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tion. In 2007, when notchings were made at the beginning of the third decade of May,
the maximal/highest index of regeneration coeffi cient was recorded—5.60 urc, and
in 2008 and 2009—5.39 and 5.60 urc, respectively. When notchings were made in
the fi rst and second decades of June, the indices of regeneration coeffi cient decreased
slightly in 2007-2009, and at the beginning of the third decade of June the peak of
the second regeneration coeffi cient rise was recorded. In the fi rst decade of July, the
indices of regeneration coeffi cient decreased gradually by 1.37-1.85 urc.
In 2010, the regeneration coeffi cient increased bit-by-bit, having reached its maxi-
mum 12.79 urc at the end of the fi rst decade of July. When notchings were made in
the second decade of July in 2007 and 2009, the regeneration coeffi cient rise was
observed, its indices being 4.86 and 4.35 urc, correspondingly. In 2008 a similar re-
generation coeffi cient rise did not take place in the same period. In 2010, in the sec-
ond-third decades of July, the indices of regeneration coeffi cient decreased almost by
8 urc, and in the fi rst decade of August they increased by 10.29 urc. When notchings
were made in subsequent terms, regeneration coeffi cients gradually decreased in all
years of investigation and they were zero-proximity at the end of September or at the
beginning of October.
The tendency of higher dependence of regeneration coeffi cient on temperature
fl uctuation than on precipitation amount was identifi ed in earlier researches/experi-
ments with the representatives of
Corylus
L. [10] and
Malus
Mill [14]. This tendency
was confi rmed in the trials with the above-mentioned pear cultivars in 2009 and 2010.
Correlation coeffi cients of the indices of regeneration coeffi cient, received in 2009
with precipitation amount (Р, мм), air temperature (Т, С), and hydrothermal potential
(НТC), prove that higher contingency of regeneration coeffi cient with HTC and slight
connection with precipitation amount when notchings are made (Table 15.2).
Taking into consideration the fact that in warm months when precipitation supply/
support is very important, and the sums of effective temperatures decreased by one
order, are nearly equal with evaporation amount, we can assume that HTC denomina-
tion in fact characterizes evaporation, and the relationship of precipitation amount and
evaporation is the indicator of moisture support of the area in a vegetative season [17].
TABLE 15.2
Correlation coefficient between indices of pear regeneration ability and
precipitation amount, temperature and HTC when notchings are made
2009
2010
Cultivar
Р (мм) Т (°С) НТC Р (мм) Т °С) НТC
Bere Desiatova
0.14
0.51
0.49
0.35
0.82
0.50
Umans'ka iuvileina
0.26
0.51
0.73
0.46
0.73
0.38
Kniahynia Ol'ha
0.30
0.44
0.56
0.36
0.87
0.22
Sofiia
0.19
0.39
0.53
0.30
0.79
0.29
Note: Р
> 0.95
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