Diversity of Maize Landraces in Germplasm Collections from South America

Abstract

In the Southern Cone there is a wide variety of maize landraces kept by small-scale farmers, which are of interest for the development of the crop at a worldwide scale. The countries of this region hold important ex situ maize collections in national and international Germplasm Banks, from missions that took place before the generalization of hybrids and transgenic cultivars. In order to avoid losses of genetic diversity and to promote their use in breeding programs, it is essential that these collections are adequately known and conserved. The aim of this study was to map the geographic distribution of the collections of maize from Argentina, Bolivia, Brazil, Chile, Paraguay and Uruguay, and to analyze its diversity based on the variable kernel type. Information about the accessions was obtained from the catalogues of maize genetic resources. The geographic distribution, Richness and Shannon Diversity Index were mapped and analyzed using software diva-gis. Results show an important geographic dispersal of the accessions and concentration patterns of the different grain types (floury, flint, dent, pop and sweet). Micro-centres of maize diversity are observed in the Central regions of Chile and Bolivia, Southern Paraguay, Northern Argentina and Uruguay. This paper contributes with a broader understanding of maize diversity in the Southern Cone and seeks to revalue regions where traditional agriculture is still practiced, encouraging new prospection plans and in situ conservation strategies.