By JOJO DE GUZMAN
SCIENCE CITY OF MUÑOZ, Nueva Ecija — The Philippine Rice
Research Institute (PhilRice) has developed a rice variety that could withstand
complete submergence for at least two weeks.
Dr. Leocadio S. Sebastian, PhilRice executive director, said
the new variety, developed by a young plant breeder at the PhilRice Midsayap
branch station in North Cotabato, can withstand continuous submergence up to 28
days.
Tagged as PR33395-27-1-B-B-B, this rainfed elite line is a
cross of Malay 1 and Matatag 1. Malay 1 is an advance upland breeding line,
while Matatag 1 is a tungro resistant and irrigated lowland variety.
This line may very well be one of PhilRice’s answers to the
adverse effects that would be brought about by climate change, which is expected
to lead to greater rainfall variability, resulting in increased frequency of
extreme events like flashfloods in some places.
Even at present, the Philippines already suffers from
frequent typhoons from July to December, which bring in strong winds and excess
water, resulting in continuous flooding.
During this period, 10 to 40 percent of the rice area is
damaged by flashfloods, most especially in Nueva Ecija, Isabela, Cagayan,
Pangasinan, Bulacan, Pampanga, Camarines Sur, Mindoro Occidental, Tarlac, and
Nueva Vizcaya.
Almost all of the popular varieties cannot survive prolonged
submergence of more than three days, resulting in huge losses. Nationwide,
production losses due to flashfloods are valued at an average of P2 million
every year.
PhilRice’s submergence tolerant line has been named Raeline
10, which stands for rainfed advance elite line.
Jonathan M. Nones, the plant breeder, said Raeline 10 is
tungro resistant, has intermediate resistance to bacterial leaf blight, early
maturing (105 days), moderate to shatter ability, and its eating quality is
comparable to IR64.
In screen house tests in cemented ponds in 2006 and 2007,
Raeline 10 had a 100 percent plant survival in 21 days of submergence. In
contrast, the IRRI line IR64-Sub 1 had only 75 percent survival, while Swarna-Sub
1, which was found earlier to survive complete submergence in northern
Bangladesh, did not survive extended submergence.
The screen house tests also showed that the original IR 64
had 50.5 percent survival at 21 days of submergence, while IR 36 and IR 45 had
75 percent like IR64-Sub 1. PSB Rc68 also had 75 percent survival, while PSB
Rc18 had 50 percent.
In a field adaptation trial in Barangay Bulucaon, Pigcawayan, North Cotabato,
a large percentage of the Raeline 10 plants survived 28 days of continuous
submergence under water, while IR64-Sub 1 was almost wiped out.
