Unit 3 Topic 2 - Plant And Animal Breeding Flashcards
why do farmers use selective breeding?
to produce offspring with improved characteristics to support sustainable food production.
whatare the stages of selective breeding?
- desired characteristics are identified
- Parent organisms showing these characteristics are bred together.
- Offspring with the desired characteristics are bred together to produce the next generation.
- Process repeated continuously over many generations, until all offspring show desired characteristics.
what are the desirable characteristics in plants?
higher yeild, higher nutritional value, pest resistance, disease resistance, usefull physical characteristic, ability to shrive in a particular environment
what are the desirable characteristics in animals?
resistance to bacterial infections, high feed conversion ratios, high fertitlity, ability to thrive in extreme environments
what is a cultivar?
Intentionally bred organisms that have desired characteristics that allow for a population of ‘improved’ animals/plants to be sustained
what is a plant field trial?
experimental investigations that can be set up to compare the performance of two different plant cultivars under similar environmental conditions, investigate the effect of different environmental conditions on a new cultivar of crop plant and evaluate GM crops
how are plant field trials set up?
what is continuous variation?
a phenotype which varies from one extreme to another and can be measured
what is discrete variation?
members of a group can be divided into distinct groups
what is single gene inheritance?
A characteristic that shows discrete variation is normally controlled by alleles of a single gene, the alleles are either dominant or recessive
what are the effects of inbreeding?
loss of heterozygosy and inbreeding depression
what is inbreeding depression?
harmful alleles caused by an increase in the frequency of individuals who are homozygous with recessive alleles, can lead to a decrease in vigour, size, fertility and yield
what is hybrid vigour?
when hybrid offspring fare better with increased vigour, yeild and fertility because weaker recessive alleles are masked by dominant ones
what is genome sequencing?
Genomic sequencing can be used to identify a single gene in an organism that has a desirable characteristic, once the gene has been identified, it can be inserted into the genome of a crop plant or breed of domestic animal through breeding programmes.
