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Genotypic tradeoffs along environmental gradients help maintain diversity in functional traits in the wild and limit the range of suitable environments for each genotype in tree breeding programmes. Little is still known of the capacity of abiotic and biotic soil variation to generate marked shifts in genotypic performance ranks. We examined the potential of belowground soil factors to bring about genotype × environment interactions in a tree species by combining data from extant field trials and a new seedling-based progeny experiment. We first analysed genotypic growth patterns of Norway spruce (Picea abies) at two field trial locations, a native forest site and a former agricultural field, that exhibited biotic and abiotic soil variation. While we found significant genotype × location interactions in growth, we also observed positive between-location genotypic correlations, indicating similar genotypic rank orders across divergent soil types. Contributing to the genotype × environment interactions, differences in age at the time of growth measurements may explain why genetic variances nevertheless differed between the locations. The subsequent progeny experiment with soil and seeds collected at the trial locations enabled controlled treatments in a growth chamber that tested the capacity of between-location soil variation to induce genotype × environment interactions in seedling traits. The progeny experiment revealed that the soil treatment had major effects on averages in all 14 shoot and root functional traits, with four groups of correlated traits (e.g., estimates of shoot and root system size) identified by a principal component analysis. Seed collection location affected only few traits, and the more southern agricultural field trial yielded slightly larger seedlings with delayed phenology. Yet, despite significant genetic variation, no seedling trait manifested genotype × soil treatment interactions, which may be due to the soil treatments not mirroring spatial heterogeneity of the soils at the trial locations, or to our limited subsample of ten genotypes in the progeny experiment. Taken together, our results on adult trees and seedlings indicate that overall tree growth is impacted by variation in belowground environmental factors, but further research with more comprehensive sampling is needed to determine whether they have potential to generate location-specific patterns of genotypic performance in economically valuable tree species. • Biotic and abiotic soil variation may cause genotypic tradeoffs in Norway spruce. • We combined observations from two field trials and a new progeny experiment. • We found tradeoffs in growth in adult trees, but not in seedling functional traits. • Genetic and soil variation had independent effects on functional trait variation. [ABSTRACT FROM AUTHOR]

Plants are assumed to have a trade-off between growth and resistance. This trade-off has been demonstrated in herbaceous plants, but the information on woody plants is conflicting. In contrast to simple annual plant–herbivore systems, trees face highly variable herbivory. In this note, we measured clonal variation in the growth of Betula pendula and in its resistance to nine major herbivore species belonging to five different feeding guilds. There were significant differences in both the growth and the resistance of clones to all the herbivores studied. However, we found no negative correlation between growth and resistance. No clone was generally resistant or susceptible to most of the herbivores. This suggests that, if there is an ultimate trade-off in resource allocation of B. pendula between growth and resistance, it is masked by other factors, for example, by several opposite abiotic and biotic selection pressures. [Copyright &y& Elsevier]

• Thekopsora areolata incidence varied greatly among years in Finnish Norway spruce seed orchards. • Amount of rainfall in May-June explained the annual T. areolata incidences on Prunus padus. • Rainfall, temperature, time and their interactions were significant variables in a disease model. • To control T. areolata the number of overwintering diseased Prunus leaves should be minimized. • Control of C. pirolata should concentrate on Pyrola in early May and on P. abies in late May. Cone rusts Thekopsora areolata and Chrysomyxa pirolata are widely distributed in northern hemisphere. In Fennoscandia, these rusts cause severe damage and great economical losses especially in seed orchards specialized to produce high quality seeds. The aim of this study was to investigate sporulation of cone rusts and factors affecting epidemics to develop new control practices against these rusts. Natural sporulation of T. areolata was investigated in Finnish Norway spruce seed orchards on Prunus padus and the effect of environmental variables on rust sporulation in 2018–19. A sample of Prunus leaves was collected from which the coverage and number of T. areolata pustules were estimated. The frequency of cones with cone rusts, T. areolata, Chrysomyxa pirolata and C. ledi, was also estimated in Picea abies cones and the sporulation of C. pirolata on Pyrola sp. leaves in the seed orchards. The T. areolata incidence on Prunus was modelled with temperature sum, rainfall, seed orchard and time of estimation. The T. areolata disease incidence was low (<30%) in seed orchards in 2018, but it exceeded 100% in 2019. T. areolata pustules covered less than 10% of the leaves in 2018 and 10–40% in 2019. An ascomycete, Phloeosporella padi, was common in all Prunus leaves in 2018–19. Low rainfall in May-June explained the low disease rate on Prunus in 2018, while high rainfall explained the high disease rate in May-June in 2019. Cumulative rainfall, temperature sum, time and their interactions were all significant variables in a disease model explaining the disease incidence, while seed orchard was a non-significant variable. Cone rust frequency was low in P. abies cones in the seed orchards in 2019. Telia with basidia of C. pirolata were rare in May-June on Pyrola due to low rainfall in 2018, but frequent due to high rainfall in 2019. Rust control of T. areolata is recommended to concentrate on Prunus to reduce the number of overwintering diseased leaves in the seed orchards. Old infected cones should be removed from seed orchards to reduce aeciospore dissemination to Prunus in May-June. Control of C. pirolata is recommended to concentrate on Pyrola in early May. [ABSTRACT FROM AUTHOR]