Genetics not a key driver of yield
The Rubisco enzyme and agricultural productivity
Correspondence, Nature 463, 876 (18 February 2010) | doi:10.1038/463876b; Published
online 17 February 2010
John R. Porter1 & Bernd Wollenweber2
1 Department of Agriculture and Ecology, University of Copenhagen,
2630 Taastrup, Denmark
2 Department of Agricultural Science, University of Arhus, Denmark
Improving Rubisco's carbon-dioxide-fixing capability by genetic engineering is unlikely to enhance crop productivity significantly on its own (R. J. Ellis Nature 463,164 165; 2010).
Crop yield does not depend on a single enzymatic reaction: it is the result of a population-scale process that is the outcome of a series of source and sink regulated developmental and growth processes (R. K. M. Hay and J.R. Porter The Physiology of Crop Yield, Wiley-Blackwell, 2006).
The success of modern, high-yielding crop varieties is mainly down to their larger leaves, which intercept more light and provide more shade against competitive weeds. The management and agronomy of crops are typically more important as drivers of yield than genetics. They also make crop production more sustainable.
Crop physiologists have appreciated for a long time that to increase growth, increases in photosynthetic rate are accompanied by higher respiration costs because more growth substrates and more proteins have to be constructed.
The idea that respiration and photorespiration are a drain on crop dry-weight production was dropped by crop physiologists many years ago.
Genomics, proteomics and metabolomics may increase our understanding of the regulation of different physiological processes and mechanisms of resistance to stress, but they do not show us the bigger picture. A recognition of the balance and interactions between genotype, environment and management is the intelligent solution to feeding the growing global population.
John R. Porter, Department of Agriculture and Ecology, University of Copenhagen, 2630 Taastrup, Denmark
Bernd Wollenweber, Department of Agricultural Science, University of Arhus, Denmark