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

signlficant, the correl_ations were generally small, result_
ing in small r2 values. Further¡nore, the relationships were
strongest in C-IO-J, where all the genotypes were shorter
than standard <strong>height</strong>, indieating thât the very short material
was lacking in these traits but that moderate <strong>height</strong> reduc_
tion did not adversely affect important agronomic characteristics.
The absence <strong>of</strong> any significant correlatLons <strong>of</strong> <strong>plant</strong>
<strong>height</strong> with kerneLs per spike may have resul"ted from the
faet that selection for large spikes was emphasl_zed in
developing the semi-dwarf parent used (Rasmusson, L)IJ),
Nevertheless, a rarge amount <strong>of</strong> variatíon existed for this
parameter, and the error in determíning its vaLues rnay in
part account for the lack <strong>of</strong> relationship.
Reduced <strong>plant</strong> <strong>height</strong> did effectively reduce lodging.
This positive eorrelatÌ.on may be partially due to the fact
that the lodging encountered was the late season type caused
by the straw not being strong enough to support the heavier
spikes <strong>of</strong> the higher yieldlng lines. The positive <strong>height</strong>
to yield and yield to ).odging relationships may have con_
tributed to the <strong>height</strong> to lodging association. The relati_on_
ship was stronger in C-ZO-1 and C-20-3r both <strong>of</strong> which had
more very short types than t-?O-2.
According to the correlations, the shorter material in
C-7O-1 and C-20-j headed later. fhe <strong>height</strong> to heading
assocíation was also negative, but non-signifieant, ín
ë-7A-2. The lack <strong>of</strong> significance may have been due to the
18s