Government rice breeders had perked up the yield potential of high-yielding inbred rice IR 64 through the development of its bacterial leaf blight (BLB) resistance using a new technology called "molecular marking".

The first conventionally-bred BLB-resistant inbred to be developed through molecular marking, NSIC RC142 or Tubigan 7 had been recommended for commercial release by the National Seed Industry Council (NSIC).

Tubigan 7 has the inherent advantage most farmers look for as BLB (manifested by leaf wilting) can wipe out a conservative 40 percent of yield particularly in irrigated lowland, and even more severely in the wet season. The best inbred can give a yield of five to six metric tons (MT) per hectare at the highest, and BLB-resistance keeps that yield advantage.

Since it is inbred, the IR 64 cross Tubigan 7, developed by the Philippine Rice Research Institute (PhilRice) led poor farmer does not need to buy the seed each time he plants it, making rice production cost cheaper for him.

It may even be an instrument for the Philippines' raising its sufficiency rate now that rice import is climbing.

The good thing about the use of molecular marking is it is a conventional breeding process that identifies a rice specie's good traits through amplification of DNA (genes that carry inherited traits). Thus, it veers breeders away from rigid, time-consuming, and costly biosafety regulations.

"Through a submicroscopic device, we can amplify some portions of DNA and see bands under UV (ultraviolet) light. If a long band is associated with the resistance trait, the plant with that long band will be the one tested," said Dr. Antonio A. Alfonso, PhilRice biotechnology chief, in an interview.

Molecular marking is saving breeders lengthy time for developing a desired trait. Under conventional breeding, a rice specie has to go through seeding stage (25 days) and it needs another 45 days from transplantation to be tested for BLB resistance.

To determine if the plant is susceptible or resistant to BLB, another 14 days to 21 days is needed to determine if the plant reacts to the pathogen implanted by breeders after inoculating (immunizing) it.

However, with molecular marking, only 20 days from seed germination is needed to test the plant.

"If you have a laboratory, you can do thousands of trials. You can do it at very early stage," he said. With conventional breeding, "you are limited by your land (capacity)."

A further advantage of molecular marking technique is it retains important traits of a backcrossed variety, in this case IR 64's good milling, eating, and physical qualities, low amylose content (indicating softness, moist, stickiness upon cooking).

Tubigan 7 even has intermediate resistance to major rice pests and diseases - sheath blight, stem borers, green leafhopper, and brown plant hopper.

PhilRice's acquisition of molecular marker device which includes a set-up for gel electrophoresis, (device where plants' band characteristics are exhibited through the gel on DNA) cost almost P1 million. It was funded by the Rockefeller Foundation and Asian Development Bank through the "Asian Rice Biotechnology Network", a project for Asian countries.

Phirice is now using the same molecular marking technique in developing other desired rice traits including tungro-resistance, pro-Vitamin A-enrichment in rice (Golden Rice), blast resistance, and submergence tolerance (plants' survival under flooding in 10 to 14 days) which will help farmers in flooded areas.

PhilRice is hoping the development of the BLB-resistant rice that will enhance farmers' income and even raise the country's rice production which at 14.6 million MT (only 9.49 million MT when milled) in 2005 still falls far short of the country's requirement which must be reaching to 11.3 million MT in milled form.