Scientist and Nobel Peace Prize winner Norman Borlaug rose from his childhood on an Iowa farm to develop a type of wheat that helped feed the world, fostering a movement that is credited with saving up to one billion people from starvation.
Borlaug, 95, died Saturday from complications of cancer at his Dallas home, said Kathleen Phillips, a spokesman for Texas A&M University where Borlaug was a distinguished professor.
"Norman E. Borlaug saved more lives than any man in human history," said Josette Sheeran, executive director of the UN World Food Program. "His heart was as big as his brilliant mind, but it was his passion and compassion that moved the world."
He was known as the father of the "green revolution," which transformed agriculture through high-yield crop varieties and other innovations, helping to more than double world food production between 1960 and 1990. Many experts credit the green revolution with averting global famine during the second half of the 20th century and saving perhaps one billion lives.
"He has probably done more and is known by fewer people than anybody that has done that much," said Dr. Ed Runge, retired head of Texas A&M University's Department of Soil and Crop Sciences and a close friend who persuaded Borlaug teach at the school. "He made the world a better place - a much better place."
Agriculture Secretary Tom Vilsack called Borlaug "simply one of the world's best. A determined, dedicated, but humble man who believed we had the collective duty and knowledge to eradicate hunger worldwide."
Borlaug began the work that led to his Nobel in Mexico at the end of World War II. There he developed disease-resistant varieties of wheat that produced much more grain than traditional strains.
He and others later took those varieties and similarly improved strains of rice and corn to Asia, the Middle East, South America and Africa. In Pakistan and India, two of the nations that benefited most from the new crop varieties, grain yields more than quadrupled.
His successes in the 1960s came just as experts warned that mass starvation was inevitable as the world's population boomed.
"More than any other single person of his age, he has helped to provide bread for a hungry world," Nobel Peace Prize committee chairman Aase Lionaes said in presenting the award to Borlaug in 1970. "We have made this choice in the hope that providing bread will also give the world peace."
But Borlaug and the Green Revolution were also criticised in later decades for promoting practices that used fertiliser and pesticides, and focusing on a few high-yield crops that benefited large landowners.
Borlaug often said wheat was only a vehicle for his real interest, which was to improve people's lives.
"We must recognise the fact that adequate food is only the first requisite for life," he said in his Nobel acceptance speech. "For a decent and humane life we must also provide an opportunity for good education, remunerative employment, comfortable housing, good clothing and effective and compassionate medical care."
Borlaug also pressed governments for farmer-friendly economic policies and improved infrastructure to make markets accessible. A 2006 book about Borlaug is titled The Man Who Fed the World.
Norman Ernest Borlaug was born March 25, 1914, on a farm near Cresco, Iowa, and educated through the eighth grade in a one-room schoolhouse.
He left home during the Great Depression to study forestry at the University of Minnesota. While there he earned himself a place in the university's wrestling hall of fame and met his future wife, whom he married in 1937. Margaret Borlaug died in 2007 at the age of 95.
After a brief stint with the US Forest Service, Norman Borlaug returned to the University of Minnesota for a doctoral degree in plant pathology. He then worked as a microbiologist for DuPont, but soon left for a job with the Rockefeller Foundation. Between 1944 and 1960, Borlaug dedicated himself to increasing Mexico's wheat production.
In 1963, Borlaug was named head of the newly formed International Maize and Wheat Improvement Centre in Mexico, where he trained thousands of young scientists.
Borlaug retired as head of the centre in 1979 and turned to university teaching, first at Cornell University and then at Texas A&M, which presented him with an honorary doctorate in December 2007.
He remained active well into his 90s, campaigning for the use of biotechnology to fight hunger. He also helped found and served as president of the Sasakawa Africa Foundation, an organisation funded by Japanese billionaire Ryoichi Sasakawa to introduce the green revolution to sub-Saharan Africa.
In 1986, Borlaug established the Des Moines, Iowa-based World Food Prize, a US$250,000 award given each year to a person whose work improves the world's food supply.
He received the Congressional Gold Medal, the highest civilian honour given by Congress, in 2007.
He is survived by daughter Jeanie Borlaug Laube and her husband Rex; son William Gibson Borlaug and his wife Barbie; five grandchildren and six great-grandchildren.