Variability of Siberian stone pine seed yield in introduction plantations in the Vologda region

Abstract

Selection of high-yielding samples of Siberian stone pine in artificial plantations created outside its habitat potentially improves the quality of work on its introduction. The study represents an assessment of the level of individual variability of Siberian stone pine by seed yield in the context of introduction (taking into account its variation by years of crop generation). Studies were conducted in the annually seeding Chagrinsky cedar grove located in the Gryazovetsky District of the Vologda Region. Sample trees were selected to observe the dynamics of seed formation in the plantation. Observations allowed us to conclude about the irregularity of yields from year to year and high variability in the volume of yields among individual trees. A significantly pronounced effect on the seed yield of Siberian stone pine is recorded both in terms of the year of cone generation and individual variability of the trees. Individual characteristics account for 41% of the total variation in yield, while the year of observation accounts for only 21%. Dependence on individual variability slightly decreases with the increasing duration of observations, which may be due to chronographic variability in the reproductive capacity of the trees. It was concluded that the selection of maternal producers for the creation of high-yielding plantations is advisable. At the same time, the increased observation period for the reproductive capacity of individual trees makes it possible to increase the efficiency of selection. To reduce the duration of observations, it was recommended to use the ratio of crown width to crown length as a correlative feature. Nevertheless, in some non-yielding years, the relationship between the yield and this feature may not be evident. For this purpose, the trees with the lowest value of this indicator should be selected as high-yielding ones.