Nutricion

Assessing the Impact of the Green Revolution, 1960 to 2000

Assessing the Impact of the Green Revolution, 1960 to 2000 The development of modern or high-yielding crop varietiesfor developing countries began in a concerted fashion in the late 1950s. In the mid-1960s, scientists developed modern varieties of rice and wheat that were subsequently released to farmers in Latin America and Asia. ‘Thrashing Grain’, wood engraving by Somnath Hore, North Bengal 1946. The success of these varieties was characterised as a‘Green Revolution.’ The following are extracts from a paper by R.E. Evenson and D. Gollin, ‘Assessing theImpact of the Green Revolution’, published by Science on 2 May 2003. For the full paper, go to www.sciencemag.org/cgi/content/full/300/5620/758Early rice and wheat modern or high-yielding varieties (MVs) were rapidly adopted in tropical and subtropical regions with good irrigation systems or reliable rainfall. These MVs were associated with 2 of the 16 major international agricultural research centres (IARC) operating under the auspices of the Consultative Group on International Agricultural Research (CGIAR). These centres currently support about 8500 scientists and scientific staff, and the annual budget of the CGIAR is currently around $340 million. A recent study initiated by the Special Project on Impact Assessment of the CGIAR's Technical Advisory Committee compiled the most extensive data yet assembled on the breeding, release, and diffusion of MVs. The study found the following.

(1) Gains from MVs were larger in the 1980s and 1990s than in the preceding two decades—despite popular perceptions that the Green Revolution was effectively over by this time. The Green Revolution is best understood not as a one-time jump in production, occurring in the late 1960s, but rather as a long-term increase in the trend growth rate of productivity. This was because successive generations of MVs were developed, each contributing gains over previous generations.

(2) The MV contribution to yield growth was higher in the late than in the early GreenRevolution period, accounting for almost 50% of yield growth and 40% of production growth for all developing countries. This indicates that in the late Green Revolution period, production gains were more dependent on MVs than in the early period, and that MVcontributions were greater in the late period.

(3) Contrary to some views of the Green Revolution, the rate of MV releases has actually increased since the 1960s.

(4) More than 35% of MVs released and adopted were based on crosses made in IARCs; 15% of MVs crossed by the national agricultural research systems of developing countries (NARS) had an IARC-crossed parent, and an additional 7% had another IARC-crossed ancestor.

(5) IARC research complemented NARS breeding. By providing improved germplasm for NARS breeding programmes, international breeding efforts increased the productivity of national programmes. Because of this IARC-NARS complementarity, the existence of the international centres actually stimulated national investment in NARS research.

(6) Although input use intensified in the late Green Revolution period, productivity gains from MVs allowed food production to increase dramatically with only modest increases in areaplanted to food crops—and with relatively slow growth in the use of inputs such as fertiliser and irrigation.

(7) In the absence of international research, the world would have experienced a ‘human welfare’ crisis, with caloric intake per capita in the developing world 13.3 to 14.4% lower, and the proportion of children malnourished from 6.1 to 7.9% higher. This suggests that the Green Revolution raised the health status of 32 to 42 million preschool children and cut infant and child mortality.

(8) Assessments of the impacts of IARC and NARS programmes showed very high benefit:cost ratios for IARC

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