Botanical context for domestication in South America

Abstract

Quinoa domestication studies based on seed’s morphological traits and conducted in the Central Andes region concluded that it occurred somewhere around Lake Titicaca before 3000 BC. Recent genetic studies showed quinoa (an allotetraploid) resulting from the fusion of two diploid species (carrying the A and B genomes), one Eurasian and one American (probably in North America), from where a tetraploid ancestor migrated to South America. Extant wild relatives are found from the U.S. to South America, and quinoa is part of a complex of domesticates including Chenopodium berlandieri spp. jonesianum and nuttalliae. Quinoa domestication in the Andes appears as a diffuse process occurring in a wide area within the Bolivian Highlands. Here, we pose the hypothesis and provide evidence that quinoa was domesticated twice: in the Andes and Central Chile. The domestication syndrome in quinoa included bigger seeds with a reduced testa width and a range of colours, plus a wide array of plant architectures, panicle morphologies and reproductive partitioning. We widen those studies including root traits and phenological adaptations to a wide climatic range. Finally, the hypothesis that reduced testa width can be related more to reduced restrictions to seed growth than to a reduced dormancy is presented.