More popularly called PJ21, the new variety has been released by the National Seed Industry Council as NSIC Rc134 or Tubigan 4. Nationwide evaluation of the variety was conducted by the PhilRice-led Rice Varietal Improvement Group.
Most rice varieties released by the NSIC in the past suited to either transplanted culture or direct seeding.
PhilRice and JICA rice breeders crossed japonica and indica varieties to exploit their hybrid vigor and then incorporated the excellent grain and eating qualities of the offspring with leading varieties in the Philippines.
PhilRice plant breeder Thelma F. Padolina said PJ21 is a progeny of the cross coded as PR26673-6-Bs. Padolina and her co-workers crossed a Japanese variety, Sasanishiki, with IR64 and then crossed the offspring with Burdagol, resulting in PJ21.
The other workers were Hilario C. dela Cruz Jr., Emily C. Arocena, Takehiko Sasaki, Kunio Moriya, Julieta F. Parinas, J. Dancel, Virgilio M. Alata, Teresita A. Alegado, Dr. Rodante E. Tabien and Dr. John C. de Leon. Both Sasaki and Moriya are Japanese rice breeders dispatched by JICA to PhilRice.
PJ21 showed better performance than IR64 in year 2000 dry and wet seasons. It showed fairly high yielding ability in the advanced observation nursery with 6.56 tons per hectare (T/ha) and in the preliminary yield trial with 8.2 t/ha. It performed much better than IR64 by at least 30 percent in the PYT.
It was tested nationwide in the multi-adaptation trials from 2003 to 2004 in 22 sites.
Padolina said PJ21 was initially developed for transplanted culture, but its adaptability to direct wet-seeded culture was observed by accident while it was already being tested in the NCT.
In seven sites in the multi-adaptation trials for transplanted culture, PJ21 produced the fourth highest yield among the lines tested, while the yields of the check varieties were only No. 9 and No. 12. Its average yield was also statistically higher in Davao and Isabela.
Under direct wet-seeded culture, PJ21 also produced the third highest yield among the lines tested. Its yield was exceptionally higher than PSB Rc28, the check variety. Its yield performance remained high in the wet season.
Even in farmers’ fields managed by researchers, PJ21 also produced high yields with an average 5,350 kilograms per hectare (Kg/ha) under transplanted culture and 5,380 Kg/ha under direct wet-seeded culture.
PJ21 also has the following qualities: good grain and eating qualities just like its parents IR64, Burdagol and Sasanishiki; intermediate resistance to blast, bacterial leaf blight, and sheath blight; moderate resistance to deadhearts; and intermediate resistance to whiteheads, green leafhopper, and yellow stemborer.
It is early maturing and, hence, would be very useful in rice-based farming systems where farmers want to plant a second crop after rice and make use of the residual moisture. Its good grain and eating qualities are also valuable traits for consumers’ acceptability and preference.