The Green Revolution and Wheat Genetic Diversity: Some Unfounded Assumptions uri icon

abstract

  • Two propositions have become common assumptions in the development literature: (a) the Green Revolution caused genetic erosion, and (b) the Green Revolution increased genetic vulnerability. With regard to the first proposition, no causal relationship between the Green Revolution and genetic erosion can be established for bread wheat given the difficulties in measuring genetic erosion and of demonstrating causality. The pattern of genetic variation in farmers' wheat fields has undoubtedly changed over the past 100-200 years with increasing cultivation of varieties released by plant breeding programs, but the implications of these changes for the scarcity of useful genetic resources are unclear. With regard to the second proposition, evidence suggests that since the early years of the Green Revolution, the concentration of wheat area in leading cultivars has declined. The semidwarf wheats of the Green Revolution were also less vulnerable to rust diseases than the tall varieties previously released by plant breeding programs as well as traditional varieties. Although rust, diseases continue to pose a challenge to wheat scientists, their understanding of the genetic basis of resistance has increased over time. The percentage of area planted to leading wheat cultivars remains a cause for concern, however, and social scientists need to understand better how various policies affect the spatial distribution of cultivars. (C) 1997 Elsevier Science Ltd.

publication date

  • 1997
  • 1997