PLANT AND ANIMAL BREEDING U3 Flashcards
State the function of plant and animal breeding and the characteristics that breeders develop
Plant and animal breeding are used to improve characteristics to help support sustainable food production.
Breeders develop crops and animals with:
higher food yields
higher nutritional values
pest resistance
disease resistance
ability to thrive in particular environmental conditions
Describe a plant field trial and explain the factors taken into account when designing field trials
Plant field trials are carried out in a range of environments to compare the performance of different cultivars (plant selected for with a desirable characteristic) or treatments and to evaluate GM crops.
When designing field trials account has to be taken into account of selection of treatments, the number of replicates and the randomisation of treatments.
Selection of treatments - to ensure valid comparisons.
Randomisation of treatments - to eliminate bias when measuring treatment effects.
Number of replicates - to take into account of the variability within the sample.
State the meaning of the term ‘inbreeding’ and explain the result of inbreeding using the term ‘inbreeding depression’
In inbreeding, selected related plants or animals are bred for several generations until the population breeds true to the desired type (characteristic) due to the elimination of heterozygotes.
As a result of inbreeding can be an increase in the frequency of individuals who are homozygous for recessive deleterious alleles.
These individuals will do less well at surviving and to reproduce. This results in an inbreeding depression.
State the meaning of the term ‘cross breeding’ in plant and animal breeding
In animals, individuals from different breeds may produce a new crossbreed population with desired characteristics. The two parent breeds are maintained to produce more crossbred animals showing the improved characteristic.
New alleles can be introduced to plant and animal lines by crossing a cultivar or breed with a different desired genotype.
Describe why F1 hybrid in plants and F1 hybrids are not bred together
F1 hybrids in plants are produced by the crossing of two different inbred lines to create a relatively uniform heterozygous crop.
F1 hybrids often have increased vigour and yield. Plants with increased vigour may have increased disease resistance or increased growth rate.
When inbreeding animals and plants, F1 hybrids are not usually bred together as the F2 produced show too much variation.
State how genomic sequencing is used in breeding programmes
Organisms with desirable genes can be identified and then used in breeding programmes.
Examples can include higher yielding and disease resistance.
Describe how genetically modified crops are produced and give examples of characteristics used in breeding programmes
Breeding programmes can involve crop plants that have been genetically modified using recombinant DNA technology.
Single genes for desirable characteristics can be inserted into the genomes of crop plants, creating genetically modified plants with improved characteristics.
Recombinant DNA technology in plant breeding includes:
Insertion of Bt toxin gene into plants for pest resistance.
Glyphosate resistance inserted for herbicide tolerance.
