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

Genotype s differed sågnificantly only at Carman, where
Bonanza averaged approximate ly six more kernels per spike
than the semi-dwarf (fable 61). This behaviouro different
fron that at the other sites, as well as the laek <strong>of</strong> inter*
actions at Carman, can be attributed to the inabiJ.ity <strong>of</strong>
the semi-dwarf to cope with the high l-evels <strong>of</strong> stress at
this site.
Significant reductions in kernels per spike occurred
at all sites as seeding rates irìcreased (Table 61). A
sínílar result was previously reported by Guitard et at.
( 1961).
Row spac ing did not significantly affect kerneJ-s/spike
in this study (fable 6o).
Sígnificant genotype by seedÍng rate and genotype by
row spacing interactions occurred at Sanford (faefe 6O¡.
The first <strong>of</strong> these oceurred due to the tall genotype r s
kernel nurcber per spike declining significantly with each
seeding rate increase, while the seni-dwarf.s declined only
with the first increment, and did not drop as rnuch (Table
61). îhe second interaction occurred because the sem,i.-
Cwarf showed fewer kernels per spike as row spacing narrowed.,
while the ta]1 genotype showed the reverse (fable 61).
A second order genotype by seeding rate by row spacing
interaction occurred at ïfinnipeg (fable 60). The semi-dwarf
had more kernels per spike at the narrowest row spacing and
lowest seeding rate, and as the seeding rate increased at
that spacing the tall genotype beca¡ne superior in kernels
L44