SUBSTANTIATION OF AN ENHANCED TECHNOLOGY FOR CREATING SCOTS PINE GRAFT SEED ORCHARDS

Abstract

Establishment of coniferous seed orchards using grafts from plus trees is a promising development alley for forest seed breeding. To augment the harvesting of genetically enhanced forest plant seeds and to obtain high-quality planting stock from them, it is necessary to modify the approaches to forest seed breeding in line with the “Russian Forest Sector Development Strategy 2030”. The study seeking to improve the technology of creating 1st generation Scots pine graft seed orchards with group planting layout produced data leading to certain conclusions. The best conditions for cross-pollination are achieved by planting three seedlings grafted with scions of different clones in one plot. Spacing between seedlings in the plot should be up to 0.5 m. Tree topping, which does not provide a noticeable increase in the yield, is excluded from the operations chart as a costly method and replaced by thinning when the tree becomes higher than 8 meters. Cones are harvested after the plot is thinned leaving the number of trees adequate for producing the required seed harvest volume. The service life of the plantation is thereby increased to 35 years or more versus the planned 25 years, and merchantable timber can be obtained in the process of operating the orchard. Planting of three seedlings in one plot improves the orchard’s survival in cases of damage by large ungulates (moose). Also, planting of rows of non-grafted seedlings grown from selected seeds in the orchard’s margins contributes to its preservation