Plate-Wise •  5/10/2021

What’s the difference between plant breeding and genetic engineering?

Written By Holly Loucas 
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Assortment of large, small and differently colored tomatoes

With summer approaching in the Northern Hemisphere, many home gardeners are starting to comb through seed catalogues and gardening stores to select tomato varieties for the year. There are hundreds of choices, as tomatoes have been bred in all shapes, sizes and flavors. It’s this profusion of produce that leads to a question I’m asked a lot: What’s the difference between plant breeding and genetic engineering?  

Let’s start with plant domestication

While we don’t have a date when the first crop was bred, what we do have are records of the domestication of food plants by early farmers. Farmers saved the best, most desirable seeds from the food they produced to plant the following year. This process is called domestication and has gone on for hundreds and thousands of years. The result of domestication are seeds with characteristics that are desirable for producing the plants in a specific region. This could be drought tolerance for a region that was dry, disease resistance in other areas, as well as taste and abundance.

What does plant breeding mean?

While domestication simply saved the best seeds to plant in the following year’s crop, breeding started to take things one step further. Through breeding, plants are crossed with other plants to create new seeds for the next crop. Plants with desirable characteristics are used as females, and pollen is selected from a specific plant with different desirable characteristics. Pollination is done by hand to minimize cross-pollination with unwanted pollen. For example, a high-yielding plant can be used as a female with pollen from a disease-resistant plant, so the resulting seed would be high-yielding AND disease-resistant.

If only it were that easy! In reality, it takes years to breed a crop — such as broccoli or carrots — with a characteristic of interest. But in some cases, breeding is actually impossible. Basic plant breeding is often limited by species constraints. Some flowers are simply not compatible with pollen from other flowers outside of their species.

Plant breeders over the years have developed ways around these barriers. Techniques such as mutagenesis and polyploidy have been employed to increase the genetic diversity of plants

  • Mutagenesis uses radiation to find beneficial traits in seeds. This technology was used to create the ruby red grapefruit
  • Polypoloidy increases the amount of genetic material in a plant. It helps increase fruit size or fertility of a plant. This technology was used to create seedless watermelon.

The most common forms of mutagenesis are chemical or radiation — both of which induce thousands of unknown random mutations in the hopes of finding beneficial characteristics to make a better crop. More than 3,000 plants have been produced this way, most of which can be found in the produce section of your grocery store!

Genetic engineering, a more precise way to breed

When it comes to genetically engineered (GE) plants, the difference is that genetically engineered plants are produced in a lab by targeting specific genes of interest and inserting only that gene into the resulting GE plant. Rather than relying on random mutagenesis or cross-hybridizing of whole chromosomes, GE plants can be extremely specific and should be considered safer than their predecessors. Because the process is more precise, scientists can know exactly what they are manipulating and examine unintended consequences before products leave the laboratory. 

That’s why it’s often hard to understand why these techniques – which have been used by farmers and scientists for years – are considered harmful while plants that are bred through other means are labeled organic and conventional. At the root of it, these two processes are similar and create plants that are healthy, safe and abundant.

Check out more from Plate-Wise!

Want to learn more about GMOs? Read up on our library of GMO posts here, or read more about selective gene engineering here.