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ment, keeping alive, and research of world collection of wheat, aegilops and triticale)
[14].
Biological stability characterizes the reaction of plant organism during its onto-
genesis to combined effect of environmental factors [15]. The amount of plants, which
passed all phonological phases until ripeness, is the criteria of stability.
13.3 RESULTS AND DISCUSSION
The years of study differed by moisture supply and temperature regime both among
them, as well as from long-term means. Thus, vegetation seasons 2007 and 2008 were
wet and warm; in 2009, 2010, and 2011 water deficit was observed at the background
of elevated air temperature (in 2010 and 2011).
The temperature of December-February 2007-2008 exceeded long-term mean
by 3.0-3.5°С. Precipitation total in 2007 exceeded normal (115%); and in 2008, it
consisted 68.5 percent of normal. Winters 2009, 2010, and 2011 were cold; but in
2009-2010, it was a lot of snow and in winter 2011 it was only little snow.
In these conditions, the survival probability of plants of the studied winter wheat
samples varied considerably (from 10.5 to 100.0%); overall mean for all years was
53.0 percent (Table 13.1). High values of the coeffi cient of variation (32.09-41.55%)
indicate high variability of the character.
TABLE 13.1
Variability of survival probability of plants of the winter wheat samples during
years differing by meteorological conditions
Year of study
Mean of samples (%)
CV (%)
Min
Max
2007
41.55
13.0
100.0
48.4 ± 2.39
2008
32.09
13.1
100.0
75.5 ± 2.29*
2009
39.48
11.6
100.0
55.1 ± 2.31
2010
37.76
16.2
100.0
49.7 ± 1.76
2011
35.8 ± 1.34*
38.02
10.5
69.4
5-years mean
53.0 ± 1.09
37.78
12.5
82.6
Note: statistically significant differences (Р 0.05) with ·—2011; *—5-years mean for all
samples; and CV, %—coefficient of variation.
The lowest probability of plant survival was observed 2011, which can be related
with insuffi cient amount of precipitation in December-February (41.5% of normal).
The maximum probability of survival (75.5%) was observed in the wettest year from
the whole period—in 2008, when annual precipitation total was 539.3 mm compared
with long-term average of 382.9 mm (141.0% of normal). Plant water supply could
be considered as suffi cient, as a high precipitation amount was in February-March,
exceeding long-term average by 76.0 percent; and in May during growth of plants, it
was optimal (102.0% of normal).
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