Thursday, June 30, 2011

Crop Diversity

The other day, my super cool friend and future Explorer, Kate and I had a conversation about linguistic diversity and some of the issues related to and benefits of preserving that diversity. Similar to the recent and rapid decline of linguistic diversity, plant diversity (of both domesticated and wild species) is also being threatened.

The July issue of the National Geographic Magazine had an interesting article about the dwindling diversity of many domesticated crop and animal species and efforts being taken to preserve and protect that diversity. Declining diversity among many commonly eaten foods is pictured in the diagram below.
Source: http://ngm.nationalgeographic.com/2011/07/food-ark/food-variety-graphic   

Read part of the article after the break



Published: July 2011
By Charles Siebert

It took more than 10,000 years of domestication for humans to create the vast biodiversity in our food supply that we're now watching ebb away. Selectively breeding a wild plant or animal species for certain desirable traits began as a fitful process of trial and error motivated by that age-old imperative: hunger. Wild wheat, for example, drops its ripened kernels to the ground, or shatters, so that the plant can reseed itself. Early farmers selected out wheat that, due to a random genetic mutation, didn't shatter and was thus ideal for harvesting.

Farmers and breeders painstakingly developed livestock breeds and food crops well suited to the peculiarities of their local climate and environment. Each domesticated seed or breed was an answer to some very specific problem—such as drought or disease—in a very specific place. The North American Gulf Coast Native sheep, for example, thrives in high heat and humidity and has broad parasite resistance. On the remote Orkney Islands, North Ronaldsay sheep can live on nothing but seaweed. Zebu cattle are more resistant to ticks than other cattle. In Ethiopia a small, humpless, short-horned cattle breed called the Sheko is a good milk producer that withstands harsh conditions and has resistance to sleeping sickness.

Such adaptive traits are invaluable not only to local farmers but also to commercial breeders elsewhere in the world. Finnsheep, for example, long raised only by a small group of Finnish peasants, have become vital to the sheep industry because of their ability to produce large litters. The Fayoumi chicken, an indigenous Egyptian species dating back to the reign of the pharaohs, is in great demand as a prodigious egg layer with high heat tolerance and resistance to numerous diseases. Similarly, the rare Taihu pig of China is coveted by the world's pig breeders for its ability to thrive on cheap forage foods and its unusual fertility, regularly producing litters of 16 piglets as opposed to an average of 10 for Western breeds.

The irony is that the dangerous dwindling of diversity in our food supply is the unanticipated result of an agricultural triumph. The story is well-known. A 30-year-old plant pathologist named Norman Borlaug traveled to Mexico in 1944 to help fight a stem rust epidemic that had caused widespread famine. Crossing different wheat varieties from all over the world, he arrived at a rust-resistant, high-yield hybrid that helped India and Pakistan nearly double their wheat production—and saved a billion people from starvation. This so-called green revolution helped introduce modern industrialized agriculture to the developing world.
But the green revolution was a mixed blessing. Over time farmers came to rely heavily on broadly adapted, high-yield crops to the exclusion of varieties adapted to local conditions. Monocropping vast fields with the same genetically uniform seeds helps boost yield and meet immediate hunger needs. Yet high-yield varieties are also genetically weaker crops that require expensive chemical fertilizers and toxic pesticides. The same holds true for high-yield livestock breeds, which often require expensive feed and medicinal care to survive in foreign climates. The drive to increase production is pushing out local varieties, diluting livestock's genetic diversity in the process. As a result, the world's food supply has become largely dependent on a shrinking list of breeds designed for maximum yield: the Rhode Island Red chicken, the Large White pig, the Holstein cow. In short, in our focus on increasing the amount of food we produce today, we have accidentally put ourselves at risk for food shortages in the future.

To read the entire article click here



1 comment:

  1. Wow, it's amazing to see how intertwined two distinct fields, like agriculture and linguistics, really are. I am also very jealous to see that once upon a time I could have had my pick of 408 different kinds of tomatoes. Do you know what is being done, if anything, to preserve crop diversity?

    ReplyDelete