Final answer:
The Green Revolution was the program following World War II that increased grain yield by introducing high-yield, disease-resistant crop varieties and modern agricultural practices, famously led by agronomist Norman Borlaug.
Step-by-step explanation:
Following World War II, the program that increased grain yield by crossbreeding plants and selecting for desirable traits is known as a) Green Revolution. The Green Revolution began in Mexico in the 1940s and spread globally during the 1950s and 1960s, leading to the development of high-response varieties (HRV) of notably wheat and rice. These new plant varieties were designed to increase yield through traits like increased seed production, enhanced disease resistance, and improved tolerance to varying environmental conditions. Alongside the introduction of irrigation, artificial fertilizers, and pesticides, these innovations significantly raised crop yields worldwide, especially in regions facing high population growth and potential famines.
Norman Borlaug, an agronomist, played a pivotal role in this revolution by developing dwarf wheat varieties that were both disease-resistant and high-yielding. Despite the phenomenal success of the Green Revolution in boosting global food production and preventing widespread famine forecasted in the late 1960s, it has also been criticized for contributing to social inequality and environmental concerns.