Genetic Variation Among and Within Populations in Swedish Species of Sorbus aucuparia L. and Prunus padus L. Assessed in a Nursery Trial

Abstract

Abstract Seedlings originating from open-pollinated offspring of six and four populations of Prunus padus and Sorbus aucuparia, respectively, were studied with respect to phenology and growth traits for 3-4 years in a nursery. There were no replications at the population levels since the experiments should be converted to seedling seed orchards. Therefore, a special statistical model for analysis of the population effect was developed making use of neighbour performances. This model was also used for derivation of heritabilities. The heritabilities for phenology traits were in many cases high in P. padus, > 0.40, while they varied in the range 0.07-0.62 in S. aucuparia. The population effect was significant for all growth rhythm traits in P. padus and for a majority of traits in S. aucuparia. In both species the heritability for height decreased over time. Only bud flushing in P. padus indicated a relationship with population latitudinal origin in some cases. The genetic correlations between bud flushing different years were relatively strong in both species while the corresponding correlations for leaf colouring were moderate in P. padus and weak in S. aucuparia. In conclusion, the observed structure suggests that the pattern of seed dispersal may have an influence on the among- and within-population variation.