Farmers no longer have to worry about low yield caused by water-related stress as the Philippine Rice Research Institute (PhilRice) has developed some stress-resistant rice varieties.
Christopher Cabusora, a plant breeder of the PhilRice Plant Breeding and Biotechnology Division, explained in a seminar titled “Variety Development Adapted to Adverse Rice Environments through Induced Mutation” held at the PhilRice Central Experiment Station on March 8 that rice varieties are highly vulnerable to abiotic (particularly water-related) stress, such as drought, submergence, and salinity (concentration of salt dissolved in a water). If not well managed, abiotic stress according to the researcher can cause a yield loss of 17-50%.
Cabusora said their project “Rainfed-Stress Breeding” has produced rice varieties that are drought and saline resistant. Now available for commercial cultivation, the drought-resistant varieties are: Sahod Ulan 2 with an average yield under stress condition of 3 tons per hectare, Sahod Ulan 11 (3.2 t/ha), Sahod Ulan 16 (3.4 t/ha), Sahod Ulan 18 (3.7 t/ha), and Sahod Ulan 22 (3.3 t/ha). The saline-resistant varieties are: Salinas 6 (3.6 t/ha), Salinas 7 (3 t/ha), Salinas 8 (2.9 t/ha), Salinas 14 (2.3 t/ha), Salinas 213 (t/ha).
“These varieties are more advantageous (under stress environments) compared to common varieties because they can thrive under adverse environments, not to mention can give high yield for farmers,” Cabusora explains.
The process by which the varieties are developed called induced mutation was also highlighted during the seminar. As explained by Dr. Nenita Desamero, leader of the breeding project, induced mutation is a method of breeding specifically done to produce mutants (variant lines) that can adapt to adverse environments like rainfed-drought prone, submerged, and saline areas.
“One advantage of using biotechnology, such as induced mutation, is that it can produce improved stable lines rapidly. Doubled haploid breeding, another biotech tool, is a technique that can reduce the breeding cycle by up to six years, compared to conventional breeding,” Cabusora adds.
Cabusora added that the PhilRice breeding team also presented 258 promising mutants with multiple abiotic stress tolerance and 22 elite mutant lines ready for National Cooperative Testing (NCT) nomination, 11 mutant lines currently evaluated by NCT, three lines with distinct traits for Plant Varietal Protection (PVP) application, and 12 rice tungro resistant lines for validation.
Cabusora also emphasized the importance of breeding stress-resistant varieties in helping the farmers enhance their yield in rice farming under stress condition.
“A farmer’s aim is to gain income, and as rice breeders, our goal is to help them achieve that by producing varieties like these. The best thing about these stress- resistant varieties is that whether there is stress or none, they can still produce yield no matter what,” Cabusora stresses.
There are also 11 stress-resistant mutant varieties from the Philippines that are registered on the International Atomic Energy Agency (IAEA) Mutant Variety Database (MVD). These are: BPI-121-407, PARC 1, PARC 2, BPI Ri-10, PSB Rc 78, Milagrosa mutant, Azmil mutant, Bengawan mutant, PR22902, NSIC Rc272 (Sahod Ulan 2) and NSIC Rc346 (Sahod Ulan 11). The last two varieties were bred by PhilRice.