Pioneer experimentation with Chenopodium quinoa Willd has shown its adaptability to grain production in the Brazilian savannah. Its fruits (achene type) are cylindrical, flat and germinate quickly in the presence of moisture, after reaching physiological maturity. At its early phase of development, quinoa can be confounded with the weed Chenopodium album, known in Brazil as 'ançarinha- branca'. Their basic differences become more visible after flowering: profuse branching, with axilary and terminal racemes in C. album, contrasting with C. quinoa, whose panicles are terminal and similar to sorghum; the pericarp has a light colour, contrasting with black in C. album. Quinoa BRS Piabiru, the first quinoa cultivar brought to Brazil, presents 190 cm height, of which 45 cm is occupied by the panicle; physiological maturity at 145 days; resistance to lodging; average grain weight of 2.42 g 1,000-1, with yields of 2.8 t ha-1 (grains) and 6.6 t ha-1 (total biomass). The C. album seeds are very small (0.52 g 1,000-1), germinate gradually and remain in soil for many years infesting crops. The differences in number of chromosome leading to impediment to natural crosses, and morphological differences detected during experimentation, show that the two species are distinguishable and that quinoa displays adaptability characteristics for commercial cultivation, contrasting with C. album, which displays typical weed behaviour.
quinoa; 'ançarinha-branca' weed; morphology
