ABSTRACT
Background: Maize in Mexico exhibits great genetic diversity, maintained by traditional practices of indigenous and non-indigenous communities, the same practices that have led to crop diversification over centuries. As one of the main staple crops worldwide, safeguarding the genetic diversity of maize is paramount to food security.
Aims: This study evaluated the genetic diversity and population structure of traditionally cultured maize landraces in a rural seasonal agricultural community in Veracruz, Mexico, in order to learn how traditional practices shape these landraces, and propose strategies for their preservation.
Methods: We analysed 118 individual maize samples belonging to five morphotypes (white, yellow, black, red and mottled) with eight microsatellite markers.
Results: We encountered high genetic diversity, according to expected heterozygosity (He = 0.61). However, inbreeding coefficient and gene flow values suggested the existence of assortative mating, which causes low genetic differentiation. Population structure analysis identified three genetic pools, independent of grain colour. These findings suggest that all morphotypes belong to the same population, which is sub-structured due to assortative mating and gene flow related to local agronomic management.
Conclusions: Current management practices in this community could lead to genetic erosion. In order to preserve diversity, wider regional seed exchange and selection for morphological diversity could be implemented.
Acknowledgements
We are grateful to all the women in Ocotepec for sharing their time and knowledge with us and for providing us with biological material for the present study. We thank Dr. Eduardo Sandoval-Castro for his critical reading of the manuscript, Dr. Cecilio Mota-Cruz and Rafael Ortega-Paczka for their help in the maize landraces identification, Ana Gabriela Perroni-Marañón, Salvador Gonzalez and Marisol Gonzalez for field work assistance, Dulce M. Romero-García for her technical help with the amplification of microsatellite markers and their preparation for capillary electrophoresis, and Carlos Cultid for designing . Authors acknowledge Clara Yang for English proofreading of the manuscript.
Disclosure statement
No potential conflict of interest was reported by the authors.
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Notes on contributors
Karla Y. Leyva-Madrigal
Karla Y. Leyva-Madrigal is interested in the study of the diversity, conservation and improvement of maize, as well as the study of crop diseases.
P. A. Báez-Astorga
P. A. Báez-Astorga is interested in molecular biology, plant biodiversity conservation and biological control agents to assist crop growth.
S. Negrete-Yankelevich
S. Negrete-Yankelevich is a soil ecologist interested in the consequences of land use practices on soil conservation and food security in tropical areas.
A. Núñez-de la Mora
A. Núñez-de la Mora is a biological anthropologist. Her research focuses on the application of evolutionary anthropology to reproductive and health issues combining field and laboratory methodologies.
G. Amescua-Villela
G. Amescua-Villela is a psychotherapist specialising in children, couples and parents.
I. E. Maldonado-Mendoza
I. E. Maldonado-Mendoza is interested in the molecular ecology of the rhizosphere, the arbuscular mycorrhizal fungi of maize and antagonistic interactions between bacteria and fungi associated with maize.