The Evolutionary Story of Four Vital Crops
July 6, 2016
Without plant breeding, we would have little to eat and what we did have, wouldn’t be very tasty or nutritious. Most of the crops familiar to us today didn’t even exist in the wild! Humankind has been breeding plants for 10,000 years to improve yield, quality and taste and plant breeders today continue to improve crops with modern tools like biotechnology.
Around 6,000 years ago Mesoamerican farmers selectively bred maize (corn) from teosinte, a grass that looks little like today’s crop. Teosinte was only two or three inches long with 12 hard kernels versus modern maize’s 500+ soft kernels. Teosinte kernels could crack teeth, so the earliest plant breeders chose varieties that produced softer kernels for cultivation. Since the beginning of agronomy, plant breeders have selected crop varieties for increased production and nutritional quality, resistance to pests and diseases, and improved appearance and taste.
Many early civilizations and pre-industrial societies were built on maize. In 2,500 BC, further improvements in the crop allowed for major pre-Columbian civilizations to form. After discovering and trading with the Americas, Europeans began to breed maize for local production, which had mixed kernel colors and later, an all-yellow variety was developed in France. Variations of yellow corn have since been developed around the world, including biotech varieties that are insect-resistant and herbicide- and drought-tolerant for enhanced production.
Today, nearly 60 million hectares of biotech maize is grown, accounting for 30 percent of the total crop globally. Top biotech maize producers are the United States, Brazil, Argentina, South Africa and Canada.
The domestication of wheat began 10,000 years ago, starting with wild einkorn and emmer wheat. Over time, crosses between these plants and various grasses resulted in wheat as we know it today. This allowed humans to settle down and form large communities.
Wheat remained virtually unchanged until Nobel Laureate and agronomist Norman Borlaug developed tougher, disease-resistant varieties in the mid-1940s-50s. His semi-dwarf wheat [link to story below] sparked the “Green Revolution” around the world, which demonstrated the impact plant breeding can have on crop productivity and yields. Borlaug’s improved wheat varieties helped to save over a billion people from starvation.
Plant scientists are currently working on biotech wheat varieties to improve resilience to pests, drought, and other undesirable growing environments.
The ancestors of rice originate from India but were first domesticated in China, with records showing that rice paddies were grown as far back as 4,000 BC in wet conditions in the Yangtze River valley; dryland varieties existed elsewhere. Both types are around the world today – each with its advantages adapted for certain climates.
Rice did not change very much until Dr. Norman Borlaug and M.S. Swaminathan brought the Green Revolution to Asia with high-yielding varieties of rice with shorter and stronger stalks. This first variety was known as ‘IR8.’ This rice grew faster because its height requirement to produce grain was shorter. It could also produce more rice and be harvested by machine.
Today, there are flood- and drought-resistant varieties of rice that are credited with the “Second Green Revolution” in Asia. Plant scientists have also developed biotech herbicide-tolerant rice to control weeds, which has been approved for commercialization in North America. Scientists are working as well on biotech rice varieties with resistance to insects, diseases and abiotic stresses such as drought, salinity and extreme heat.
The potato was domesticated by the native South Americans in the Andes mountains some 7,000-10,000 years ago. It could be grown in almost any climate in a short season and stored for long periods of time.
There are thousands of potato varieties but globally, only a few are consumed. Varieties have been chosen based on cultural preferences. For example, because ‘Russet Burbank’ and ‘Yukon Gold’ potatoes are good for making fries, the United States grows more of them than blue, fingerling or thousands of other kinds found in Peru.
Plant scientists have created biotech potatoes that don’t bruise or brown and produce less of an undesirable compound (recently commercialized) as well as varieties with insect resistance (yet to be commercialized). Researchers are also developing biotech traits for reduced black spots, disease resistance and enhanced cold storage capability.