‘Scuba rice’ grows in flood-prone areas

LOS BAÑOS, LAGUNA—The International Rice Research Institute (IRRI) is banking on “scuba rice” to keep Filipino farmers’ hopes afloat even through an increasingly unpredictable climate.

Set to be released to pilot farms nationwide this coming wet season, scuba rice refers to varieties that contain the SUB1 (submergence 1) gene, which enables the crop to survive 10-14 days completely under water.

SUB1 varieties are designed to increase yield in flood-prone areas, according to an IRRI senior scientist.

“We anticipate farmers to like it. It is very suitable for the wet season, for swampy and flood-risk areas,” said Dr. David Mackill of the institute’s Plant Breeding, Genetics and Biotechnology Division.

“[It] can’t obviously solve the whole problem [of rice insufficiency], but it can make a big impact,” he said.

About 15 percent of the country’s rice lands—covering about 300,000 hectares—are considered flood-prone, according to IRRI data.

Scientists have known about the water tolerance characteristic of rice for more than 30 years, but the gene responsible for this was only discovered in the mid-1990s, Mackill added.

Retains taste, texture

FR13A, a rice variety from India, was the original source of the SUB1 gene. In 2003, IRRI began transferring the SUB1 gene to traditional rice varieties through marker-assisted selection, a method that relies on DNA markers in determining a particular trait.

“It’s the same technique for conventional rice breeding [but] is more efficient and quick to precisely introduce the gene with minimum changes in the original characteristics [of the rice],” Mackill said. A similar method is used in transferring genes to boost plants’ resistance to diseases.

Mackill stressed that scuba rice is not a genetically modified variety and that it retains the taste and texture of traditional rice.

A rice variety without the SUB1 gene can only survive underwater for about week, the expert said.

1 to 2 tons more

Also, if planted under similar flooded conditions, SUB1 lines can produce 1 to 2 tons more than the yield coming from varieties without the gene, he added.

“After the field tests, we’re quite confident. We have seen good and consistent results,” Mackill said.

IRRI published its research on the SUB1 gene in 2006. At present, scuba rice varieties include the Swarna-SUB1, IR64-SUB1, RC68-SUB1, RC18-SUB1 and RC82-SUB1.

Already widely produced in India and Bangladesh, the Swarna variety is considered new in the country.

The IR64 is commonly called milled rice in the local market, while the RC18 and RC82 lines are known to Filipino consumers as C4 rice.

Pioneering farm

In the Philippines, SUB1 lines were first planted outside IRRI in 2007 in Barangay Papaya, San Antonio, Nueva Ecija, a low-lying area known to go underwater for three or more days after a rainy spell.

Dr. Romeo Labios, an IRRI consultant, reported that one farmer whose land had lain idle for 15 years produced five tons of rice after being planted to a SUB1 variety. The land was even located near an irrigation canal, he said.

Another farmer who had a 3.5-ha land produced about 5.2 tons, thanks to SUB1, while a third planter with a 2.3-ha land harvested 4.5 tons,” Labios noted.

The SUB1 lines will be tested and then distributed to 18 sites all over the Philippines under the government’s Ginintuang Masaganang Ani (GMA) rice program. Maricar Cinco, Inquirer Southern Luzon

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