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

<strong>of</strong> two locations for two years. Except for <strong>plant</strong> <strong>height</strong>,
percent plumpness and days to heading, tnee! (error)
variance eomponents were very 1arge relative to their
respective C! (SenotVpic) and genotype by environment
interaction components, indicatíng one naJor drawback <strong>of</strong>
the design. emproyed may have been insufficient replication
and./or sampì"ing.
High herÍtabílíty estímates for most <strong>of</strong> the parameters
examined in this study were not unexpected since¡ one, the
rnaterials involved were in advanced generations i two, ample
geneti.c variation exlsted for. these traits¡ three, variance
eonponents were used to calculate the estimates; and. four,
the experiment was grown at more than one location for more
than one year. Àccording to the I!.terature, these eircum_
stances shourd combine to give rnaximum heritabirlty estirnates
(Grafius et aL., Lg56¡ Frey and Horner, L955t ana Rasmusson
and Glass, L96?).
ileritability estimates for <strong>plant</strong> <strong>height</strong>, kernel weight,
test weight, and percent pLumpness were consistent across
populations since these parameters can be measured accurately
and deviatíons between years or Ìocations were devi_ations
in nagnitude rather than ranking.
The following discusslon <strong>of</strong> genotJæe by environment
interactions, heritabilities and testing proced.ures is
grouped by eharacter or characters which behaved in a
sinílar fasl:ion.
P_lant <strong>height</strong>. Ehe very high heritability estimates
L75