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19.3 Genetically Modified Organisms in Agriculture

Syllabus
9700–2028–2029
Topic
19.3
Level
A2

GM traits can raise usable food output or quality

Genetic engineering can help meet food demand by giving farmed animals or crops a defined trait that increases productivity, reduces losses or improves the quality of the food produced.

Improvement route Trait effect Food-demand consequence
Faster or more efficient growth more biomass or marketable product is produced in a given time shorter production cycles or greater output
Resistance to pests, disease or competition fewer animals/plants or less tissue are lost before harvest a larger fraction of potential yield reaches consumers
Tolerance of a farm-management treatment the crop survives while weeds or another limiting factor are controlled reduced competition and higher crop yield
Improved product quality nutritional content, composition, storage life or processing quality is improved more useful or longer-lasting food from the harvest

The causal chain must be explicit: engineered gene → expressed protein/trait → changed growth, survival or product quality → changed usable yield. Benefits are greatest when the trait addresses a real local limitation and is combined with appropriate husbandry, crop management and access to food distribution.

Genetic engineering is a method, not a guarantee of more or better food. Yield can still be limited by water, minerals, climate, disease, management, cost and access; resistance may evolve and ecological effects may reduce long-term benefit.

Three GM examples use different routes to productivity

GM salmon, herbicide-resistant soybean and insect-resistant cotton increase productivity through different expressed traits: growth control, survival during weed control and protection from insect feeding.

GMO Engineered trait and mechanism Productivity benefit Management boundary
GM salmon growth-hormone expression is maintained for more of the year, so fish grow more rapidly reach market size sooner, increasing production rate prevent escape and assess welfare, competition and gene-flow risks
Herbicide-resistant soybean crop survives application of the relevant herbicide while susceptible weeds die less competition for light, water and mineral ions, so yield can rise and weed control may need less labour repeated use selects resistant weeds; gene flow and herbicide use/residues require management
Insect-resistant cotton a transferred bacterial gene produces a protein toxic to target insect larvae less feeding damage, higher usable yield and potentially less insecticide spraying target insects can evolve resistance; refuges/monitoring and non-target effects matter

Do not swap the mechanisms. The soybean is resistant to a herbicide; it does not make the herbicide. The cotton plant produces an insecticidal protein against target pests. The salmon modification changes the timing/level of growth-related expression rather than protecting a crop from weeds or insects.

Each trait can improve productivity only under suitable production conditions. Faster growth, easier weed control or reduced insect loss must be weighed against resistance evolution, containment, ecological effects and management cost.

GM food decisions depend on trait, evidence and stakeholders

Ethical and social evaluation of a GMO must name the organism, engineered trait, farming context and affected groups. A benefit to food supply may coexist with ecological, health, ownership, welfare or consumer-choice concerns.

Potential benefit Linked concern or condition Stakeholders
higher yield or less crop loss may increase supply and reduce food prices benefit depends on climate, soil, management and fair distribution farmers, consumers, governments
less insecticide spraying can reduce cost, worker exposure and environmental contamination pests may evolve resistance and non-target species must be monitored farm workers, neighbouring communities, ecosystems
herbicide-resistant crops simplify weed control and may reduce tillage herbicide use/residues, resistant weeds and gene flow to non-GM crops can create costs GM and non-GM farmers, consumers
rapid animal growth can increase production containment, animal welfare and effects of escaped organisms require evidence producers, consumers, animals, wild populations
patented seed can fund innovation and provide a useful trait price, seed saving, dependency and unequal access can disadvantage some farmers companies, farmers, regulators

Food safety testing, environmental risk assessment, post-release monitoring, resistance management and clear labelling can reduce uncertainty and protect consumer choice. Cultural or religious values may still lead people to different decisions even when they accept the same biological evidence.

Do not argue that all GMOs are safe, unsafe, ethical or unethical. Reach a conditional judgement: state the specific benefit, identify who bears each risk or cost, judge the quality of evidence, and explain which regulation or management would change the balance.