Airdate: Mar 14, 2019
Scientist: Bill McKently
The Human Side of Natural Selection
Long before biotechnology, farmers have sought ways to bring predictability to their ever-changing crops.
The Human Side of Natural Selectionambience: Dawn Chorus Long before the advent of biotechnology, farmers have sought out ways to bring predictability to their ever-changing crops. For apple farmers, grafting has been a way of ensuring that the same varieties of apples land on our grocer's shelves year after year. I'm Jim Metzner, and this is the Pulse of the Planet.Bill McKently is the owner of Saint Lawrence Nurseries in New York. This time of year, he's grafting apple trees - slicing a branch off one apple tree and carefully joining it to the detached root of another tree. Now, in the spring, McKently plants this root stock with the branch grafted to it, and in time it will grow into a tree whose apples are identical to those that came from the tree he cut the branch from.McKently: If you plant seeds, you don't get what you started with. Good example is a man and wife have kids and their kids are not identical to either the man or the wife. It doesn't work that way. It's called sexual reproduction. It's the same thing we have in the plant world.In sexual reproduction, an offspring inherits a variation of the characteristics of both parents. The results are varied and this variation helps nature to select the hardiest characteristics of a species over time - remember survival of the fittest? But the kinds of apples that nature might select for won't necessarily be the apples that people want to eat.McKently: The advantages of grafting have to do with production and reliability and all kinds of things that humans want. People want to know that if they have a tree that is said to be a Macintosh tree, they know what those traits are. They've eaten macintosh all their life, and they want that. They don't want something else.For hundreds of years, farmers have chosen the best quality apples to use for grafting, giving the process of natural selection a decidedly human flavor. This archival program is part of our thirtieth anniversary celebration. If you want hear more, check out our podcast. Im Jim Metzner and this is the Pulse of the Planet.