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

have increased the precision <strong>of</strong> the estimates.
Degree qf lodEinE. îhe data indicated that the design,
two replicates and three station-years, was aalequate for
ì-odging estimation, gíving relatively hígh heritability and
no significant genotype by environment i.nteractions. However,
this nay be reLated to the nature <strong>of</strong> the material_s
lnvo1ved, since <strong>plant</strong> heÍght was a major variable and
dl"ffer.ences ln lodging were closely assocÍatett wíth <strong>height</strong>
differences. It would therefore be unwise to assume that
the conclusions derived from these data would be widely
applícable. Àgain the6j was larger than the respective
6ã ín al"1 cases sugge sting a more precise neasurement
and/or more replication was needed.
Test weLght and percent plumpne ss. Although these
traits were moderately to highLy her5.tabJ_e, the results
suggested that testing for them required more than one year
and locatÍon. SignificantAfr., tor test weight ín Ç_?A_Z
and for percent plumpness ln all crosses, along with the
2D
6ãf, leveLs
".dorãr,V
for plumpness, <strong>reduced</strong> heritabÍlities
and Íncreased the respective standard errors. The inabirity
<strong>of</strong> C-7O-3 to eope with the drought and heat stress <strong>of</strong> I)14,
relative to C-20-1 and. C-IO-Z, in part accourits for the
a
greater 6ifr" for that populatíon.
Days to headinE. The signÍficance <strong>of</strong> the various geno_
type by envíronment interaction components indicated a need
for testing for this trait at more than one location and year,
despÍte the high heritability estimates in C_/O_t and. C_IO_Z;
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