Technology of thinning in Pinus sylvestris (L.) and Picea abies (L.) progeny tests

The thinning technology for progeny tests was developed. The researches are carried out in Pinus sylvestris and Picea abies progeny tests aged from 2 to 45 years in North-West Russia. The thinning technology would support the elite seed production (tested seeds) for the forest-forming species. The methodological basis is the modeling of influence of thinning performed by random and regular sampling methods with an intensity of 20 to 80 % on the results in progeny tests. Methods of plant removal during thinning in progeny tests are proposed. There methods are saving structure of initial progeny tests population and allow to perform comparative assessment of the growth rate for families in future. The influence removing methods and level of intensity such removing for part of the plants in progeny test on the experience results (significance of differences between families, the list of the best families, the rank stability of families and individual trees) are estimated. Families persistently maintain their average rank when using both regular and random methods of plant selection even with very high sampling intensity up to 80 % of their initial number. The method of regular sampling with selection based on actually preserved plants is recommended in progeny tests. Criteria for progeny test quality assessment and proposals the methodology for the estimation of the impact of thinning on the effectiveness of genotype testing have been developed. The results of the work can be used for the effective operation with the forest tree breeding objects. The introduction of the work results into silviculture practices will increase the efficiency of tree breeding works and ensure the transition to elite seed production for the main forest-forming species in Russian Federation.