Materials
For the mapping analysis, seeds of 20 rice plant genotypes
of the BC2
F2
were selected from the previous research and
grown in the glasshouse and let them self-pollinating.
Sixteen to 25 seeds were harvested from each plant, bulked,
and grown individually. A number 331 plants were used for
the genetic analysis including 10 plants from each parents
(P1
= IR64 and P2
= O. rufipogon), 20 plants from the F1,
BCP1, and BCP2 population, and 100 plants from the F2
population. The numbers of plants selected from each
generation were based on their degree of variability in each
generation. Each plant of the populations was evaluated
for their resistance to three races of P. oryzae, i.e. race
001, 033, dan 173. Kencana Bali rice cultivar was used in
the testing as a susceptible control. Selection of the three
races was done based on their dominance in the field and
representing their DNA fingerprints (Utami et al. 2000).