The reactions of rice
bacterial leaf blight races were identified in Guilan province—Iran on 12 near-isogenic
lines and 14 pyramiding lines from International Network for Genetic Evaluation
of rice (INGER) and 8 local and improved Iranian varieties were evaluated under
natural photoperiod condition in the field. Inoculation was done at panicle
initiation by clipping the sterilized scissors in the bacterial suspension to
booting stage. Scoring of inoculated plants was made 21 days after inoculation.
Infection levels of pyramiding lines containing two to five resistance genes,
expect, IRBB53 and IRBB61 with respectively resistance gene combination, Xa5 + Xa13
and Xa4 + Xa5 + Xa7, were not so clear. Among near-isogenic lines IRBB1, IRBB2,
IRBB4 and IRBB10 carrying resistance gene Xa1, Xa2, Xa4 and Xa10 were
susceptible; IRBB8, IRBB11, IRBB3, IRBB5 and IRBB13 were moderately susceptible;
(having resistance gene Xa8, Xa11, Xa3, Xa5 and Xa13) IRBB14, IRBB21 and IRBB7
with respectively resistance gene Xa14, Xa21 and Xa7 were moderately resistance
to bacterial blight. Furthermore, most of the time gene combinations support
the strategy of pyramiding appropriate resistance gene. Local varieties were
more susceptible than improved varieties to leaf blight disease. Among local
varieties, Tarom was the most susceptible. And
also, there were no significant differences among improved varieties and all of
them were moderately resistance.