Morphological and eco-geographic diversity analysis of maize germplasm in the high altitude Andes region of Ecuador

Abstract

The Andean region of Ecuador is the place of origin of many maize landraces grouped into 24 races. Definition of priorities for maize diversity conservation in this region can be supported by the spatial identification of areas with a high eco-geographical and phenotypic diversity. Six hundred thirty-six maize samples were morphologically characterized using 14 descriptors and assigned to a distinctive race. Additionally, sampled farms were characterized by 12 environmental variables. From these data, maps of morphological and eco-geographical diversity were obtained by using techniques to determine eco-geographical and phenotypic distances and applying them to each geographical neighbourhood. The races Patillo Ecuatoriano, Racimo de Uva and Uchima exhibited high intra-racial morphological variation, particularly in the shape of the ear, kernel row layout, cob diameter and total kernel number. The highest number of different races was observed in Imbabura, Azuay and Chimborazo provinces. The highest levels of morphological diversity were found in three cells (10 × 10 km), located in Pichincha, Chimborazo and Loja provinces. Two ecological niches, located in Loja province, showed high levels of eco-geographical diversity. A comparison between diversity maps revealed shared hotspots of morphological and eco-geographical diversity in the central and southwest areas of Imbabura province. The Andean highlands of Ecuador are an optimal refuge for the conservation of maize diversity, and the criteria of eco-geographical and morphological diversity and race richness should be considered when defining priority in situ conservation areas.