Abstract
Tree health and growth rate must both be considered in Scots pine breeding for harsh areas such as northern Sweden. Univariate (UV) and multivariate (MV) multi-environment trial (MET) analyses of tree vitality (a measure of tree health) and height (a measure of growth rate) were conducted for four series of open-pollinated Scots pine progeny trials (20 trials total), to evaluate age trends, patterns, and drivers of genotype-by-environment interaction (G × E). The lowest standard errors were obtained for the MV MET analyses, indicating that MV analyses are preferable to UV analyses. By incorporating factor-analytic structures, the most complex data sets could be handled, suggesting that factor-analytic analyses are preferred for evaluation of forest progeny trials. We detected strong patterns of G × E for both tree vitality and height, and the driver of G × E was found mainly to be differences in degree day temperature sum, such that G × E was higher between trials with more contrasting temperature sums. The genetic correlations, between vitality and height within sites, were generally positive and were driven by the harshness of the trial; mild trials had lower genetic correlations than did harsh trials. The sign of the across-site genetic correlations between vitality and height changed from positive to negative in some cases, as the differences between the temperature sum of the trials increased. These findings support the hypothesis that tree height assessed in harsh environments with low survival is likely to reflect health and survival ability to a greater extent than growth capacity.
Highlights
IntroductionGrand Royal Est, Shefford, QC J2M 1R5, Canada
Mortality in artificially regenerated Scots pine (Pinus sylvestris L.) forests is seldom caused by a single event but is usually the result of damage accumulated over several years (Eiche 1966; Stefansson and Sinko 1967)
The objectives of this study were the following: (1) compare the utility of UV and MV multi-environment trial (MET) analyses; (2) estimate genetic correlations between tree vitality and tree height, at different ages, in different environmental conditions, based on the robust method; (3) test whether there is a dynamic relationship between site harshness and genetic correlations, and whether G × E is related to temperature heterogeneity among sites; and (4) estimate additive and environmental coefficients of variation for vitality and height at two ages, in four unrelated series of five open-pollinated (OP) Scots pine progeny trials (20 trials in total), in northern Sweden
Summary
Grand Royal Est, Shefford, QC J2M 1R5, Canada In harsh climates, such as in northern Sweden, both individual tree vitality (a measure of survival ability, over the range from healthy to dead) and growth impact forest productivity (Ruotsalainen and Persson 2013). They are important traits in tree breeding programs to maximize stand volume production. The accumulated injuries are primarily related to the harsh climate, reducing the plant’s capacity to grow and develop during subsequent growing seasons This may result in further damage (climatic-, fungal-, or insect-related), increased mortality and suppressed the growth of surviving-but-damaged individuals. In Scots pine regeneration in cold areas, two of the most common fungi for which additive genetic variation in resistance has been reported are Gremmeniella abietina (Lagerb.) and Phacidium infestans L. (Persson et al 2010)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
