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

The associatíon between root growth rate and <strong>plant</strong>
<strong>height</strong> also supported the contention that the se¡ni_dwarfs
had sì ower devel_oping root systems, However, as u/as the
ease in Experiment IV with coleoptile length, the strong
posítive associations <strong>of</strong> the root growth and size paraneters
and <strong>plant</strong> <strong>height</strong> with kernel weight and plumpne ss suggested
onee again that the relationship may be ind.irect, caused by
the tendency <strong>of</strong> the semi-dwarfs in question to have smarler
kernels, giving rise to less vigorous seed.lings.
tautl-on should be exercised in drawing conclusions
from these results due to the large errors encountered in
measuring these parameters under the condÍtions <strong>of</strong> the
experiment. ft should also be noted that the root systems
were restricted in growth by pot size¡ hence the extrapola_
tion <strong>of</strong> these data to field conditions may not be posslble.
Exneriment Vf¡ Seeding Ðepth and EmerEence Ftudv
Accornpanying the suspected coleoptile length problem <strong>of</strong>
semi-dwarfs, researchers have voiced fears that these geno_
types wi1L be unable to energe from deep <strong>plant</strong>ing or that
they wilL not energe quickly.
lhe results <strong>of</strong> this study indicated that no differences
existed between the tal1s and semi-dwarfs for emergence
ablLity or rate. AI1 genotypes vrere eapabl_e <strong>of</strong> energing
fron 7"6 cm. and al1 had equal difficulty from 1O.2 cm. ln
fact, c703032 aîð, 6zoJo[, both semi-dwarfs, were superior
to the other genotypes in emergence. These results suggest
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