Cultivar Overall mean
 (Metric ton/ha)
 14 4.267 a
 6 4.240 a
 9 4.214 a
 11 4.194 a
 7 4.186 a
 8 4.185 a
 13 4.026 a
 4 3.967 a
 5 3.928 a
 12 3.744 a
 2 3.623 a
 3 3.601 a
 1 3.587 a
 15 3.437 a
 10 2.357 b

For this case, Tukey's multiple range test shows that with
the exception of cultivar number 10, there are no
significant differences in yield. Cultivar 10 is
significantly lower in yield.
 Tukey's multiple range test for means is considered
by many researchers as too severe since differences have
to be large to be statistically significant (5% level).
For example, in this case there were differences of up to
20% in yield (.85 ton/ha) among the group where no
differences were detected. However, with this test there
is little risk of adjudging significant differences that
actually do not exist. There are a number of multiple
range tests for means and the most appropriate should
always be chosen. For a discussion on multiple range
tests for means refer to Chew (1977). Had two more sites
been included in this trial, a modified stability analysis
(Chapter VII) may have been useful for detecting superior
cultivars.
 Agronomic data serve to complement yield information.
In this case, when yield shows no significant differences,
the agronomic information is particularly important.
Table V-6 shows the mean values on the farm sites for days
to flower, ear height, and percentage of rotted ears.
Varieties are ordered according to yield.