Genomic analyses of wild and cultivated bacanora agave (Agave angustifoliavar.pacifica) reveal inbreeding, few signs of cultivation history and shallow population structure

Abstract

Due to the recent increase in demand for agave-based beverages, many wild agave populations have experienced rapid decline and fragmentation; whereas cultivated plants are now managed at monocultural plantations, in some cases involving clonal propagation. We examined the rela-tive effect of migration, genetic drift, natural selection and human activities on the genetic reper-toire of Agave angustifolia var. pacifica, an agave used for bacanora (an alcoholic spirit similar to tequila) production in northwestern Mexico. We sampled 34 wild and cultivated sites and used over eleven thousand genome-wide SNPs. We found shallow genetic structure among wild sam-ples, although, detected differentiation between coastal and inland sites. Surprising-ly, no differentiation was found between cultivated and wild populations. Moreover, we detected moderate inbreeding (FIS ~ 0.13) and similar levels of genomic diversity in wild and cultivated agaves. Nevertheless, the cultivated plants had almost no private alleles and presented evidence of clonality. The overall low genetic structure in A. angustifolia var. pacifica is apparently the re-sult of high dispersibility promoted by pollinators and possibility of clonal reproduction. Incipi-ent cultivation history and reliance on wild seeds and plants are probably responsible for the ob-served patterns of high genetic connectivity and considerable diversity in cultivated samples