Manila, The Philippines
December 28, 2006
By Sosimo Ma. Pablico,
The Philippine STAR via
The first biotech rice variety in the Philippines, released only
recently by the National Seed Industry Council [NSIC] for
commercial production, is now being produced in a large scale.
Called NSIC Rc142 or Tubigan 7, the new rice variety is the
country's first product of a mid-level biotech technique called
marker-aided selection. It is resistant to the dreaded bacterial
leaf blight (BLB) disease, which is serious during the wet
Tubigan 7 is one of the offsprings produced in almost 10 years
of rigorous breeding work initiated in 1995 by Dr. Leocadio S.
Sebastian, PhilRice executive director, through a research grant
from the Rockefeller Foundation. It is the first variety
produced by the project.
Subsequent breeding works were handled by Dr. Rodante E. Tabien,
MC Abalos, MP Fernando, Emily C. Abrogena, Yolanda A. Dimaano,
GM Osoteo, Rolly C. San Gabriel, DA Tabanao, Thelma F. Padolina,
Herminia Rapusas and Genero P. Rillon.
The BLB resistance of Tubigan 7 was derived from IRBB5-21, a
line provided by the Asian Rice Biotechnology Network (ARBN) of
the International Rice Research Institute (IRRI).
According to Sebastian, Xa21, the BLB resistance gene from
IRBB5-21, is known to be effective against nine BLB races. It
was introduced into IR64 using DNA markers, as IR64 is
considered a good parent for yield and grain quality. The DNA
markers help plant breeders locate genes of interest, usually
those that are associated with desired traits like BLB
Through the use of DNA markers, plant breeders can readily
identify the offspring [products of breeding work] that are
resistant to the much dreaded disease without waiting for the
plants to grow until a particular stage.
Dr. Antonio A. Alfonso, PhilRice plant breeding and
biotechnology division head, said the use of DNA markers makes
the selection of BLB-resistant plants easier, faster and more
effective than the conventional breeding method.
In the conventional breeding method, BLB-resistant plants are
selected at around 45 days after transplanting. This method
requires that the plants are inoculated with the disease
organism that causes BLB and then observed for disease
occurrence after two to three weeks for eight to nine weeks.
In contrast, plant breeders using marker-aided selection do not
need the tedious process in conventional breeding. All they need
is to identify plants with the BLB resistance gene and then
evaluate and select them in the screenhouse and in the field. As
a result, "breeding efficiency is tremendously increased due to
reduced cost owing from reduced number of test entries and time
needed for selection," Alfonso said.
"The use of DNA as markers for selection has streamlined and
facilitated the whole process even without inoculation," Tabien
and his co-workers said earlier in a paper presented during the
13th national rice research and development conference in year
Actually, marker-aided selection started in the 1996 wet season
and continued until the 1998 wet season. Field testing started
in the 1999 dry season.
In the National Cooperative Tests Phase 1, the yield of Tubigan
7 under direct wet seeded culture was 24 percent higher than PSB
Rc30 during the dry season and 32 percent higher during the wet
season. Under transplanted condition, its yield was higher by
Although Tubigan 7 is more adaptable in direct wet seeded
culture, it could also be used in transplanted culture,
preferably during the wet season. The breeders, however, suggest
that it should be frequently monitored for blast incidence.
This new variety matures early at 105 days with a height of 85
centimeters. It has intermediate resistance to major diseases of
rice like BLB and sheath blight, as well as a wide spectrum of
resistance to the insect green leafhopper, yellow stemborer and
brown planthopper. Green leafhoppers transmit the tungro virus
disease, while brown planthoppers could wipe out a whole crop
under heavy infestation.
Tubigan 7 has good milling and eating qualities, as it is sticky
and moist when cooked because of its low amylose content.