Purebred (genetically identical) plant varieties are often less disease-resistant. So, Borlaug cross-bred several lines of wheat with similar observable characteristics to create multiline varieties that are more resistant to diseases. Taller multiline wheat grasses better compete for sunlight, but tend to collapse under the weight of the extra grain. To prevent this, Borlaug bred them with a Japanese dwarf variety to create wheat with shorter, stronger stalks that could better support larger seed heads. The resulting semi-dwarf disease-resistant wheat strains were better suited to tropical and subtropical climates. They also provided dramatically greater grain yields, so much so that the wheat harvest in Mexico increased six-fold within 20 years.
In 1965, Borlaug and his team tried to duplicate the results in India and Pakistan. They tried to export 450 tons of seeds. But, the first shipment was held up in Mexican customs and could not be shipped from a Mexican port in time for planting. Instead, he had it trucked to Los Angeles port. Twelve hours into the ship’s voyage, war broke out between India and Pakistan. Borlaug and his team started planting the seeds as soon as they arrived, often in sight of artillery fire. But, only half the seeds germinated because they had been damaged with pesticides in a Mexican warehouse. So, Borlaug ordered that twice as many seeds be planted at each location instead.
The experiment was a resounding success. In India, wheat yields increased 80% within 5 years. Within 10 years, India was self-sufficient in the production of all cereals. India's use of high-yield wheat has prevented forests the size of California from being converted into farmland. Subsequently, the use of these wheat varieties has also had a substantial effect on wheat production in six Latin American countries, six countries in the Near and Middle East, and several African countries. Borlaug’s work has been aptly called the “Green Revolution”. His work has resulted in food production staying ahead of population growth even as the global population has nearly tripled over the last 60 years.
Norman Borlaug was awarded the Nobel Peace Prize in 1970, as well as the Presidential Medal of Freedom and the Congressional Gold Medal. Yet, his work is not without detractors. He has been criticized for over-reliance on inorganic fertilizers and pesticides. His genetic cross-breeding has been criticized as unnatural, with potential negative side-effects. The use of a small number of monoculture plants has been blamed for decreased biodiversity. These concerns should be used not so much to dismiss his work as to improve upon it.