Genomic Tools for Breeding Japonica Rice

The majority of cultivated rice can be grouped into two major subspecies: indica and japonica. Recent studies showed that the two rice subspecies evolved from two independent domestication events of the Asian cultivated rice. Japonica rice can grow in both temperate and tropical regions unlike the indica subspecies. The genetic diversity of the japonica subspecies, however, is narrower compared to indica rice. In order to develop high yielding and stress tolerant varieties, the japonica rice germplasm must be diversified. A review paper published by the journal Molecular Breeding discusses recent genomic approaches to assist breeding in the japonica subspecies.

Researchers can locate useful genes in indica as well as wild rice relatives using the full sequence of the rice genome and the available tools offered by genomics. Such tools include EcoTILLING, a high-throughput procedure of screening mutants for sequence differences in known genes, and microarray-based genotyping. Useful genes can be incorporated to commercial japonica varieties through marker-assisted breeding. The author suggests that breeding strategies successfully employed in indica rice breeding, such as idiotype breeding and wide hybridization, might also be applied in japonica rice improvement.

The abstract of the paper, including links to the full article, is available at http://www.springerlink.com/content/h70810v82521552j/?p=ae31797184e847199e890c0a15b94189&pi=4