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

educed kernel size and lack <strong>of</strong> yie.td stability, panticular]-y
unde:. conditions <strong>of</strong> stress" A procedure for o.,¡ercoming these
faults has been suggested above.
the semi-d¡varfs investigâted agronornically appeared to
require special attention to eurtural procedures to achieve
rnaximum performance, particularly when growing under un_
favourable environrnental conditions" Adequate weed control
was a necessity since the short statured. genotypes were poor
competitors. fhe seni-dwarfs Ín question seemed to have a
defínite minimun fertility requirement. Unfortunately, they
did not appear to re spond to high nitrogen levels to any
greater degree than did the tall cul-tivars.
îhe slow early growth <strong>of</strong> the sample <strong>of</strong> semi_dwarfs
investigated was particulârly disadvantageous under less
than ideal conditions. This slow growth was associ-ated with
the high spikes per unÍt area type, hence, â nore desirable
balance <strong>of</strong> yield cornponents might be expeeted to reduce this
problem. However, since spikes per unit area appeaned to
be the most influential <strong>of</strong> the yield cornponents, the lack <strong>of</strong>
competitive ability <strong>of</strong> hÍgh yielding semi-dwarfs may be dif_
ficult to overcome. The tillering cornponent is irnportant in
providing a neans <strong>of</strong> response to more ideal environnents,
particularLy to optimum r-eve1s <strong>of</strong> moisture and fertiLizer.
Às previously stated, the greatest advantage <strong>of</strong> the
semi-dwarfs would bê in the areas best suíted to barley
production" In Western Canada these are the regions wbere
straw strength is inportant, characterized by a con_
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