H estimates for a selection unit co

H estimates for a selection unit consisting of mean line yield
from single-row plots in two replicated trials under upland
stress ranged from 0.45 to 0.66; in the upland non-stress trials,
the range was 0.47–0.78 (Table 3). The range was 0.48–0.67 in
the lowland stress trials and 0.41–0.68 in the lowland non-stress
trials. In some cases, H was higher for non-stress trials;
however, in two cases in upland (IR55419-04/Way Rarem in
2006, IR55419-04/IR64 in 2004) and in all four cases in
lowland (IR55419-04/IR64 in 2006, Abhaya/Safri 17 in 2004,
2005 and 2006), H was greater under drought-stress than under
non-stress conditions. The relatively higher but similar H
estimates for grain yield under stress and non-stress situations
in all the screens under lowland indicates that selection for
grain yield under reproductive stage lowland drought stress in
rice can be carried with the same level of precision as that
achieved in non-stress. The similar H under upland situation