Discuss the advantages and disadvantages of genetically modified crops, and explain the process of creating Bt maize.

Here are the answers for Activity 5.9:

5.9.1. Two potential benefits of this genetically modified (GM) crop are:

• Reduced crop damage from the maize stalk borer.
• Increased crop yield due to effective pest resistance.
• Reduced need for chemical pesticides.

5.9.2. Two negative effects of GM crops on the environment are:

• The potential for target pests to develop resistance to the Bt toxin.
• The possibility of harm to non-target organisms (e.g., beneficial insects) that consume the GM plant or its pollen.
• The risk of gene flow to wild relatives, potentially creating herbicide-resistant superweeds.

5.9.3. The technique of using a bacterium to modify maize plants genetically involves:

• The desired Bt toxin gene is isolated from the bacterium Bacillus thuringiensis.
• This gene is then inserted into a Ti plasmid (tumor-inducing plasmid) of another bacterium, Agrobacterium tumefaciens, creating a recombinant plasmid.
• The Agrobacterium carrying the recombinant plasmid is used to infect maize plant cells, transferring the Bt gene into the maize plant's DNA.
• The transformed maize cells are then cultured to regenerate whole maize plants that express the Bt toxin.

5.9.4.

a) The technique illustrated is Microinjection.

b) Two advantages of the genetically modified maize (Bt maize) for the farmer are:

• Higher crop yields due to effective protection against the maize stalk borer.
• Reduced production costs as there is less need for expensive chemical pesticides and associated labor.

c) Two socio-economic implications that plants produced from genetic modification techniques have for the farmer are:

• Increased income for farmers due to higher yields and reduced input costs (e.g., pesticides).
• Improved food security for the farmer and the community, as crops are more resilient to pests and yield more reliably.
• Potential for reduced health risks for farmers due to less exposure to chemical pesticides.