Unit 3 Key area 2 Flashcards
State two reasons why a field trial may be carried out?
A field trial can be carried out to
- compare the performances of different cultivars
- evaluate different GM crops
State the three factors that must be taken into consideration when we are designing a field trial?
- Number of replicates
- Selection of treatments
- Randomisation of treatments
Explain why selection of treatments must be taken into account when designing a field trial?
Selection of treatments must be taken into account to ensure that valid comparisons are made
Why must number of replicates be taken into account when we are designing a field trial?
Number of replicates is required to take into account the variability within the sample
Why must randomisation of treatments be taken into account when designing a field trial?
Randomisation of treatments eliminates bias when measuring treatment effects.
Explain what is meant by the term “inbreeding”?
Inbreeding is what happens when selected animals or plants are bred for several generations until the population breeds true to the desired trait as a result of the elimination of heterozygotes.
Explain what is meant by the term inbreeding depression?
Inbreeding depression describes the phenomenon of an increase in the frequency of individuals that are homozygous for recessive deleterious alleles. These individuals will be put at a disadvantage as a result of the deleterious alleles and will not do as well at surviving to reproduce.
Explain how new alleles can be introduced into a plant or animal line?
New alleles can be introduced into a line by crossbreeding in which a cultivar or organism is bred with an individual of a different desired genotype
What happens if there is success in cross breeding?
The two parent breeds should both be maintained so that there can be a continued production of the crossbreed displaying the improved characteristic.
Describe the effects that a plant having increased vigour can have?
A plant that has increased vigour have:
- Increased resistance to disease
- Increased rate of growth
Why are F1 generations of plants and animals not typically bred together?
As the resulting F2 generation produced will display too much variation for the desired traits (remember the punnett square)
Describe how genetic sequencing can be used in breeding programs?
Using genetic sequencing animal breeders can identify individuals with desired genes and use them in breeding programs.
Breeding programs can also involve plants that have been genetically modified using recombinant DNA technology.
State two examples of recombinant DNA technology that is typically used in plants?
- BT toxin is a gene that is commonly inserted into cultivars as it provides pest resistance
- Glyphosate gives the plant herbicide resistance allowing herbicides to be used to reduce competition
