3.2 Criteria Flashcards
Breeders develop crops and animals with what? (4)
- higher food yields
- Higher nutritional values
- Resistance to pests and diseases
- Ability to thrive in particular environmental conditions
Define a cultivar (cultivated variety):
A plant created or selected fro desirable characteristics and can be maintained by cultivation
Plant field trials compare the performance of different what? (3)
- cultivars
- treatments
- GM crops
Plant field trials must what? (3)
- Select treatments to ensure valid comparisons
- Use sufficient replicates to take account of variability within the sample
- Randomise treatments to eliminate bias
Explain the process of inbreeding:
Selecting related plants or animals, and breeding them for several generations until the population breeds true to the desired type due to the elimination of heterozygotes
Inbreeding may result in what?
Inbreeding depressions
What is meant by inbreeding depression?
Where there is an increase in the frequency of individuals who are homozygous for recessive deleterious alleles.
Individuals showing inbreeding depressions are less likely to survive to reproduce due to what? (5)
- reduced vigour
- poor health
- reduced size
- low disease resistance
- may show reduced yeild
Cross breeding introduces new alleles to plant and animal lines by crossing what?
Crossing a cultivar or breed with an individual showing a different desired phenotype
In animals, the new cross breed population shows improved what?
Characteristics
The two parental lines used to produce the improved crossbreeds are maintained to allow what?
Continued production of crossbreeds
In some plants two different inbred lines are crossed to produce F1 hybrids which show?
A uniform hetrozygous crop
F1 hybrids show increased what?(4)
- Increased vigour
- increased disease resistance
- increased growth rates
- increased yield
Genomic sequencing allows individuals carrying desirable to be what?
Identified and then used in breeding programmes
GM crop plants with improved characteristics can be produced by doing what?
Inserting single genes for desirable characteristics into their genomes
GM crops can also produced by using what?
Recombinant DNA technology
Name 2 examples of recombinant DNA technology in plants:
- Insertion of Bt toxin gene for past resistance
- Insertion of glyphosate resistance gene for the herbicide tolerance
