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

At all sites for both genotypes the 61.O cm" row
spaeing was inferior to the more narrow ones for yield.
There were no significant differences between the 1J.0
and 30.0 cn. widths at any site, although the serni_d$¡arf
did show a trend toh,ards higher yÍelds at narrower row
spacing under the adverse cond.itÍons at Carman.
fn general, yiel_d improvements were brought about by
increased nunbers <strong>of</strong> heads per unit area. fhis was accom_
panÍed by fewer kernels per head, and. where the compensa_
tion was not equal, a hígher yield resulted.
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Short coleoptiles have been associated wÍth decreased
<strong>plant</strong> <strong>height</strong> in wheat and with a reduction in the ability
and rate <strong>of</strong> emergence. fn the present.study a group <strong>of</strong>
standard <strong>height</strong> and semi-dwarf barley genotl4)es, chosen to
represent a wide range <strong>of</strong> yield levels, were checked for
coleoptile J.ength.
lhe results <strong>of</strong> this experinent indicated that the talf
barleys had longer coleoptÍles than the short statured. ones.
îhe evidence gathered suggested that the shorter coleoptiles
<strong>of</strong> the semi-dwarfs may hâve been the resurt <strong>of</strong> theÍr smar.l
kernel size.
For the genotypes studied the short coÌeoptiles <strong>of</strong> the
semi.-dwarfs did not affect thei.r enrergenee rate.
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