Limitations at the Limit? Diminishing of Genetic Effects in Norway Spruce Provenance Trials

Abstract

Provenance trials are used to study the effects of tree origin on climate-growth relationships. Thereby, they potentially identify provenances which appear more resilient to anticipated climate change. However, when studying between provenance variability in growth behavior it becomes important to address potential effects related to site marginality in the context of provenance trials. In our study we focus on provenance-specific climate sensitivity manifested under marginal growth conditions. We hypothesized that the provenance effects are masked if trials are located at marginal environmental conditions of the natural species distribution. Under this framework, we investigate 10 Norway spruce provenances growing at two contrasting locations, i.e., a relatively drought-prone site in western Poland (at the climatic margin of Norway spruce’s natural distribution) and a mild and moist site in north-eastern Poland (within its natural range). Combining principal component analysis with climate-growth relationships, we found distinguishable growth patterns and climate correlations among provenances. That is, at the mild and moist north-eastern site, we observed provenance-specific growth patterns and thus a varying drought susceptibility. In contrast, at the dryer western site, provenance-specific growth patterns were less pronounced and all provenances expressed a common and strong sensitivity to drought. Our results indicate that the genetic specificity of growth reactions diminishes toward the distributional margins of a given species. We conclude that the climate conditions at the margins of a species’ distribution are constraining tree growth independently of tree origin. Because of this, the marginality of a site has to be considered when evaluating climate sensitivity of provenances within trials. As a consequence, the yet different responses of provenances to adverse growing conditions may synchronize under more extreme conditions in course of the anticipated climate change.

Genotype-by-environment interaction in coast redwood outside natural distribution - search for environmental cues

“…We hypothesize that it was due to the low productivity at the site, which we discuss further below. Similar to our study, the missing genetic component was found for drought tolerance in Norway spruce when tested outside the range of species natural distribution [42]. Some GxE interactions at the genotype-within-population level were found when broad-sense genetic correlations between sites decreased slightly below 0.7 in most cases, except Awaho -Taranaki and Awaho -Ngapuke farms.…”

“…Larger sized estimates of genetic components/heritability can generally be reached under optimal growing conditions, where the expression of underlying genetics is also optimal or close to optimal. Any sub-optimal conditions such as environmental stress can result in the reduction and potential disappearance of the expression of the underlying genetic potential and the reduction in the estimated genetic component [42,58]. Hence, it is likely that the conditions at the Taupō site are limiting for the growth of planted coast redwood in New Zealand.…”

The Effect of Insect Defoliations and Seed Production on the Dynamics of Radial Growth Synchrony among Scots Pine Pinus sylvestris L. Provenances

“…Provenance experiments originally established to assess inter-species variability in productivity and growth performance have recently gained importance as a valuable source of information for provenance-specific climate-adaptation potential [5,6]. Climate-dependent radial growth variation reflects the sensitivity of species and provenances to climate anomalies; however, marginal growth conditions may diminish differences among provenances in climate-growth responses and thereby hamper the detection of provenance-specific, climate-related adaptive responses [7]. The cumulative effect of adverse climatic conditions and biotic factors such as the above average seed production and insect outbreaks may have a negative effect on tree-ring width and consequently weaken climate-growth relationships [8][9][10].…”

“…The growth synchrony among spatially separated provenances observed in natural populations [11] is a relatively common phenomenon in common garden experiments (e.g., [7]). Undoubtedly, spatial synchrony, caused by regionally correlated climatic conditions, has implications for natural population dynamics [12]; however, little is known about how to interpret this phenomenon in provenance trial conditions.…”

Intra-annual stem size variations converge across marginal populations of European beech

“…Due to the climate-transfer-related constrains in studying provenance adaptability on common garden experiments, resulting from possible maladaptation of populations or diminishing effect of marginal site conditions (Klisz et al 2018(Klisz et al , 2019a, we applied multi-dimensional analysis of bioclimatic parameters. Two-object clusters (provenances 453 and 455), located closest to the provenance trial, would suggest a better adaptation of these two populations to the growing conditions than the provenances 390 and 451, which are climatically more distant.…”