Key Area 2-Plant And Animal Breeding For Sustainable Production Flashcards
Why might plant and animal breeders want to manipulate hereditary?
- improve plant crops
- improve animal stock
- have a more sustainable production
What are four characteristics selected for in crops and animals?
- higher yield
- higher nutritional values
- pest/disease resistance
- ability to thrive in particular environments
Why would a plant field trial be carried out?
- compare performance of two different cultivars under the same environmental conditions
- find out the effect of different environmental conditions on a new cultivar if a crop plant
- evaluate GM crops
What must be considered when field trials are designed?
- treatments selected must ensure a fair comparison using the same sample size for validity
- the number of replicates must be enough to account for variability within samples
- randomisation of treatments eliminates bias when measuring treatment effects
What is outbreeding?
When two unrelated individuals cross-breed via the fusion of gametes
What are two organisms that are naturally outbreeding?
Animals
Cross-pollinating plants
What is inbreeding?
The fusion of gametes from close relatives (or self-pollination in the case of flowers)
What is an inbreeding depression?
An increase in the change of becoming double recessive for an undesirable trait
How can inbreeding depressions be avoided in self-pollinated plants and outbreeding species?
- self-pollinating plants: deleterious genes will have been eliminated through natural selection
- outbreeding: outbreeding where the desirable trait is selected for but all other traits remain diverse
What is cross breeding?
The process of creating a hybrid organism through sexual reproduction of two parent organisms
Why is cross breeding beneficial?
It introduces new alleles into the next generation and can provide an F1 population with improved characteristics
What is a backcross?
Backcrossing is the process of maintaining the desired characteristic of the F1 population by breeding F1 with the parent organism or an individual with the same genotype as the parent
How can a new breed be maintained?
- backcrossing with the parent
- maintaining the parent generation to breed
Are F1 hybrids uniformly heterozygous or homozygous?
Uniformly-heterozygous
How is the yield of F1 population?
They show increased yield or other improved characteristics and this is known as hybrid vigour
