Question: What pseudocereal was a former staple of the Aztec empire?
About the article "Cereal", section "Production".

Candidate passages:
  "Aztec" (1980) : A story of the Aztec empire just before and during the arrival of the Spanish.
"Aztec Autumn" (1997), a story of the Aztecs following the Spanish conquest.
Aztec series.
Additional books in the series ("Aztec Blood", 2002; "Aztec Rage", 2006; "Aztec Fire", 2008, "Aztec Revenge", 2012) were written by Robert Gleason, Jennings' former editor, and Junius Podrug, working from notes left by Jennings. 
The following table shows the annual production of cereals in 1961, 2010, 2011, and 2012 ranked by 2012 production.
All but buckwheat and quinoa are true grasses (these two are pseudocereals).
Maize, wheat, and rice together accounted for 89% of all cereal production worldwide in 2012, and 43% of all food calories in 2009, while the production of oats and triticale have drastically fallen from their 1960s levels.
Other grains that are important in some places, but that have little production globally (and are not included in FAO statistics), include:
 Teff, an ancient grain that is a staple in Ethiopia.
It is high in fiber and protein.
Its flour is often used to make injera.
It can also be eaten as a warm breakfast cereal similar to farina with a chocolate or nutty flavor.
Its flour and whole grain products can usually be found in natural foods stores.
 Wild rice, grown in small amounts in North America.
 Amaranth, an ancient pseudocereal, formerly a staple crop of the Aztec Empire and now widely grown in Africa.
 Kañiwa, close relative of quinoa.
Several other species of wheat have also been domesticated, some very early in the history of agriculture:
 Spelt, a close relative of common wheat.
 Einkorn, a wheat species with a single grain.
 Emmer, one of the first crops domesticated in the Fertile Crescent.
 Durum, the only tetraploid species of wheat currently cultivated, used to make semolina.
 Kamut, an ancient relative of durum with an unknown history.
Aztec philosophy was the school of philosophy developed by the Aztec Empire.
The Aztecs had a well-developed school of philosophy, perhaps the most developed in the Americas and in many ways comparable to Greek philosophy, even amassing more texts than the ancient Greeks.
Aztec philosophy focused on dualism, monism, and aesthetics, and Aztec philosophers attempted to answer the main Aztec philosophical question of how to gain stability and balance in an ephemeral world. 
The Pipiltzin (sg.
pilli) were the noble social class in the Mexica Empire.
According to Maria Motika's "Aztec History", these people were members of the hereditary nobility and occupied the top positions in the government, the army and the priesthood.
"Pipiltzin" helped increase social stresses which attributed to internal weaknesses of the Aztec Empire's downfall.
As the Aztecs began settling what would later become their homelands, an elite emerged (the "pipiltzin") that claimed descent from the Toltecs, the former empire of Central Mexico.
The new hereditary elite unified the clans that had been the center of Aztec life and paved the way for a conquest empire. 
Canihua is an indigenous pseudocereal food of the high Andes.
The domestication of canihua as a commercial human food crop is not complete.
For instance, more uniform ripening would improve the economics of commercial canihua production.