From gene to adaptation in rice
2007
Onishi, K. | Sano, Y.
The recent accumulation of information on plant genomes has enabled us to study adaptive traits at both the phenotypic and molecular levels. Genetic diversification is a consequence of the existence of a diverse set of environments. Plant breeding will accelerate the rate of micro-evolution in our changing world. To understand ongoing micro-evolutionary processes, genetic alterations in response to temperature, photoperiod, and biotic environments were investigated in wild and cultivated rice. These adaptive mechanisms were not well explained by a few major genes, suggesting that epistasis, genotype x environment (GE) interaction, and linked genes were involved in addition to genes with a small additive effect. Genetic diversity is affected both by current patterns of micro-evolutionary forces, such as gene flow of selection, and by phylogenetic history. Genealogies of agronomic genes provided insight into their history. Unexpectedly, the 'Green Revolution' gene (sd1) preexisted in the wild ancestor, showing that farmers selected it to obtain a high yield in response to altered practices in agriculture. In contrast, in the case of C, A, and wx genes, variants were generated from landraces through natural or artificial selection, suggesting that each of the genes my have its own history.
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