The Organization for Tropical Studies (OTS) has played a pivotal role in our understanding of tropical ecosystems' structure and function. For more than fifty years, OTS has contributed to the training of three generations of tropical biologists and facilitated, supported, and promoted leading-edge research in its field stations. Plant reproductive ecology and genetics have been a significant focus of OTS research since the early 1960s, and Dr. K.S. Bawa made a significant contribution to the advancement of this field. His work improved our understanding of the diversity and evolution of breeding systems in tropical forests, their phenology and pollination ecology, and their mating and genetic structure. We argue that his work inspired other tropical biologists' work and used the work of one of the authors for illustration when appropriate. We point out the need for research in critically important topics to slow down biodiversity loss, prevent the collapse of tropical systems in a changing climate, and the emergence of zoonotic disease. We suggest future research topics for the OTS field stations, including in plant reproductive biology.