By Elena Day
These days more people are opting for a wheat-less or “gluten-free” lifestyle. If wheat rust persists, many more of us will be “gluten-free.”
I first read about wheat rust about two years ago. It is often called the “polio of agriculture.” It was virtually absent from agriculture for 50 years and now, since 1999, it has spread 5,000 miles from Uganda to the Indian state of Punjab. It is a fungal disease spread by windborne spores that interferes with photosynthesis and hinders the wheat’s ability to produce grain. It gains a foothold in wetter weather, which is also beneficial to the culture of wheat. Rust has been forever present in wheat cultivation. The Romans sacrificed dogs to ward it off. In the first half of the 20th century wheat rust killed off a fifth of North America’s wheat harvests in periodic epidemics.
The Green Revolution that followed WWII saw the end of wheat rust (more specifically, stem rust) due to the research of Norman Borlaug, who successfully isolated a resistant gene. The new crossbred plants resisted rust and also produced higher crop yields. Farmers were thrilled at the increased yields, abandoning their locally adapted wheat seeds for Borlaug’s Sr31 wheat.
The “Green Revolution” may be proving itself quite a bit less “green” in the long run. It may have increased crop yields and staved off starvation for many after World War II, but today malnutrition persists among the world’s poor. Genetic diversity has been lost as fewer varieties of food crops are cultivated. Seeds today are even patented, thereby discouraging seed saving. At one time there were 25,000 types of wheat adapted to a wide range of temperate climates. Since the late 1940s, smaller agriculturist and subsistence farmers have been forced from their land as larger and larger enterprises produce our food and food distribution systems are consolidated. The increased and widespread use of chemical fertilizers, pesticides and herbicides is the basis of the initial success of the Green Revolution in the second half of the last century. Meanwhile the Green Revolution has foisted onto humans a host of new and difficult problems.
Wheat was first domesticated from wild grasses around 9,000 B.C. in southeastern Turkey or present- day Iraq. By 2000 B.C. wheat cultivation had spread to Europe, Asia and North Africa. Two traits differentiated domesticated wheat from wild grasses. The first was shatter-proof spikes at maturity. Shattering is a good thing for seed dispersal in a natural population. Shattering is a negative trait for a farmer who must retain the seed as his crop. The second qualifying trait in domestication is a change from hulled forms to naked forms so that the wheat can be threshed. (Threshing is beating or flailing the grain in order to separate the wheat kernels from the wheat straw.)
Seventy percent of the Earth’s agricultural land is planted in wheat. Wheat provides energy, protein and many vitamins and minerals. One website I visited claimed that one acre of current high-yield wheat can provide all the bread that a family of four eats in 10 years. Another touted wheat as the cheapest food in North America. At 2001 prices, just $90 can provide all the energy needs, protein requirements, and many vitamins and minerals that an individual needs to stay healthy for one year. Wheat is, after all, “the staff of life.” Wheat stores well and can last as long as 30 years in a cool, dry place.
There are three types of wheat. Hard wheat is 15-16 percent protein. Soft wheat is 9-11 percent protein. In North America, soft wheat is generally grown east of the Mississippi and in the Pacific Northwest. Hard wheat needs low humidity, hot days, and cool nights and is grown in Kansas and the Intermountain West. A third type of wheat is durum. Durum is a separate species with hard, high protein kernels, used primarily for pasta.
Hard wheat has a high gluten content and is used primarily for making bread. Softer wheats are used for baking pastries and cakes.
Gluten results from the interaction of two amino acids, glutenin and gliadin, that occurs when flour is moistened with water. Glutenin forms long strands of molecules, and gliadin bridges these strands. When yeast is added in breadmaking, the carbon dioxide released becomes trapped in the glutinous mesh. Industrial baking operations prefer high gluten wheat because bread can be baked in less time, thereby increasing factory output.
Next month, more on wheat and gluten and, of course, gluten intolerance, allergies and celiac disease.
