Variability of Vegetative Progeny of Siberian Pine Plus Trees Certified for Stem or Seed Productivity

Abstract

Siberian pine (Pinus sibirica Du Tour) is a tree species differences by the diversity of valuable properties. Considering its value and reduction of its growing stock due to forest fires, death from silkworm and illegal logging, it is necessary to preserve and multiply the leading species, which were formed in vivo. The results of studying the Siberian pine in the conditions of the Southern Siberian mountainous forest site zone are presented. The research purpose is the study of variability of Siberian pine progeny on the trial plot. Plus trees certified in Novosibirsk region for seed and stem productivity were taken as parent trees. Plus trees had a height of 16.0-30.5 m and trunk diameter of 44-78 cm. The average number of cones on trees for a 10-year period before certification (1967-1977) was 203-470 pcs. Plus trees (35) certified in 1977 for stem (17 trees) and seed productivity (18 trees) were selected for the study. Their parameters were compared with the clone progeny at the scion's age of 29 years. The following biometric parameters of ramets of different clones were determined: height of stem, diameter and volume of stem and crown; length of needles; cones formation regardless of plus trees certification for stem or seed productivity. Clonal planting material was grown by grafting of Siberian pine to the 6-year-old seedlings in spring of 1989. The seedling' age was 8 years (scion - 6 years, rootstock - 2 years) when they were planted on a plantation. In subsequent years, variability of clone progeny parameters was observed. It was found that the biometric parameters and percentage of trees that formed cones had no significant differences in comparison of progeny of plus trees certified for both seed and stem productivity. The average number of cones in ramets of plus trees was significantly different by seed productivity. A large variability of parameters was observed among the clones and ramets in clones regardless of the purpose of selection in certification of parent trees. The heritability coefficient of parent trees was 40.7 % in height of clonal progeny, and 35.0 % in stem diameter. The individual ramets differ by growth intensity, seed and environmental productivity were selected. The obtained results can be used in the creation of the second generation clone plantations of increased genetic value in the conditions of the Southern Siberian mountainous forest site zone.