Genetically Modified Crops

Differences between conventional plant breeding and GM



	Tomatoes from a Greek garden. Are both of these "natural"? (Photo: Chrissi Nerantzi)

Natural vs unnatural?

Some opponents of GM crops claim that GM is bad idea because it's “unnatural”. However the distinction between natural and unnatural has been very unclear for a long time.

Humans have been saving seeds from useful varieties of plants and growing them for over 12,000 years.
Over the millennia, crop plants have changed enormously from the original wild species.

What do you understand by the word "natural"? When you look at the British countryside, is it "natural"? Why?

Traditional plant breeding

Through cross breeding existing varieties, the breeder aims to re-shuffle the plants' genetic material to produce new varieties that may have useful characteristics.
Approx 40% of the genetic material is reorganised in the resulting hybrid plant.
From these new plants, the breeder uses a slow process of selection to work out which are useful and which are not.
It is a very imprecise technique - thousands of crosses are created to find one or two useful varieties.

Non GM genetic techniques. In the 20^th century, new methods of producing genetic variety emerged long before GM technologies were developed. For example, plant breeders often introduce new genetic variation in a crop species by exposing the seeds to gamma radiation or chemicals that cause genetic mutation. Much of the UK’s beer is produced using a mutant variety of barley called Golden Promise that was generated by radiation.

GM technology by contrast, only alters one or two specific genes at a time, which supporters claim leads to far more predictable outcomes than traditional breeding.

The species barrier