Plant and Animal Breeding Flashcards
State 4 things breeders look to develop in crops and animals.
- higher food yield
- higher nutritional value
- pest and disease resistance
- ability to thrive in particular environmental conditions
What is the purpose of inbreeding?
Selected related plants/animals are bred for several generations until the population breeds true to the desired type.
What is eliminated by inbreeding?
heterozygotes
What is inbreeding?
Fusion of gametes from 2 close relatives
What is outbreeding?
Fusion of gametes from 2 unrelated members of the same species.
What causes inbreeding depression?
When the genotypes that result are homozygous for an accumulation of recessive, deleterious alleles.
What is the result of inbreeding depression?
Individuals will do less well at surviving to reproduce.
What is an advantage of cross breeding?
Individuals from different breeds may produce a new crossbreed with improved characteristics.
What must be maintained to continually produce crossbreeds?
The two parent breeds
What are the advantages of F1 hybrids in plants?
Usually increased vigour and yield
What is the genetic make-up of the F1 hybrids?
Relatively uniform heterozygous crop
In inbreeding animals and plants, why are F1 hybrids not usually bred together?
The F2 population produced shows too much variation.
What has resulted desirable genes being identified and then used in breeding programmes?
Genome sequencing
How can recombinant DNA technology be used to improve crops?
Where one or more genes are inserted into the genome with improved characteristics.
What is a cultivar?
A plant variety produced from selective breeding
State 3 things field trials are used for.
- Compare the performance of different cultivars under the same conditions
- Compare different treatments on the same cultivars
- evaluate GM crops
State 3 requirements for a field trial.
- change only one thing
- randomisation
- appropriate number of replicates
What is the reason for randomisation?
to prevent bias
Why are several replicates needed in a field trial?
To take account of variability within the sample.
Why is it important only one thing is changed?
So a fair comparison can be made
