Genetic Variation in Early Growth Characteristics of Two Populations of Wild Service Tree (Sorbus torminalis (L.) Crantz) and Their Interrelationship

This study was performed in order to compare two wild service tree populations (Sorbus torminalis (L.) Crantz) for their early growth and to find useful vegetative characteristics to be used in indirect selection of fast and tall growing trees of the species in the field. We used phenotypic and genotypic correlation coefficients estimated on data from 30 three-year old seedlings of each 40 randomly selected adult trees. Assuming genetic differences between the trees sampled, path analysis was performed on genotypic and phenotypic levels. Results showed that plus trees of one of the sites may be used for clonal seed orchard establishment. But the other site is suggested as a better site for breeding purposes with more effective Sorbus population. Collar diameter had the strongest positive direct effect and strongest correlation with plant height at the phenotypic level. In contrast, lateral branches showed very weak direct effect but relatively strong total indirect effect on plant height. Path analysis on the genotypic correlation coefficients detected negative indirect effect between the characters. Collar diameter could be regarded as a good predictor of plant height because of its strong direct and indirect phenotypic and genotypic correlations. The use of recommended selection criteria is discussed.