ISSN 10674136, Russian Journal of Ecology, 2009, Vol. 40, No. 5, pp. 368–373. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © N.F. Kuznetsova, 2009, published in Ekologiya, 2009, No. 5, pp. 390–395.
Active conversion to the system of seed growing in
forestry began in the Soviet Union in the late 1950s
(Efimov, 1997). Within its scope, an extensive network
of regional forest tree seed plantations (FSPs) was cre
ated in order to produce bulk quantities of highqual
ity seeds over long periods of time (
2000). From the standpoint of tree species biology, we
deal in FSPs with the formation of the gene pool of
daughter populations at the initial phase of their life
cycle, from initiation to seed maturation. Moreover,
the quality of seed production is the higher, the closer
the process of sexual reproduction of a given species in
a FSP approaches that occurring in nature, against the
background of variation in weather conditions during
consecutive growing seasons.
Free pollination as an essential component of sex
ual reproduction of the Scots pine (
includes selfpollination and crosspollination.
In general, selfpollination is regarded as an adverse
factor responsible for reduction in the numbers of
cones and seeds (Sarvas, 1962; Franklin, 1970). The
results of studies on inbreeding depression (Isakov,
1999; Isakov et al., 2000) show that selfpollination in
Scots pine results in intrapopulation differentiation
with respect to types of seed reproduction systems.
The distribution of trees into groups with different
types of these systems is determined genetically. The
nature of inbreeding depression in forms with con
trasting levels of selffertility has been studied at the
morphological, microscopic, and ultrastructural levels
(Kuznetsova and Isakov, 1987; Kuznetsova, 1996).
This study deals with the results of 12year experi
ment on monitoring the types of seed reproduction
systems in Scots pine in Voronezh oblast.
MATERIAL AND METHODS
Every year, 50 Scots pine trees of local origin (Vo
ronezh Forest Enterprise, Ramonskoe forestry; ran
dom sample) aged 35–40 years were used in experi
ments on selfpollination. All these trees (usually the
same from year to year) were phenotypically normal,
i.e., of good or average quality, condition, and height
, 2000) and showed consistent male and
female flowering in a series of growing seasons. In ana
lyzing genetic population structure, this sample served
as a model characterizing the Scots pine population of
the study region.
Controlled selfpollination was performed accord
ing to Kotelova (1956). Pollen from lower parts of the
crown was collected into tracing paper bags. Dates of
collection were adjusted to the period when micros
trobili took on yellow color. Isolation of macrostrobili
in paper bags began after their segregation (the erect
bud stage). Pollination was performed in the morning,
when female cones were most receptive (the open
cone stage), repeating the procedure twice. Isolating
bags were removed 7–10 days after pollination (the
closed cone stage).
To classify Scots pine trees with respect to the type
of seed reproduction into crosspollinating, selfpolli
nating, and transitional forms, Isakov (1999) devel
oped the system in which he divided the whole variety
of trees into five groups with respect to the level of self
Effect of Climatic Conditions on the Expression
of SelfFertility in Scots Pine
N. F. Kuznetsova
Research Institute of Forest Genetics and Breeding,
ul. Lomonosova 105, Voronezh, 394087 Russia;
Received October 12, 2007
—The results of 12year experiment on monitoring the types of Scots pine seed reproduction sys
tems in Voronezh oblast are generalized. Sample structure with respect to selffertility in optimal years is
characterized and its transformations in years with weather anomalies (cold, warm, moderately and severely
droughty) are described. It is shown that the contribution of selffertilization to annual seed production
increases proportionally to the severity of weather stress affecting the population.
: Scots pine, type of seed reproduction system, selffertility coefficient, selffertilization, climatic
conditions of the year.