Mendel in the Kitchen A Scientist's View of Genetically Modified Foods (2004) / Chapter Skim
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3 The Power in the Earth
3 The Power in the Earth
Pages 47-66
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From page 47... ...
In 1798 the English economist and cleric Thomas Malthus laid out what he called the immutable laws of human existence: "First, That food is necessary to the existence of man. Secondly, That the passion between the sexes is necessary and will remain nearly in its present state." Passion, in Malthus's time, led inexorably to children (he had no inkling of birth control)
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From page 48... ...
A Malthusian worldview remains synonymous with the gloomy belief that only famine, disease, and war can control population and solve the world's food problems. But birth control was not the only concept Malthus's essay did not take into account.
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From page 49... ...
James Murray, an Irish doctor with a calling toward chemistry, found that acid converts calcium phosphate into calcium hydrogen phosphate and calcium dihydrogen phosphate, both of which dissolve readily. Murray mixed a paste of acid-treated bones or rocks with sawdust and bark to produce a slow-release fertilizer.
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From page 50... ...
An experiment in Paris, by chemist Jean-Baptiste Boussingault, had shown that plant nitrogen came from soil nitrates and ammonia, suggesting that nitrogen fertilizer was a good idea. Boussingault's data, however, were found to be faulty, and rival work by another French scientist, GeorgesVille, claiming that plants took nitrogen directly from the air, was taken up and popularized by the great Liebig.
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From page 51... ...
Yet sometimes a potato plant sets fertile seed. Discovering one of these rare seedpods at the edge of his garden, Burbank grew the 23 seedlings and selected 2.
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From page 52... ...
He grew hundreds of stock trees, each holding dozens of grafts. The technique of grafting had been known since ancient times.Yet in early America, grafting -- just like molecular techniques today -- was condemned as unnatural, as interfering with God's plan.
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From page 53... ...
Orchardists, writes Sue Hubbell in Shrinking the Cat: Genetic Engineering Before We Knew About Genes, plant "proven grafted stock and never, never, never save apple seeds to plant unless they have a speculative, adventuresome, experimental set of mind." Because of the "perversely complicated" genetics of the apple, every tree that grows from a seed is a new variety -- and most of them are commercial failures. Fortunately for fruit lovers, the divine essence of the orange tree was not a consideration when the seedless navel orange was discovered as a sport or bud variation on a seedy variety in eastern Brazil in the early 1800s.
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From page 54... ...
Having found a yellowish berry (grown under the hyperbolic name Crystal White) , Burbank decided to cross it with a black variety to see if, paradoxically, that would whiten the fruit.
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From page 55... ...
Yields, however, remained static between 1860 and 1900."The new varieties that flowed in an ever greater stream from public researchers were not raising average yields, but were permitting extension of production into new areas," noted rural sociologist Jack Kloppenberg in his book First the Seed: The Political Economy of Plant Biotechnology, 1492-2000. "Advances in plant breeding served to maintain levels of yield that might otherwise have declined." It was the scholarly insights of Gregor Mendel, not the brute-force approach of Luther Burbank, that increased crop yields without bringing more land under cultivation.
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From page 56... ...
"An exact determination of the laws of heredity," Bateson said, "will probably work more change in man's outlook on the world, and in his power over nature, than any other advance in natural knowledge that can be foreseen." Bateson's statement was remarkably prescient: Mendel's laws did lead, if indirectly, to contemporary molecular techniques for plant improvement. One of the few plant breeders not excited by Mendelism was Luther Burbank, who learned about it just after releasing another of his triumphs, the Shasta daisy.
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From page 57... ...
He stood "between the small-scale farmer-breeders who through most of history slowly but steadily built up mankind's stock of useful plants, and the modern scientific hybridizer," writes his biographer. In place of theory he had "a special gift of judgment," according to De Vries, who had made a point of going to see Luther Burbank's gardens.
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From page 58... ...
To cross two corn varieties, Shull plucked off the tassels of one variety, letting the other provide the pollen to fertilize the female flowers; he was thus assured that any ears resulted from a cross between the two. The Kansas corn had full, round kernels because those kernels held more starch: being a long and bulky polymer, the starch filled the space inside the kernel completely.
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From page 59... ...
A year later he explained how his observations could be put to practical use in a short paper called, "A pure-line method of corn breeding." He admitted that this method of producing seed corn was probably more expensive, and he was unsure if the increase in yield would be enough to cover the cost."These are practical questions which lie wholly outside my own field of experimentation," he concluded, "but I am hoping that the Agricultural Experiment Stations in the corn-belt will undertake some experiments." The Agricultural Experiment Stations were not thrilled. Shull's method was "impractical,""too complex," and "not cost-competitive,"
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From page 60... ...
Moreover, the technique, wrote one USDA breeder, echoing Johnny Appleseed and in turn to be echoed by Prince Charles and Congressman Kucinich, did"violence to the nature of the plant."It was"dangerous." Those experiment stations that did try the technique, writes Charles Heiser in Seed to Civilization, thought the inbreds were "such sick-looking plants"that they grew them only"in out-of-the-way places where farmers would be unlikely to see them." Otherwise,"they would think the breeders were working in the wrong direction." Yield, in fact, was not the standard by which corn was judged in the early 1900s; beauty was. At the corn shows popular throughout the country, a farmer would enter a single perfect ear, hoping to win an expensive tool or machine.
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From page 61... ...
Plant breeder Don Duvick, who recently retired from Wallace's Pioneer Hi-Bred company as Vice President for Research, recalls from his childhood: We planted our first hybrid corn in 1936, a year of disastrous drought throughout the Corn Belt, including our section of northeastern Illinois. It was on only a small part of our corn acres; most of them were planted to our "tried and true" open pollinated variety.
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From page 62... ...
Though he was most likely not in the audience when Luther Burbank lectured in 1925 at the First Congregational Church in San Francisco, Henry Wallace might have agreed when Burbank proclaimed,"What a joy life is when you have made a close working partnership with Nature, helping her to produce for the benefit of mankind new forms, colors, and perfumes in flowers which were never known before; fruits in form, size, color, and flavor never before seen on this globe; and grains of enormously increased productiveness, whose fat kernels are filled with more and better nourishment, a veritable storehouse of perfect food -- new food for all the world's untold millions for all time to come." The year Wallace founded his Pioneer Hi-Bred Corn Company, the world population was 2 billion. By 1950, when the first mutationbred crops formed by irradiating seeds were being sown, and F
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From page 63... ...
In 1944 he became director of the wheat program, "a job for which there was little competition, backwater Mexico in the 1940s not being an eagerly sought-after posting," notes one writer. In his 1970 Nobel Peace Prize lecture, Borlaug recalled, "At that time, Mexico was importing more than 50 percent of the wheat that it consumed, as well as a considerable percentage of its maize.Wheat yields were low and static, with a national average yield of 750 kilos per hectare, even though most of the wheat was grown on irrigated land." The soils were "impoverished," and chemical fertilizer "virtually unknown." Research at the Mexican institute "from the outset," said Borlaug, "was production-oriented and restricted to that which was relevant to increasing wheat production.
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From page 64... ...
As Borlaug explained in his Nobel lecture, "Through a series of crosses and re-crosses begun in 1954, dwarfness was incorporated into the superior, new-combination Mexican types, finally giving rise to a group of so-called dwarf Mexican wheat varieties." By changing the plant's architecture to emphasize a short, sturdy stalk, the dwarfness trait allowed the wheat to produce heavier seed heads -- given enough water and nitrogen -- without falling over in a breeze. In addition, the plants were not affected by length of day (and so could grow at a range of latitudes)
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From page 65... ...
A year later Indian scientist Gurdev Singh Khush joined the IRRI staff. Khush had a hand in breeding more than 300 rice varieties, including IR36, which, according to IRRI, was "the most
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From page 66... ...
66 MENDEL IN THE KITCHEN widely planted variety of rice, or of any other food crop, the world has ever known." With the new varieties, rice yields more than doubled from the mid-1960s to 1990 throughout Asia. Upon Khush's retirement in 2001 the IRRI annual report claimed that "in any rice field, anywhere in the world, there's a 60 percent chance that the rice was either bred at IRRI under his leadership or developed from IRRI varieties." Said Norman Borlaug, "The impact of Dr.
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