A team of Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) plant industry scientists have isolated the gene that produces the shorter, more productive varieties of rice that led the ‘Green Revolution’ of rice varieties in the 1960s.
According to team leader Dr. Wolfgang Spielmeyer, isolating the gene will speed up the process of breeding new rice varieties and help to identify semi-dwarfing genes in other cereal crops, such as wheat.
"In terms of yield, the ‘green revolution’ gene is probably the single most important gene in modern rice breeding," Spielmeyer said. "Today it is still the main semi-dwarfing gene present in most rice varieties but, until now, it has never been isolated."
The ‘Green Revolution’ saw new varieties of rice with shorter stems producing record crop yields throughout Asia. The semi-dwarf varieties were less likely to fall over and responded better to nitrogen fertilizers.
The research team was able to isolate the ‘semi-dwarfing’ (sd-1) gene, and develop markers to identify it by using information from the publicly available rice genome sequence and with funding from Graingene, a strategic alliance between Australia’s AWB Limited, CSIRO and the Grains Research and Development Corporation (GRDC).
"Because we were able to use the publicly available rice genome sequence, we were able to isolate this gene significantly faster than by conventional methods," Spielmeyer said.
Once the semi-dwarfing gene had been isolated, Spielmeyer’s team developed a perfect marker directly from the gene sequence that will enable rice breeders to produce new varieties of semi-dwarf rice more efficiently.
"A perfect marker is like a molecular flag," he explained. "It is an easily detectable piece of DNA that identifies a gene, or group of genes. In this case, it marks the location of the sd-1 gene for semi-dwarfing."
The perfect marker developed by Spielmeyer and his team will fast-track breeding of new rice varieties by enabling breeders to screen for the semi-dwarfing gene at a much earlier stage of plant development, saving valuable time and resources.
"We will be able to use our knowledge of the sd-1 gene to study and isolate related gene sequences that are responsible for semi-dwarfing in other cereal crops, such as wheat and barley," he said. "We hope this will lead to further advances in improving these important crops."