Population genetics meets dendrochronology: joint approaches to explore growth and reproductive dynamics in forest tree species

Camilla Avanzi 
IBBR - UOS Sesto Fiorentino (FI) - Italy

April 28, 2021 (11:30-12:30)
Webinar Link: https://global.gotomeeting.com/join/877047565

Abstract: Reproductive dynamics have a major role for the maintenance, demography and adaptation of forest tree populations. Understanding which individuals have a higher reproductive success, and why, is therefore crucial to predict the evolutionary trajectory of tree populations, especially in fragmented landscapes and/or in stressful environmental conditions. The development of parentage analysis methods and polymorphic genetic markers has allowed plant biologists to get reliable estimates of lifetime reproductive success. Nonetheless, the determinants of reproductive success, as well as their interactions, are still largely under-documented. In particular, the relationship between growth and reproduction has been rarely assessed, except for using rough measures of diameter to be regressed against reproductive success. Such relationship is a promising aspect to be investigated more in details, mainly because of the tight trade-offs existing between growth and reproduction, and the major consequences they both have on evolutionary dynamics. In this seminar, I will illustrate how we proposed to distil the myriad of information embedded in tree-ring data into a set of tree-ring based phenotypic traits to be investigated as potential drivers of reproductive success in forest trees. By using a cross-disciplinary approach that combines parentage analysis and a thorough dendrophenotypic characterisation of putative parents, we assessed sex-specific relationships between such dendrophenotypic traits (i.e., age, growth rate and parameters describing sensitivity to climate and to extreme climatic events) and reproductive success in Norway spruce (Picea abies), one of the most relevant European conifer. We reconstructed parent-offspring relationships between 604 seedlings and 518 adult trees sampled within five populations from southern and central Europe. We found that individual female and male reproductive success was positively associated with tree growth rate and age. Female reproductive success was also positively influenced by the correlation between growth and the mean temperature of the previous vegetative season. Overall, our results showed that Norway spruce individuals with the highest fitness are those who are able to keep high-growth rates despite potential growth limitations caused by reproductive costs and climatic limiting conditions. Identifying such functional links between individual ecophysiological behaviours and their evolutionary gain would increase our understanding on how natural selection shapes the genetic composition of forest tree populations over time

Author's Info: https://ibbr.cnr.it/ibbr/info/people/camilla-avanzi

Link to video: https://youtu.be/NVncHymLas0