3.2 Plant and Animal Breeding Flashcards
(30 cards)
Why do humans create new plant and animal varities?
To improve characteristics
This also helps with supporting sustainable food production
Give four examples of improved characteristics desired during plant/animal breeding
- Higher food yields
- Higher nutritional values
- Pest and disease resistance
- Ability to thrive in particular environmental conditions.
Define ‘field trial’
a type of investigation to figure out various aspects of a crop
Give examples of what a field trial may be used to figure out
- The effect of different environmental conditions on a new cultivar.
- Compare the performance of different plant cultivars.
- Compare the effect of different treatments (e.g. fertilisers or pesticide).
- Evaluate genetically modified (GM) crops.
List the three design features that need to be considered during field trials
- Randomisation of treatments
- Number of replicates
- Selection of treatments
Explain why randomisation of treatments needs to be considered when designing a field trial
To eliminate bias when measuring treatment effects
Bias = deviation from the true result
Explain why number of replicates needs to be considered when designing a field trial
To take account of variability within a sample and increase reliability
Explain why selection of treatments needs to be considered when designing a field trial
To ensure valid comparison
Define ‘inbreeding’
Genetically related plants or animals are bred together
Define ‘outbreeding’
Genetically unrelated plants or animals are bred together
Define ‘allele’
Different form of a gene
e.g. the gene for hair colour has alleles for brown and black
Define ‘genotype’
The alleles that are present, written as letters
e.g. BB or Bb or bb
Define ‘phenotype’
What the characteristic actually looks like
e.g. brown hair
Define ‘homozygous’
Only one type of allele is present in the genotype
e.g. BB or bb
Define ‘Heterozgous’
Both dominant and recessive alleles are present in the genotype
e.g. Bb
Define ‘dominant’
An allele that will always be seen in the phenotype if it is present
Define ‘recessive’
An allele which will only be seen in the phenotype if there is no dominant allele present
Describe the impact inbreeding has upon how heterozygous a population is
The population will become more homozygous
Explain why inbreeding is used during selective breeding programmes
By eliminating heterzygous alleles the organism is more likely to breed true to the desired type
e.g. population will consistently give you the desired characteristic(s)
Describe the cost of inbreeding
Causes an increase in the frequency of individuals who are homozygous for recessive deleterious alleles.
These individuals will do less well at surviving to reproduce
deleterious = harmful
Define ‘inbreeding depression’
The reduced chance of survival due to mating between genetically related individuals.
Define ‘crossbreeding’
The breeding of individuals from different breeds to produce a new crossbreed population with (potentially) improved characteristics.
How can new alleles be introduced into plant and animal lines?
By crossing a cultivar or breed with an individual possessing a different, desired genotype
What is an F1 hybrid?
The offspring produced from the crossing of two different cultivars or breeds
