A personal perspective on 50 years of research on plant reproductive biology: From natural history to genomics

This review summarizes the research contributions of Spencer C.H. Barrett during the past 50 years on the reproductive biology of plants. Topics covered include sexual polymorphisms, especially heterostyly and dioecy, the ecology and genetics of mating-system transitions, and the mechanisms influencing sex-ratio variation and sex chromosome evolution with examples from diverse angiosperm species. The article commences with a summary of the author’s early life and the influences that later shaped his research at the University of Toronto. Case studies are presented in chronological order and highlight the diversification of research methods, including field experiments, comparative approaches and genomic analyses, that have enabled efforts to address more general questions in evolutionary biology. Two interwoven themes are evident in the review: the importance of natural history observations as a basis for many of the research questions pursued; and the key role of collaborations with trainees and colleagues in Canada and overseas. The author also points out that unexpected discoveries and new research pathways often arise by chance and an open mind can be a key ingredient to a successful research career. The review concludes by identifying several under-studied areas in plant reproductive biology that would be worthwhile to pursue in the future.