Documenting Cultural Selection Pressure Changes on Chile Pepper (Capsicum baccatum L.) Seed Size through Time in Coastal Peru (7,600 B.P.-Present). The chile pepper (Capsicum spp.) was independently domesticated in Mexico, the Amazon region, and the Central Andes of South America, though the exact nature of when, where, and how this process took place is uncertain. Current knowledge of early Capsicum domestication is further hindered by the general reliance on the rare preservation of Capsicum fruit, specifically the calyx morphology, from archaeological sites to chart the presence of various Capsicum species through space and time. Capsicum seeds, which are recovered in greater abundance from archaeological contexts, present a prime opportunity for studying selection pressures on Capsicum. Many plants exhibit signs of morphological change through time related to changes in selection pressures and the process of domestication. In food plants, a common occurrence is the change in seed size, which suggests correlating changes in fruit size. To investigate these changes on a species level, we developed the first systematic identification system based on qualitative and quantitative attributes for domesticated Capsicum seeds. In the course of our analysis, we found that C. baccatum L. seeds from Peru (ca. 7,600 cal. B.P. through modern day) change in size over time, suggesting human-influenced selection. Here, we demonstrate that C. baccatum L. seeds increase in size through pre-Columbian times. Remarkably, following Spanish conquest (post-1532 C.E.), the reduction in the size of seeds back to earlier pre-Columbian times suggests a loss of selective pressure for seed size in this particular Capsicum species. © 2014 The New York Botanical Garden.