Why Do We Eat So Many Cloned Plants?
In 1868, Maria Ann Smith spotted an interesting apple seedling growing by a creek on her property. As the plant aged, it produced apples with green skin and tart flesh. Maria Ann Smith’s apple has been propagated thousands of times over the last 150 years. You know apples as the Granny Smith.
Every Granny Smith apple is a clone of Maria Ann Smith’s 1868 creekside apple tree. Every Granny Smith apple you have ever eaten is an exact copy of that original plant. How is this possible? Did Granny Smith have a futuristic cloning machine in her nineteenth-century root seller? No, but she did have access to a propagation technique that’s thousands of years old – grafting.
What is Grafting?
Grafting involves removing a plant bud or segment (scion) from one plant and attaching it to a separate compatible plant (the rootstock). Once healed, new growth from the graft will have the same qualities (fruit, etc.) as the plant from which it was taken.
Grafting can be used to clone a tree, create a tree with multiple varieties, or convert a tree from one variety to another. Almost all of the fruit you eat comes from a grafted tree.
Cloned Fruit vs Seeds
Why are we using grafting to clone fruit when we can plant some seeds? Can’t you plant a Granny Smith apple seed to get another Granny Smith tree? Unfortunately, you can’t. Ironically, because apples are genetically diverse, their seedlings are usually nothing like their parents. Ironically, when it comes to apples, the apple falls very far from the tree.
When a seedling is similar to its parents, we say it is “true to type” or “comes true” to seed. Some fruits, like apricots, come fairly true to seed. Apples are not true to seed. So the only way to duplicate a delicious apple variety is to clone it. The advantage of cloning is that you know exactly what you’re getting – growth habit, disease tolerance, fruit – it will all be the same as the original plant. It’s why every navel orange you’ve ever eaten tastes the same – clones from one original tree.
Seeds, in contrast, are genetic recombinations of their parents and don’t necessarily look or take the same. Seeds aren’t a reliable way to grow a copy of a parent plant, but they’re the only way to grow and discover new varieties – like the selling Granny Smith found at the creek.
Growing Seedless Fruit Varieties
The Cavendish banana is an extreme example of cloned fruit – a single seedless plant grown in a British greenhouse that has completely dominated the global banana industry. Unless you’ve gone out of your way to find the excepts, there’s a good chance that every banana you’ve ever eaten is a Cavendish – which is a bummer.
As bananas grafted? Bananas are large herbaceous plants; the easiest way to propagate them is to replace a chunk of the root.
A downside of cloning is that it creates a loss of diversity, which makes plants susceptible to climate change, insects, and diseases. In the case of the Cavendish banana, a blight called Panama Disease is working its way through banana plantations.
Cloned Fruit As Culture
To keep a cloned fruit variety alive requires continuously cloning it every generation. With a life expectancy of around eighty years, Granny Smith’s original seedling is likely long gone, but cones from that original tree exist by the thousands. The Granny Smith apple variety can be maintained indefinitely as long as there’s demand and people to grow.
It’s impossible to know for sure, but the oldest reported cloned fruit variety is the Annurca Apple which is still available and was written about by Pliny the Elder as early as the year 79. If true, the Annurca apple represents almost two-thousand years of unbroken propagation. If a single generation of apple farmers failed to graft Annurca, the variety would have been lost forever.
Cultivated varieties of fruit represent hundreds or thousands of years of meticulous selection, continuous propagation, and patience. They are the collective wisdom of culture and place.
Cloning is keeping thousands of culturally important plant varieties alive. Globally, over seven thousand apple varieties represent almost every place on the planet. Some of these varieties may only exist as single plants in someone’s backyard or are culturally significant to a region or community. And yet, most of us are only familiar with a few varieties – red and golden delicious, spartan, gala, fuji, granny smith, etc., often selected for appearance and shelf life rather than flavour. Unfortunately, supermarket varieties have gradually replaced more enjoyable and interesting local cultivars over the years.
Cloned Fruit – Use It Or Lose It
Here are four ways to protect cultivated varieties of plants:
- Support small fruit and vegetable producers who are cultivating interesting cultivars and heirlooms.
- Plant local or endangered cultivars. Look for small-scale nurseries selling interesting and lesser-known cultivars. Look online, as many nurseries will ship plants to your front door. To find local and endangered varieties of food, visit Slow Food’s Ark of Taste project.
- Find a gardening or fruit growers group. Ask people what they’re growing, what’s working, and where they’re finding their plants. Locally, I like the Hardy Fruit and Nut Trees of Alberta.
- Keep an eye out for interesting plants. New varieties are waiting to be discovered – an apricot seedling in a boulevard, wild goji in the river valley (both Edmonton examples), or a seedling growing down at the creek. You may discover the next great variety.