How Evolutionary Plant Breeding Is Essential for Genetic Biodiversity and Surviving Climate Change
= "We need crops that can adapt, and that means what we call 'evolutionary plant breeding' rather than the usual 'selective plant breeding'. We have to breed the crops we rely on for a period of instability, and that means genetic diversity".
Discussion
Oliver Tickell:
"To feed the world we must abandon not just GMOs but all diversity-destroying selective crop breeding, organic farmer John Letts told Oliver Tickell. Only by using biodiverse local seed mixtures that evolve in the field can food production adapt to climate change without ever-increasing chemical inputs, and meet human needs for wholesome nourishment.
We need crops that can adapt, and that means what we call 'evolutionary plant breeding' rather than the usual 'selective plant breeding'. We have to breed the crops we rely on for a period of instability, and that means genetic diversity.
"Just focusing on GMOs (genetically modified crops) is not enough. The point is, what is happening in the fields even without GMOs?
"Industrial agriculture only works with tons of soluble nitrogen, fungicide, insecticide and herbicide. And the result is that the bees are dying out.
"We cannot go on like this. GMOs are just the final tweak in the entire system of industrial agriculture that is destroying our environment and ruining our health. So we have to do more than just complain about it. We have to set out the alternative."
"The first thing you notice about John's wheat fields is the tangle of weeds that covers the ground to a height of two to three feet. Then, rising above, the extravagant height of the wheat, seed heads hanging four or five feet above the ground - allowing the grain to be (more or less) cleanly harvested, leaving weeds and high stubble to be ploughed back into the soil and raise its organic content.
Back in the barn, John reaches into a sack of wheat. "There's a thousand times more genetic diversity in this one handful of grain than in an entire 100-acre field on a conventional farm", he says. Composed of 150 varieties from seed banks and farmers across northern Europe, it's nothing short of a genetic treasure, secured by being grown.
"The only really safe place for seeds is growing in the field. I have had grain from seed banks that has never germinated. Seeds are only safe in the hands of farmers and when they are planted."
But what exactly is so important about all this genetic diversity? First we have to understand the extraordinary "genetic cleansing" that has taken place since the early 20th century. For millennia, cereals were grown as 'landraces', incorporating three levels of diversity. Every field would include maybe half a dozen separate cereal species, divisible into as many as 200 varieties. Each would, in turn, embody considerable genetic diversity. During the 19th century, farmers in search of higher yields began to pick out specific lines that yielded higher returns under ideal agronomic conditions. Then, in search of greater stability and uniformity, crop breeders selected single seeds from these lines, bulked them up over successive plantings, then named and marketed them as distinct varieties.
The next step, which began shortly before the first world war, was to hybridise these named varieties in search of the ideal combination of agronomic qualities, putting together, for example, traits for large seed heads and short straw to increase yields yet further - again, under ideal conditions - and increase profitability for 'efficient' farmers.
"What the plant breeders have achieved is to wipe out 99.99% of the original genetic diversity in the field", says John. "Production has shot up, but so have inputs. The crops respond well to nitrogen, but they are shallow-rooted and can't reach down into the subsoil for water and nutrients.
"Because they are genetically uniform they can no longer evolve in the field to withstand insects and fungi and have to be constantly sprayed with pesticides. The short straw length means that more of the plants' energy goes into the grain - but then they can't grow up above the weeds, so the system relies on repeated use of herbicides.
"And a huge concern now is climate change. We need genetically diverse crops that can evolve to meet changing conditions, producing reliable yields all the time, rather than maximum yield when everything is just right but with the risk of total crop failure when you get flood, or drought, or some new insect or fungus or virus.
"We need crops that can adapt, and that means what we call 'evolutionary plant breeding' rather than the usual 'selective plant breeding'. We have to breed the crops we rely on for a period of instability, and that means genetic diversity." (http://www.theecologist.org/magazine/features/2988317/farming_with_the_grain_john_letts_and_his_evolutionary_made_for_organic_heritage_seeds.html)