On this page
If you are revising Chapter 10 of NCERT Class 12 Biology, “Biotechnology and its Applications”, one short list is worth learning by heart for CBSE boards and NEET-UG: the advantages of genetically modified crops. Here is that list in the textbook’s own order, what each point means, what the research says, and a plan for writing it as a 5-mark answer.
What are the advantages of GM crops according to NCERT?
NCERT defines Genetically Modified Organisms (GMOs) as plants, bacteria, fungi and animals whose genes have been altered by manipulation (NCERT Class 12 Biology, Chapter 10). On the same page, it says genetic modification has:
made crops more tolerant to abiotic stresses (cold, drought, salt, heat);
reduced reliance on chemical pesticides (pest-resistant crops);
helped to reduce post-harvest losses;
increased the efficiency of mineral usage by plants, which prevents early exhaustion of soil fertility;
enhanced the nutritional value of food, for example Golden Rice, a Vitamin A-enriched rice.
The chapter adds a use that students often forget: GM has also been used to create tailor-made plants that supply industries with starches, fuels and pharmaceuticals.
“Abiotic” means non-living: weather and soil, not pests. Pest resistance is a separate point. Mixing the two up is a common slip in short answers.
Do GM crops really reduce pesticide use?
The textbook’s main example is Bt cotton. A Bt toxin gene, cloned from the bacterium *Bacillus thuringiensis*, is expressed in the plant so it resists insects without insecticide sprays. NCERT says this “in effect created a bio-pesticide” (NCERT, Chapter 10). If you need the gene names, read which Cry genes control cotton bollworms and corn borers.
On average, the research backs the textbook’s claim. Wilhelm Klümper and Matin Qaim combined 147 studies and found that adopting GM crops reduced chemical pesticide use by 37%, raised crop yields by 22% and raised farmer profits by 68% (PLOS ONE, 2014). They also found bigger yield and pesticide gains for insect-resistant crops than for herbicide-tolerant ones, and bigger yield and profit gains in developing countries.
Why do post-harvest losses and mineral use matter?
Food lost between the farm and the shop was grown but never eaten. FAO estimates that 13.3% of food was lost globally after harvest in 2023, across the farm, transport, storage, wholesale and processing stages (FAO, SDG indicator 12.3.1). A crop that survives storage and transport better cuts into that loss. NCERT states this advantage without naming an example, so one clear sentence of explanation is enough in an exam.
Mineral-use efficiency is about the soil. A plant that makes better use of the nutrients it absorbs takes less out of the field for the same growth. NCERT ties this to preventing early exhaustion of soil fertility. Write that reason in your answer, because it shows you understand the point and haven’t just memorised it.
How does Golden Rice improve nutrition?
Golden Rice is engineered to make beta-carotene, a pro-vitamin A, in the grain. For “Golden Rice 2”, scientists used a phytoene synthase gene from maize. Total carotenoids rose up to 23-fold, to a maximum of 37 micrograms per gram, compared with the original Golden Rice (Paine et al., Nature Biotechnology, 2005).
Are there limits to these advantages?
Yes, and a strong answer to a “discuss” question shows it. In India, pink bollworm has evolved resistance to Bt cotton. A study covering 38 districts in 10 major cotton-growing states found that in central and southern India, the annual average recovery of pink bollworm larvae from two-toxin Bt cotton was 28.85–72.49% during 2014–2017 (Naik et al., Pest Management Science, 2018). GM crops also need approval before farmers can grow them. Read what the GEAC does to see who decides this in India.
How do you write a 5-mark answer on GM crop advantages?
Use this five-step plan, and give each line a keyword and a reason:
Define a GMO in NCERT’s words (organisms whose genes have been altered by manipulation).
Name the five advantages in textbook order, each with its bracket: abiotic stress (cold, drought, salt, heat), pesticides (pest-resistant crops), post-harvest losses, mineral use (prevents early exhaustion of soil fertility), nutrition (Golden Rice, Vitamin A).
Give one example for pesticides (Bt cotton, a bio-pesticide made by the plant itself).
Add the industrial use (starches, fuels, pharmaceuticals).
If the question says “discuss” or “evaluate”, add one limitation, such as pink bollworm resistance.
A common trap is to call a GM crop a hybrid. Hybrids come from crossing; transgenic plants carry a gene moved in from another organism. Our guide to transgenic vs hybrid plants sets out the difference.
If a term like protoxin, carotenoid or abiotic stress is still unclear, look it up in the Fermi Concept Library. It covers every concept in biology, and each one has its own lesson and its place in the map. Then close the book and write the five points from memory.
