Plant & Animal breeding Flashcards
What is the purpose of plant and animal breeding?
To improve characteristics to help support sustainable food production.
What are some desirable characteristics for plants and animals?
- higher food yields
- higher nutritional values
- pest and disease resistance
- ability to thrive in particular environmental conditions
What are plant field trials?
Plant field trials are carried out in a range of environments to compare the performance of different cultivars or treatments and to evaluate GM crops.
What factors have to be taken into account when designing field trials?
- selection of treatments
- number of replicates
- randomisation of treatments
What does ‘selection treatments’ mean when designing field trials?
To ensure valid comparisons.
What does ‘number of replicates’ mean when designing field trials?
To take account of the variability within the sample.
What does ‘inbreeding’ mean?
Selected related plants or animals are bred for several generations until the population breeds true to the desired type due to the elimination of heterozygotes
How does ‘inbreeding depression’ occur?
Inbreeding can result in an increase in the frequency of individuals who are homozygous for recessive deleterious alleles. These individuals will do less well are surviving to reproduce, resulting in inbreeding depression
How can you analyse the patterns of inheritance in inbreeding?
Monohybrid crosses.
How does a crossbreed with improved characteristics comes about?
In animals, individuals from different breeds breeds may produce a new crossbreed populations with improved characteristics. The two parent breeds can be maintained to produce more crossbred animals showing the improved characteristic.
How can new alleles be introduced to a plant or animal?
By crossing a cultivar or breed with an individual with a different, desired genotype.
In plants, describe F1 hybrids?
In plants, F1 hybrids, produced by the crossing of two different inbred lines, create a relatively uniform heterozygous crop. F1 hybrids often have an increased vigour and yield.
Describe plants with an increased vigour?
Plants with an increased vigour may have an increased disease resistance or increased growth rate.
When inbreeding with plants and animals, why should F1 hybrids not be bred?
As the F2 produced shows too much variation.
How can organisms with desirable genes be identified?
Due to genomic sequencing, organisms with desirable genes can be identified and then used in breeding programmes.
