How to grow a cocoa tree quickly
Growing a cocoa tree – the plant whose pods turn into chocolate – takes patience. It takes three to five years for a cocoa bean to develop into a fruit tree. Each tree produces a limited number of seeds. And these seeds are not the same as the mother plant. The genes inside the seeds are a mixture. Some come from the plant that grows the fruit. Others come from the tree that provided the pollen. This is a challenge for researchers studying the genetics of cocoa plants. As they try to improve the characteristics of these trees from generation to generation, they don’t want to wait years to find out if a tree has good genes for specific traits.
And now they don’t have to. Mark Guiltinan and Siela Maximova are plant biologists at Pennsylvania State University in University Park. Their secret: cloning.
They start with a tree that has the genes that interest them. These genes could help the tree resist disease, for example. Or the genes could help the tree grow faster or make better tasting chocolate. (Researchers do not insert genes into the tree – it is not genetically modified. Rather, they look for genes that developed in them naturally.)
Scientists cut tiny pieces of flowers from a tree. They put the pieces in a germ-free solution. Then they add hormones which cause each piece of flower to start developing into a young plant, as if it were a seed.
This way, researchers can create thousands of plants from the pieces of a single flower. These new plants are clone. This means that they have the exact same genes as their parent tree – and each other.
Identical genes are a blessing and a curse. These genes can make a cocoa tree grow many pods or prevent it from contracting a certain disease. But there are many different diseases of cocoa. Resistance to one disease may not protect the plant against another. Because all of these young plants share the same genes, they are all vulnerable to the same pests and diseases. If someone were to plant a farm or an entire plantation with identical cocoa trees, a single infection could later wipe them all out.
Guiltinan and Maximova are very aware of the problem. “We would never recommend just one variety,” says Guiltinan. Instead, he suggests that cocoa farmers are planting many different types of genetically different trees. Each variety is said to produce many pods and be resistant to at least one disease. This should help ensure a healthy field and a harvest of delicious cocoa.