Johnston and Mellor’s vision of a broad-based yet labor-intensive technological change in Asian agriculture was to materialize in the form of the “Green Revolution”. The ex post impact of the Green Revolution have been evaluated by Evenson and Gollin (2003), in a Science paper. The Green Revolution began with the introduction of varieties of wheat and rice that could respond to greater application of fertilizer and water with much higher yields. Dissemination of improved varieties of rice, wheat, and corn became widespread in the 1960s and 1970s, while varietal improvement programs also began for other crops.
Yield of cereals, roots and tubers, and pulses jumped dramatically. From 1961 to 1980, production of these crops grew by 3.65% per year in developing Asia; only 14% of this can be attributed to area expansion – the rest is due to yield increases. Of the latter, the contribution of the improved variety was 22%, and the remainder is attributed to input intensification.
Food model simulations indicate that in the absence of a Green Revolution, crop yield and production in developing countries would have been much smaller compared to the actual figure for 2000, and agricultural area higher. Conversion of natural habitats to farm area would have had adverse environmental impacts: Lower supplies would have meant more expensive food and decreased calorie intake.