Agriculture Reference
In-Depth Information
HTC value for regeneration increases in the years of precipitation defi cit. Owing
to the fact that from May till the end of August of 2009 average monthly air tempera-
ture was 0.4-4.3°С lower, and in turn evaporation was lower than in the same period
of abundant precipitation in the summer of 2010, contingency of regeneration abil-
ity with HTC was higher in 2009. Precipitation amount and air temperature in 2010
exceeded the indicators in the year of 2009, which affected considerable increase of
correlation coeffi cients between indices of regeneration ability of pear cultivars and
average monthly air temperature.
In 2012, the experiment continued and another pear species
Pyrus salicifolia
Pall
was added/involved. Meteorological conditions of pear vegetative season in 2012
were characterized by increased average monthly air temperature by 1.8-4.4°С, as
compared with average many-year indices and monthly precipitation defi cit (except
for June), and accordingly by very low HTC. Under these conditions, contingency of
regeneration ability of light-loving xerophyte and mesoterm
P. salicifolia
with HTC
was much higher than that of long-naturalized
P. communis
(Table 15.3).
TABLE 15.3
Correlation coefficients between the indices of regeneration ability of pear
species and precipitation amount, temperature and HTC when notchings are made
Species
Р (мм)
Т (°С)
НТC
Pyrus communis
L.
0.14
0.75
0.10
Pyrus salicifolia
Pall.
0.13
0.66
0.54
Note: Р
> 0.95
Correlation coeffi cients between the indices of regeneration ability of both pear
species and precipitation amount were almost equally insignifi cant, but contingency
of regeneration ability with average air temperature was rather high,
P. communis
predominating. It is worth mentioning that during the whole season 2012 regeneration
ability of
P. communis
was higher that that of
P. salicifolia
(Figure 15.4)
.
Maximal
index of regeneration coeffi cient of
P. communis
amounted to 10.12 urc in the variant
when notching was made on August 20, whereas the best indicator of
P. salicifolia
hardly reached 2.45 urc (the notching was made on July 11). All this gives every
ground to assume that the indicator of regeneration ability can prove the level of eco-
logical adaptation of the genotypes studied.
With the exception of the third decade of March (the beginning of the experiment)
and the third decade of September (the fast damping of regeneration rates), when the
regenerative potential of
P. salicifolia
was slightly higher than
P. communis
, the curves
of a seasonal variation of the both species for the
year 2012
were quite similar.
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