HONG KONG // A gene that raises rice yields by enhancing root growth and nutrient absorption in poor soils has been identified in a species of rice in India and successfully introduced into other rice varieties, researchers said last week.
Scientists and rice breeders have known for years that Kasalath rice is unusually efficient at nutrient absorption, but only now have they succeeded in identifying the gene responsible.
In a paper published in the journal Nature, they described how they identified the gene after analysing part of the Kasalath DNA where the gene was thought to be located and comparing it with other rice varieties without the trait. Using conventional breeding methods, they introduced the gene into a few rice types in Indonesia, the Philippines and Japan and found that it raised yields by up to 20 per cent.
"We found a gene that enhances phosphorus uptake in low phosphorus conditions. We have been looking for it for many years," said the lead author, Sigrid Heuer, at the International Rice Research Institute in Manila.
She said the superior breeding lines could be released to farmers in Indonesia in two to three years. These lines have already been developed using conventional breeding methods - by pollinating the flowers of a native Indonesian rice species with pollen from the Kasalath.
"As for other Asian countries, we will get them to put the gene into their local varieties through conventional breeding" over the next four to five years, Ms Heuer said.
By using conventional breeding techniques, in this case, cross-pollination, there are no issues related to genetic modification. Food safety concerns and regulatory hurdles for transgenic rice (where a gene is physically inserted into plant DNA in a laboratory) can translate into years or even decades of testing before the strain reaches markets
The gene, PSTOL1, allows rice crops to thrive in soil that has low levels of phosphorus, a nutrient that promotes root growth, winter hardiness and hastens maturity. Plants deficient in phosphorus are often stunted.
"If you have a bigger root system," Ms Heuer explained, "then the plant can take it up better and they can have better access to the patches where the phosphorus is."
