THE Los Baños-based International Rice Research Institute (Irri) said it is developing rice varieties that are not only tolerant to extreme weather conditions but also produce higher yield.
Dr. Shalabh Dixit, Irri’s trait pipeline lead for marginal environments, said only a few farmers use flood-tolerant rice varieties as its advantages could only be realized during severe flooding situations.
“Farmers always opt for the higher-yielding varieties as compared to flood-tolerant varieties,” Dixit said in a statement.
He said Irri is developing rice varieties “that are not only flood tolerant but also has other desirable rice traits favorable for farmers while maintaining the same crop management practices and applying their known methods in growing traditional rice varieties.”
Dixit explained that some of the common problems of rice farmers in flood-prone areas are pests infestations, crop diseases and income stability.
“If farmers do not feel secure, they will not put enough farm input and instead put these into their savings; this results into lower yield due to insufficient farm inputs. If you can give them the sense of security, then they will apply sufficient farm input,” he said.
Irri said new varieties that could handle multiple stresses like drought, disease resistance, salinity and different types of floods while maintaining, or even producing, higher yield are expected in the future.
Irri developed its first flood-tolerant rice variety in 2008, the IR 64 Sub 1, which came into fruition with the help of a traditional flood-tolerant variety in India.
“This traditional variety exemplifies good submergence tolerance and can survive under water better than normal high-yielding varieties. Genetic studies were conducted using this variety which led to the identification of the Sub 1 gene,” Dixit said.
“The gene was then introgressed into different mega varieties including the IR 64, TDK 1 from Lao PDR, Swarna from India, among others and several sub 1 varieties of these mega varieties was created,” he added.
The IR 64 Sub 1, also known as Submarino 1 (NSIC Rc194), could survive under complete submergence but does not do well under stagnant flooding, according to Irri.
“The stagnant flooding is a condition where water stays more than a month and the lines remain partially submerged. The complete submergence usually happens at seeding-vegetative stage due to typhoons or heavy rains. The anaerobic germination happens in a direct seeding method of planting seed and the field gets flooded, resulting to the poor germination of the rice seed,” Irri said.