plant and anima breeding 2

• Plant and animal breeding

  • Used to improve characteristics to help support sustainable food production
• Characteristics breeders develop in crops and animals

  • Higher food yields
  • Higher nutritional values
  • Pest resistance
  • Disease resistance
  • Ability to thrive in particular environmental conditions
• Plant field trials

  1. Carried out in a range of environments

  2. Compare the performance of different cultivars or treatments

  3. Evaluate GM crops
• Designing field trials

  • Selection of treatments
  • Randomisation of treatments
  • Number of replicates
• 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
• Inbreeding

  1. Selected related plants or animals are bred for several generations

  2. Population breeds true to the desired type (characteristic)

  3. Elimination of heterozygotes
• As a result of inbreeding

  Increase in the frequency of individuals who are homozygous for recessive deleterious alleles
• Inbreeding depression

  Result of inbreeding
• Crossbreeding in animals

  1. Individuals from different breeds produce a new crossbreed population with desired characteristics

  2. The two parent breeds are maintained to produce more crossbred animals showing the improved characteristic
• Introducing new alleles to plant and animal lines

  Crossing a cultivar or breed with a different desired genotype
• F1 hybrids in plants

  Produced by the crossing of two different inbred lines to create a relatively uniform heterozygous crop
• F1 hybrids

  • Often have increased vigour and yield
  • 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
• Desirable genes in organisms that can be used in breeding programmes

  • Higher yielding
  • Disease resistance
• Breeding programmes can involve crop plants that have been genetically modified using recombinant DNA technology
• Recombinant DNA technology in plant breeding


  • Insertion of Bt toxin gene into plants for pest resistance
  • Glyphosate resistance inserted for herbicide tolerance