These early breeding techniques resulted in large yield increase in the United States in the early 20th century.
As the price of the stock declines, the yield increases.
In Virginia a five-year experiment saw yield increase of 35% in fields treated with fluazinam.
The development of the banana export industry has been accompanied by dramatic yield increases.
The annual yield increase is enough to feed 60 million people.
However, ear-row breeding did not result in large yield increases and was largely abandoned after a few years.
At the same time the corresponding increases in agricultural land-use intensity raises costs for further yield increases.
In the mid-1970s farmers began to plant hybrid rice, claiming yield increases of more than 20 percent.
Under optimum conditions of temperature and humidity, the yield increase could reach 36%, if the levels of carbon dioxide are doubled.
One study found that applying cytokinin to cotton seedlings led to a 5-10% yield increase under drought conditions.