Differentiation of Plus Trees of Scots Pine by Xylem Conditions

An essential stage in the establishment of seed orchards is the formation of an optimal composition, avoiding inbreeding depression in the produced seed material, which develops as a result of crossbreeding between closely related plus trees. The negative effect can be reduced by ensuring the genetic heterogeneity of the seeds. The purpose of this study is to give a relative evaluation of the plus trees of Scots pine (Pinus sylvestris L.) as one of the most economically significant tree species on the European continent according to their physiological conditions. The formation and lignification of the xylem of the plus trees were investigated in the Nizhny Novgorod region of Russia. A histochemical examination was performed using the reaction of phloroglucinol to lignin. Phenotypic differences in the physiological conditions of plus trees appeared on a uniform ecological background that indicates their genotypic determinism. This fact was confirmed by ANOVA. The share of the influence of differences between the proper plus trees was between 25.16±8.91 % and 53.98±5.48 %. According to the results of the factor and cluster analysis, the association of plus trees was generated by the similarity of the multidimensional estimates of the xylem conditions. The objects that were statistically most distant from the others were determined. The hereditary conditionality of the identified differences among plus trees allows us to consider their grouping into clusters as genotypically determined. This information provides a reasonable approach to the formation of an assortment of Scots pine clonal seed orchards. For citation: Besschetnova N.N., Besschetnov V.P., Babich N.A., Bryntsev V.A. Differentiation of Plus Trees of Scots Pine by Xylem Conditions. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 4, pp. 9–25. (In Russ.). https://doi.org/10.37482/0536-1036-2023-4-9-25