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28 Cards in this Set

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Variation that can divide members of a species into two or more distinct groups

Discrete variation

Three characteristics breeders would select to produce improved breeds/cultivars

Increase in yield


Disease resistance


Ability to thrive in a particular environment

A diagram to show the probability of the inheritance of characteristics of a single gene

Monohybrid cross

Phenotype

The observed inherited characteristics

Genotype

The combination of alleles inherited

A method for identifying an organism with an unknown genotype by crossing it with a organism that is homozygous recessive for that trait.

Test cross

Variation that shows a range of variants from one extreme to another

Continuous variation

The type of pattern shown when continuous variation is plotted on a distribution curve

Normal distribution (bell shaped curve)

Characteristics controlled by an interaction by alleles of more than one gene

Polygenic

A large scale investigation into how environmental factors affect the growth of crops

Field trial

In a field trial how is bias eliminated?

Randomising treatments (making sure replicated treatments are not applied in a pattern)

How is reliability ensured in a field trial?

A number of replicates are set up

How do researchers ensure fair comparisons can be made between treatments in a field trial?

A selection of treatments are applied and no other factor is varied.

Why is it important to repeat field trials in different environments?

So that a more detailed conclusion can be drawn e.g. Specifically which climates a crop grows best in.

The fusion of two gametes from close relatives of the same species.

Inbreeding

The fusion of two gametes from unrelated members of the same species.

Outbreeding

The pollination of a flower with pollen from the same flower/plant

Self pollination

Fertilisation of a plant ovule with pollen from another plant

Cross pollination

Mechanisms cross pollinating plants have to prevent self pollination

Anthers and ovaries maturing at different times.

The accumulation of recessive alleles for deleterious genes

Inbreeding depression

The effects of inbreeding depression on an organisms phenotype

Decline in vigour


Lower yield


Loss of fertility

A method for introducing new alleles to an inbred plant or animal.

Cross breeding

An individual resulting from a cross between two genetically dissimilar parents of the same species

F1 Hybrid

In an F1 hybrid what genotypic ratio do the F1 generation have?

They are all heterozygous

What is hybrid vigour

F1 hybrid species show increased vigour, yield and fertility.

What techniques can be used to maintain the F1 hybrid genotype?

Back crossing the F1 hybrid with a parental breed and selection to remove weaker animals.


Maintain the parental generation to continually cross them.

What modern technique can be used to identify organisms that possess alleles of a gene for a desirable characteristic?

Genome sequencing

What modern technique can be used to improve a species by introducing desirable genes?

Genetic engineering