used as base for selection |
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Term
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Definition
| Repeated cycles of selection and intermating to improve the frequency of favorable alleles in a population |
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Term
| Recurrent Selection Methods |
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Definition
- Phenotypic: selection of best performing individuals
- Half-sib family: Seed from the same plant share the same mother
- Full-sib family: Control of parents
- S1 Family: product of cross |
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Term
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Definition
| Loss of vigor associated to increase in homozygosity |
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Term
|
Definition
| Increased vigor due to heterozygosity |
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Term
|
Definition
Developing of a homogeneous population of plants from crossing inbred lines
- Heterozygous plants
- Homogeneous populations |
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Term
| Genetic basis of Heterosis |
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Definition
- Dominance theory
- Overdominance theory
- Presence/Absence theory |
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Term
|
Definition
1 - Develop segregation population
2 - Inbreed population with selection
3 - Evaluate line perfomance
- General combining ability
- Specific combining ability
4 - Evaluation of potential commercial hybrids |
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Term
| General combining ability |
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Definition
| Considers the average performance of the progeny of individual inbreds when mated with a genetic diverse population |
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Term
| Recurrent Selection for GCA |
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Definition
| Recurrent selection with General combining ability as a trait |
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Term
| Reciprocal Recurrent Selection |
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Definition
| Recurrent selection to increase frequencies of alleles in two populations that will be crossed to produce hybrids |
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Term
|
Definition
Single cross hybrids:
Inb 1 x Inb 2 -> F1 Hybrid
Double cross hybrid
Inb 1 x Inb 2 -> F1
Inb 3 x Inb 4 -> F1
F1 x F1 -> DC hybrid |
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Term
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Definition
Cytoplasmatic: Sterile (rr) x Fertile (RR) -> Progeny 1/4 Sterile (rr) Mendelian segregation
Nuclear: Maternal cytoplasm -> Progeny 100% sterile |
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Term
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Definition
| DNA sequence associated with a location in a genome |
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Term
| Steps for Marked Assisted Selection |
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Definition
1 - Develop molecular marker map
2 - Establish linkages between markers and loci controlling trait
3 - Cross and develop segregating population
4 - Genotype breeding population
5 - Predict phenotype based on markers
6 - Select molecular marker genotypes |
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Term
|
Definition
Single Nucleotide Polymorphisms
Most used molecular marker |
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Term
| Methods for controlling disease |
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Definition
1 - Resistant cultivars
2 - Crop rotation
3 - Avoid monoculture
4 - Biological control
5 - Pesticides |
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Term
|
Definition
Ability of host plant to prevent any multiplication of the pathogen
- Very rare |
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Term
|
Definition
| Cultivar develops disease but have no significant yield reduction |
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Term
|
Definition
| Pure lines with resistance genes, used to differentiate pathogen classes |
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