Effects of reduced plant height on breeding requirements and ...

in these populatíons two locations for tv,ro years were
sufficient. Less genetic variance and a strons Af , Save
rise to lower herítability in e-?O-3, fhe6Êy again reflect_
ed the effects <strong>of</strong> the stress conditions <strong>of</strong> Jg?4 on C_?O_3,
Generall-y l-ow levels <strong>of</strong> o! ínaicated the replication used
was suffic ient.
. Heritabillty
was lower in C-?O-l and C-?0-3 than in C-?O_Z, ín
which it was very high. This difference reflected a large
,
ff,y in both C-?0-1 and C-?O-3, probabty a result <strong>of</strong> response
to environmêntar- stress Ín 1924. rlhe more íntense effects
<strong>of</strong> drought on C-?0-3 were further indicated by the larger
)
S component for that population.
The heritabiLity <strong>of</strong> days in post-anthesis will be
governed by the effects <strong>of</strong> the environment on both days to
heading and maturity, since these components were used to
caLculate this pararneter.
over the three populations studied, the general lack
D
<strong>of</strong> C[" significance comblned with the generally sígnificant
a
levels <strong>of</strong>6!y, suggested that testing for rîore than one year
was necessary to evaluate days to naturity and days in post_
anthesÍs, while the need for more than one locatíon was
doubtful. More replication should be used when the cal_cu_
lation <strong>of</strong> days ín post-anthesís is to be carried out since
it's{ can be ínflated by errors in the esti.mation <strong>of</strong> both
days to heading and maturity.
Kernel-s per spike. This trait was highly heritable and
L78