Genetic structure in cultivated quinoa (Chenopodium quinoa Willd.), a reflection of landscape structure in Northwest Argentina

Abstract

Quinoa (Chenopodium quinoa Willd.), one of the main crops domesticated in the Andean highlands 1,000 of years ago, played an important role as a protein source. 35 germplasm accessions collected along the Northwest Argentina (NWA) region were studied using 22 microsatellite (SSR) markers. Results showed a great level of genetic diversity, differing from previous reports about the geographical distribution of quinoa variability. All SSR loci analysed were highly polymorphic detecting a total of 354 alleles among all populations, with an average of 16 alleles per locus. Cluster analyses grouped the accessions into four main clusters at the average genetic distance level (0.80), each of which represented a different environment of the NWA region: Puna (UHe = 0.42, ±0.07 SE), Dry Valleys (UHe = 0.27, ±0.05 SE), Eastern Humid Valleys (UHe = 0.16, ±0.04 SE) and a transition area with high altitudes between the last two environments (UHe = 0.25, ±0.03 SE). An eastward decreasing genetic diversity gradient was found. AMOVA analyses showed a strong genetic structure: a high population subdivision relative to the grouping by region (Fsr = 0.47) together with a high genetic differentiation among populations (Fst = 0.58) and a heterozygous defect (Fis = 0.63) in each of them. The variability structure, a reflection of the structure of the NWA landscapes, is discussed in connection with environmental variables.

Discontinuities in quinoa biodiversity in the dry Andes: an 18-century perspective based on allelic genotyping

“…120 Estimates of the diversity indices and the selfing rates of the 19 populations sampled are summarized in table SI-3.3. Expected heterozygosity (He) in the subset of modern quinoas showed highly variable 122 values (range 0.02-0.70), consistent with those found in an independent study on the same samples (26). Similarly, selfing rates (s(F is ) and s(LnL)) appear highly variable without any clear geographical 124 pattern.…”

“…The quinoa crop in the dry Andes of Argentina provides a case study for investigating these issues since local conditions of low temperature and air dryness allowed for the conservation of 84 abundant biological material in what once were residential places, granaries or tombs (24,25). In modern quinoa samples, molecular markers reveal a diversity essentially shaped by broad 86 biogeographic features separating-among others-quinoas from temperate highlands, arid highlands, mid-and high-altitude valleys, and western versus eastern lowlands (26). Molecular 88 genotyping, applied to ancient samples, should thus allow for tracking quinoa biodiversity in space and time, providing a new tool to investigate the agrarian economy of past societies and go further 90 in-depth into the history of human-plant relationships (27).…”

“…They provided well-preserved quinoa seeds, with a broad 98 chronological range spanning the time of early husbandry (ca 1800 BP), to periods of stable agropastoralist societies (ca 1400 BP) and complex corporative societies (ca 800-700 BP). To evaluate the 100 relationship of these ancient quinoas with the present-day germplasm, we studied a reference panel of quinoas collected in 2006-2007 from different environments in the Andean highlands of Argentina 102 (26,30) (Fig 1A, SI-2 Table). Some archaeological sites supplied both dark and white seeds, which allowed us to explore the diversity of cultivated quinoa (generally white-seeded) and their weedy 104 relatives (all dark-seeded).…”

Effects of Sowing Time on the Seed Yield of Quinoa (<i>Chenopodium quinoa</i> Willd) in South Kanto, Japan

“…Quinoa (Chenopodium quinoa WILLD) is a crop species that has been domesticated in South America since 1000 years [1] [2]. At present, this species is distributed from Colombia to Southern Chile and from sea level up to >4000 m above sea level.…”

Plant growth dynamics and root morphology of little-known species of Chenopodium from contrasted Andean habitats

“…In quinoa, genetic differentiation corresponding to broadscale ecogeographic patterns has been inferred from molecular markers (Del Castillo et al 2007;Costa Tártara et al 2012), morphological traits (Rojas 2003;Bertero et al 2004;Bhargava et al 2007), or both (Anabalón Rodríguez and Thomet Isla 2009). However, this information is still lacking for its relatives, and in all cases, the root traits of these Andean chenopods remain largely unknown despite their crucial role for the capture of soil water and nutrient resources.…”