The breeding method called MutMap has been the collective work of scientists at The Sainsbury Laboratory (TSL) based in the UK, and the Iwate Biotechnology Research Centre in Japan.
Professor Ryohei Terauchi, lead author of the research project from Iwate Biotechnology Research Centre, told FoodNavigator-Asia that work is underway to breed salt-tolerant rice for Japanese farmers.
MutMap had been developed three years before Japan’s Tsunami on March 11 2011, Terauchi said, but following the disaster work commenced on selecting new genetic rice characters that could withstand salt in paddy fields “to meet the urgent demand.”
The professor noted that while a salt tolerance gene has not yet been identified, his team are working on samples and hope to identify the trait within six months and deploy a salt-tolerant rice variety within two years.
Japan’s Agriculture, Forestry and Fisheries Ministry estimated that the Tsunami damaged 23,600 hectares of farmland across six prefectures (the equivalent of roughly 22,000 football pitches) of which, just over 21,500 hectares were rice paddies.
Simple, effective method
Terauchi noted that most importantly, the MutMap technique will enable scientists to dramatically reduce the time it takes to develop new strains of rice from approximately five years to just one.
Firstly the region containing the desired characters is identified, he said, something called ‘gene mapping’. After this, DNA markers are developed to tag these specific genes that can then be followed when breeding new strains.
“MutMap identifies the genomic region containing genes for desired characters in a very short time by using whole genome sequencing. This procedure was very time consuming in the past,” the professor explained.
Whole genome sequencing means that the entire genetic code of a rice sample is read so that the attractive genes can be pinpointed quickly and efficiently. It is done using computerised machines that scan DNA extracted from rice leaves and de-code a series of letters; its genetic code.
Terauchi noted that it is important to cross the desired genes with local, ‘elite’ rice cultivars; those which are high-priced and widely planted in the region.
This means that other traits that make the rice suitable for the growing region do not need to be characterised scientifically, he added.
“Gene mapping was conventionally made by crossing the mutant line possessing the desirable character with a distantly-related cultivar. In MutMap, we cross the mutant line to the parental line, which is simpler,” he explained.
Applying MutMap elsewhere
The research, published in Nature Biotechnology, focuses on “traits of agricultural importance” in rice and covers plant height, leaf colour, starch quality, disease resistance, male fertility, cold tolerance and spike shape.
Terauchi said that since the technique could allow speedy breeding of rice, it could tackle food security concerns globally but ultimately it also has the potential to be applied to other crops that are amenable to whole genome sequencing.