The domestication of the chile pepper, Capsicum annuum: Genetic, ecological, and anthropogenic patterns of genetic diversity

Over the following four chapters, a multidimensional approach is utilized to contribute to the understanding of the domestication of C. annuum . A number of research tools (ecological, genetic, and sociological) are utilized to investigate the myriad of ways in which the genetic diversity of C. annuum is shaped during domestication and continues to be shaped. The organization of genetic diversity in the domesticated gene pool in a crop is the result of the effect and interaction of multiple factors that belong to the biological, environmental and human realms. An understanding of genetic diversity for conservation and utilization therefore requires a dissection and unraveling of these multiple factors and their interactions. In the following chapters, we describe our efforts to contribute to our collective understanding of the domestication of C. annuum.;We describe in detail the efforts made to assemble an unprecedented collection of wild Capsicum from Mexico. We report on the genotyping of this collection, how genetic diversity is partitioned amongst the wild populations, and the genetic clustering of these populations and their relationship to domesticated C. annuum. Of exceptional interest is one of the clusters contained all the domesticated C. annuum and wild populations from Tamaulipas, Nuevo Leon and the Yucatan. We followed this with a recounting of a new and unique use of an ecological tool, a species distribution model, which was used with a number of different variants of wild Capsicum presence data. Finally, we chronicled the seed saving and selection process amongst chile pepper farmers in central Mexico, finding that those planting varieties of dried chile continue to plant landraces, while those who plant varieties of fresh chiles use hybrid seed, purchased from multinational seed corporations.;On the basis of our collection and the genetic relationships uncovered, our results strongly support the hypothesis that C. annuum was domesticated in northeastern Mexico, somewhere near the borders of Veracruz, Tamaulipas and Nuevo Leon.