Guide three
Plant Biotech
Farmers have been changing crops for about ten thousand years by saving seed from the best plants. Plant biotechnology adds laboratory tools to that long story.
Selection and breeding
Conventional breeding crosses two parent plants and selects the offspring with useful traits, such as bigger grain, earlier ripening or resistance to a disease. It works well but can take many seasons. Maize, cassava, groundnuts and beans grown today all come from generations of this patient work.
Tissue culture
A small piece of plant tissue, placed in a sterile jar with a jelly of nutrients and plant hormones, can grow into many new plantlets. Because each one is a copy of the parent, tissue culture is used to multiply healthy, disease-free planting material of crops such as banana, cassava, sweet potato and many ornamental plants.
Marker-assisted breeding
Scientists can read short stretches of a plant’s DNA that sit close to a useful gene. By checking seedlings for these markers, breeders can keep the promising plants and set others aside long before they flower, saving time and field space.
Genetic modification and gene editing
| Approach | In short |
|---|---|
| Genetic modification (GM) | A gene, sometimes from another species, is added to a plant’s DNA to give a new trait such as insect resistance. |
| Gene editing | Tools such as CRISPR make small, targeted changes to a plant’s own DNA, often similar to changes that could occur naturally. |
How these crops are tested, approved and labelled differs a great deal from country to country. Some countries treat certain gene-edited plants like conventionally bred ones; others regulate them in the same way as GM crops. This page describes the techniques and does not take a side in those debates.
Small helpers in the soil
Biotechnology is not only about the plant. Bacteria that live in root nodules of beans, groundnuts and other legumes take nitrogen from the air and make it available to the plant. Farmers in many regions coat legume seed with these bacteria, called inoculants, to help the crop.
For decisions about seed, crop protection or what you may legally grow, rely on your national agricultural extension service and regulators.