Long-term progression of inbreeding depression in a Mediterranean ornithophilous shrub

Abstract

The ornithophilous species Anagyris foetida L. is a Mediterranean shrub with highly fragmented populations and a mixed mating system. In a previous study, we analyzed the first 3 years of the life cycle of two progenies (selfed and outcrossed) grown from seed obtained by hand pollination and planted in an experimental garden in 2005. In that study, we found that inbreeding depression (ID) was manifested both reproductively and vegetatively throughout the life cycle, with male reproductive function being the most affected trait. In the present study, our main aim was to check the progression of the two progenies 12 years after transplantation. For this we analyzed their survival and their vegetative and reproductive traits. According to our results, levels of ID were similar to those obtained in the previous study, with some factors decreased and thus varying with the age of the studied individuals. Vegetative parameters were found to have a greater influence than reproductive ones (δ = 0.56 vs. δ = 0.36) on overall ID. As indicated by the global ID (δ = 0.72) the populations have a mating system that is intermediate between outcrossing and a mixed system. Furthermore, the lower male reproductive capacity of the selfed individuals has been maintained over time. Our study also demonstrates the importance of studying the ID value throughout the life cycle of plants.