Morphological and Genetic Diversity of Maize Landraces Along an Altitudinal Gradient in the Southern Andes

This research paper was developed in the framework of the project “Conservación y uso sostenible de los recursos fitogenéticos locales para la alimentación y la agricultura (RFAA) para contribuir a la seguridad alimentaria de los pequeños agricultores de Argentina” funded in the 4th project cycle of Benefit Sharing Fund (BSF) of the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA)of the Food and Agriculture Organization (FAO), gave during the Tenth Session of the Governing Body of ITPGRFA. Maize (Zea mays ssp. mays) is a major cereal crop worldwide and is traditionally commercialized and cultivated almost all over the Americas. The northwestern region of Argentina (NWA) constitutes one of the main diversity hotspots of the Southern Andes, with contrasting landscapes and a large number of landraces. Despite the extensive collections performed by the “Banco Activo de Germoplasma INTA Pergamino, Argentina” (BAP), most of them have not been characterized yet. This research paper contains the information on the morphological and molecular evaluation of 30 accessions collected from NWA, along an altitudinal gradient between 1120 and 2950 meters above sea level (masl). Assessment of morphological variation in a common garden allowed the discrimination of two groups, which differed mainly in endosperm type and overall plant size. Although the groups retrieved by the molecular analyses were not consistent with morphological clusters, they showed a clear pattern of altitudinal structuring. Affinities among accessions were not in accordance with racial assignments. Overall, our results revealed that there are two maize gene pools co-existing in NWA, probably resulting from various waves of maize introduction in pre-Columbian times as well as from the adoption of modern varieties by local farmers. In conclusion, the NWA maize landraces preserved at the BAP possess high morphological and molecular variability. Our results highlight their potential as a source of diversity for increasing the genetic basis of breeding programs and provide useful information to guide future sampling and conservation efforts.