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

the effect <strong>of</strong> seeding rate on yield is affected by the
environment, in particular, the amount <strong>of</strong> water avail-able.
Pelton's (t969) results with lower seed.ing rates gíving
better yields when under moisture stress are evidence <strong>of</strong>
this. Kirby (19?O) reported no difference in total water
use for the growing season with barley seeded at various
rates i however, he did report that differences existed in
water use at different times <strong>of</strong> the season for the different
densities. He suggested that the higher density <strong>plant</strong>ings
used more v;ater earl-y in the growing period, and may then
suffer moisture stress during the grain filling stage. This
could present a problem in dry years or dry areas.
Ðay and Thompson (19?0), from work with winter barley,
reported that seeding date also had an effect on the optimum
seeding rate. They indicated that as the seeding date was
delayed the seeding rate should be increased.
Briggle and Vogel (1968) indicated that one <strong>of</strong> the
problems with the semi-dwarf wheats in the Pacific Northwest
was that they did not emerge well from deep <strong>plant</strong>ing,
apparently due to shorter coleoptile length.
A close positive correlation between culm length and
coleoptile length was reported by Allan et al. (1962),
sunderman (1964), Burleigh et al. (L964), and $than (L9?6).
in wheat studies, and by Takahashi (L946) in bartey experi-
ments .
JI