SUMMARY
Quinoa has been cultivated since centuries in the Andean region as a seed crop by indigenous communities. The crop has gained renewed interest because of its highly nutritious grain with high-quality protein rich in essential amino acids, and several bioactive compounds, along with its ability to grow under stress conditions. Despite the importance of the crop, limited research work on breeding aspects has been undertaken, leading to lack of information on the understanding of levels of variability of genotypes for different traits and their interactions. The aim of the present study was to assess and quantify the early response to mass selection in two quinoa landraces in highland conditions. Mass selection experiments were conducted during two successive crop seasons using eleven morphological traits. Correlation, genetic gain (gg) per selection cycle and principal component analysis was carried out. Only plant height (PH) and number of branches (NB) presented changes between selection cycles in both germplasm lines. Grain yield per plant (GYP) was positively correlated with inflorescence length (IL), stem diameter (SD) and plant weight (PW) for both quinoa lines. The results obtained would be useful to facilitate selection of the most relevant variables of quinoa considering its variation and interactions in the highland environment in Chile.