T
he Genetic Enhancement Pro-
gram of the Rio Grande do Sul
Rice Institute (Irga) has been
running, since the 1970s, the
evaluation program of rice gen-
otypes resistant to rice blast in the nursery,
and the cultivars launched are resistant to
outbreaks of the fungus Magnaporthe ory-
zae. The institute evaluates, on average,
seven thousand genotypes for their resis-
tance to the disease. The work is conducted
in a nursery in the interior of Torres, on the
North Coast of Norte do Rio Grande do Sul,
where all the conditions that favor the dis-
ease are created. “Under high pressure, the
varieties are tested, which gives an assur-
anceof their resistance in the field”, says Irga
technical director Maurício Fischer.
The pathogen infests the susceptible
plants in their vegetative and reproduc-
tive phase, where the latter presents the
biggest damages, as it interferes direct-
ly with the grain in its developing stage.
The disease, in severe cases, destroys up
to 100% of the field. That is why, besides
its three resistant varieties to be launch in
the next seasons, the Irga, in a partnership
with the Federal University of Rio Grande
do Sul (Ufrgs), is now developing a project
that intends to monitor the pathogen and
the genetic enhancement of rice for resis-
tance to Phytopathology.
“We are going to conduct a survey of
the Pyricularia oryzae strains that affect
the rice fields in Rio Grande do Sul, along
with the sequencing and the analysis of re-
sistance genes in Irga’s elite-cultivars with
the aim to incorporate this genetic load in
a new cultivar, so as to turn the expression
of this immunity into a durable trait in the
field”, explains Cláudio Ogoshi, researcher
at the institute. The first phase of the proj-
ect has been scheduled for a two-year pe-
riod, but should be one of the permanent
Irga possesses three promising varieties to launch over the next seasons
RESEARCHPROjECTISGOINGTOIDENTIFy
THEFUNGISTRAINSANDTHEGENETIC
RESISTANCETRAITSOFRICEPLANTSWITH
THEAIMTOGENERATEMOREVARIETIES
lines of Irga’s genetic enhancement and
Phyto Technique. The Latin American Fund
for Irrigated Rice (Flar) and the International
Center for Tropical Agriculture (Ciat), based
in Colombia, lend support through the
transference knowledge and genotypes as a
source of resistance to the disease and de-
sirable agronomic characteristics.
Marcelo Gravina de Moraes, PhD in Phy-
topathology and researcher with the Ufrgs,
is responsible for identifying the strains of
fungi present in Rio Grande do Sul. “The ig-
norance about the resistance genes and the
lack of amap of the strains and their behav-
iormake it evenmore difficult to control the
disease. This is why this work is so impor-
tant”, he says. In the scientist’s view, the dis-
ease spread rapidly and reached worrying
levelsofdamageinSouthBrazilbecausethe
pathogen was present, and it found favor-
able environmental conditions and suscep-
tible hosts. “This triangle is a determining
factor and we must learn how to interpret
it with an eye on integrated pest manage-
ment, for example”, he summarizes. He un-
derstands that finding newways is a matter
of time, but the fight between man and the
fungus is going to last for years.
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