A new rice variety, developed by a leading rice-research agency in Asia, for flooded, low-lying fields promises not only of enduring flood water but also of resisting the three known most dreaded rice pests—bacterial blast, tungro and stemborer.
The scientists involved in breeding the new Tubigan 7 rice variety used the DNA marker-aided selection (MAS) technique in identifying the genes for each desired traits of submergence tolerance and resistance to pests.
"Instead of the usual laboratory tests, the breeders took pains in identifying the genes to come out with the target characteristics of the variety," said Dr. Antonio Alfonso, head of plant breeding and biotechnology division of the Philippine Rice Research Institute (PhilRice) in Muñoz Science City in Nueva Ecija, which initiated the development of Tubigan 7.
Alfonso emphasized, however, that Tubigan 7 is not a genetically modified rice. "These [genes involved] are not transgenic. Source of genes were still rice and [the method was] made through conventional breeding," he said.
Tubigan 7, which means "flooded," in the vernacular, is an elite line with IR64 background. It also has fertility restorer trait and could yield about 8 tons per hectare during the dry season cropping and 5 to 6 tons per hectare during the wet season, 15 percent higher than the conventional harvest record in the Philippines.
PhilRice said Tubigan 7 is "the first-ever successful DNA-MAS product in the Philippine rice breeding."
This is also the second locally developed biotechnology rice, the first being the tissue culture-derived variety of improved traditional wagwag, Antonio said.
PhilRice completed the Tubigan 7 breeding process in June 2006 after nearly a decade of testing series, and recently the Philippine National Seed Industry Council (NSIC) officially released it as a variety.
The scientists involved in the project—Rolando Tabien, Marilou Abalos, Maricar Fernando, Emily Corpuz, Yolanda Dimaano, Gloria Osoteo, Rolando San Gabriel, Dindo Tabanan, Herminia Rapusas, Juliet Rillon and Leocadio Sebastian—cross-combined 103 genes with BB-, tungro-, and stemborer-resistance traits, as well as earliness genes during the dry season.
After they made additional crosses during the wet season—14 of them were for tungro-resistance and five for BB-resistance.
Alfonso explained that to come out with the flood-tolerant gene, the scientists applied the DNA-MAS crop breeding technique, which is direct extraction of DNA from each plant in the test field to determine which of the plant is resistant and which is susceptible to bacterial blight instead of the usual laboratory test.