Averaged across the five genotypes, there was no sig-nificant difference in grain yield between indica inbreds
and hybrids in the WS (Table 2). The NPTs had signifi-cantly lower grain yield than the hybrids in the 2003 WS
and than both indica inbreds and hybrids in the 2004 WS.
The difference in aboveground total biomass at physio-logical maturity among the three groups of rice cultivars
was not consistent between the 2003 WS and the 2004
WS (Table 2); however, hybrids generally had the lowest
biomass among the three groups of rice cultivars in the
WS. Hybrids showed 10 to 12% higher harvest index than
indica inbreds and NPTs, while there was no difference
in harvest index between indica inbreds and NPTs in the
WS (Table 2). Among the three groups of rice cultivars,
hybrids had the shortest growth duration in the WS.