The mean grain yield of parents and lines over each season is
presented in Table 2. Under the upland stress in 2004 and 2006,
yield reduction in susceptible parent IR64 ranged from 78 to
100%. Way Rarem, the other susceptible parent, had a yield
reduction of 86–90%. The tolerant parent IR55419-04 had a yield
reduction of 65–72% in 2004 and from 80 to 88% in 2006. A
higher level of stress in 2006 than in 2004 resulted in a higher
reduction in the grain yield of these parental lines. The higher
stress in 2006 than in 2004 is also evident from the mean yield of
the stress trial, which was lower in 2006 than in 2004 (Table 2).
In 2005, the upland stress experiments were exposed to a
much lower level of stress than in both 2004 and 2006. In 2005,
the mean reduction in yield of susceptible parents IR64 and
Way Rarem ranged from 32 to 71% and 44 to 50%, respectively,
whereas it was from 24 to 34% for the drought-tolerant parent
IR55419-04. The mean reduction in trial yields were 32 and
33% in both populations (Table 2).
In the lowland stress experiments at Raipur, the mean
reduction in yield under drought stress relative to non-stress
was 95, 75 and 79% in 2004, 2005 and 2006, respectively. In all
the stress experiments, the drought-tolerant parents (IR55419-
04 and Safri 17) significantly out-yielded the susceptible
parents (IR64, Way Rarem, and Abhaya).