3.2 Plant and Animal Breeding Flashcards
What characteristics do breeders develop crops and animals to have?
- higher food yields
- higher nutritional values
- pest and disease resistance
- ability to thrive in particular environmental conditions
Why are plants and animals bred to improve characteristics?
to help support sustainable food production
Why and wherare plant field trials carried out?
- to compare the performance of different cultivars or treatments and to evaluate GM crops
- in a range of environments
What has to be taken into account when designing field trials?
- selection of treatments
- the number of replicates
- the randomisation of treatments
Why does the section of treatments have to be taken into account when deigning plant field trails?
to ensure valid comparisons
Why does the number of replicates have to be taken into account when designing plant field trials?
take account of the variability within the sample
Why does the randomisation of treatments have to be taken into account when designing plant field trails?
to eliminate bias when measuring treatment effects
What is inbreeding?
- selected related plants or animals
- are bred for several generations
- until the population breeds true to the desired type
- due to the elimination of hetrozygotes
What can happen as a result of inbreeding?
- increase in the frequency of individuals who are homozygous for receive deleterious alleles
- do less well at surviving to reproduce
- resulting in inbreeding depression
What is crossbreeding?
- new alleles can be introduced to plant and animal lines
- by crossing a cultivar or breed with an individual with a different, desired genotype
What may happen as a result of cross breeding?
- individuals from different breeds may produce a new crossbreed population with improved characteristics
- two parent breeds can be maintained to produce more crossbred animals showing the improved characteristic
What are the effects of crossbreeding?
- increased vigour
- increased disease resistance
- increased growth rate
Why are F1 generations not usually inbred together?
the F2 produced shows too much variation
What can happen as a result of genome sequencing?
organisms with desirable genes can be identified and then used in breeding programs
How are genetically modified plants created?
single genes for desirable characteristics are inserted into the genomes of crop plants, creating genetically modified plants with improved characteristics
