“Waterproof” versions of popular varieties of rice, which can withstand 2 weeks of complete submergence, have passed tests in farmers’ fields with flying colors. Several of these varieties are now close to official release by national and state seed certification agencies in Bangladesh and India, where farmers suffer major crop losses because of flooding of up to 4 million tons of rice per year. This is enough rice to feed 30 million people.
The flood-tolerant versions of the “mega-varieties”—high-yielding varieties popular with both farmers and consumers that are grown over huge areas across Asia—are effectively identical to their susceptible counterparts, but recover after severe flooding to yield well.
The new varieties were made possible following the identification of a single gene that is responsible for most of the submergence tolerance. Thirteen years ago, Dr. Mackill, then at the University of California (UC) at Davis, and Kenong Xu, his graduate student, pinpointed the gene in a low-yielding traditional Indian rice variety known to withstand flooding. Xu subsequently worked as a postdoctoral fellow in the lab of Pamela Ronald, a UC Davis professor, and they isolated the specific gene—called Sub1A—and demonstrated that it confers tolerance to normally intolerant rice plants.
Dr. Ronald’s team showed that the gene is switched on when the plants are submerged. Sub1A effectively makes the plant dormant during submergence, allowing it to conserve energy until the floodwaters recede.
As a long-time geek, it’s nice to see that a significant piece of the funding for the research that developed this strain of rice came from the Bill and Melinda Gates Foundation.
