Identification of Salt Tolerant Black Quinoa (Chenopodium quinoa Willd.) Germplasm through Germination Screening

Salinity is a major environmental constraint limiting crop establishment, particularly during seed germination, one of the most vulnerable stages of plant development. Black quinoa (Chenopodium quinoa Willd.) represents a valuable but underexplored genetic resource with potential for cultivation in salt-affected environments. This study assessed the germination performance of 21 black-seeded quinoa accessions conserved in the germplasm bank of the Universidad Nacional Toribio Rodríguez de Mendoza (Peru) under increasing sodium chloride (NaCl) concentrations (0, 125, 250, 375, and 500 mM). Germination percentage, mean germination time, germination speed, and synchrony were evaluated over an eight-day period, together with seed biometric traits. Salinity significantly affected all germination parameters, reducing germination percentage, germination speed, and synchrony while delaying germination as NaCl concentration increased. Considerable variation among accessions was observed, indicating contrasting levels of tolerance. In particular, accession UNTRM-367-1093 maintained high germination (>90%) even at 500 mM NaCl, whereas several accessions exhibited substantial reductions under severe salt stress. Multivariate analyses performed at 375 mM NaCl successfully differentiated accessions into tolerant, intermediate, and susceptible groups, highlighting UNTRM-367-1093, UNTRM-367-1118, and UNTRM-367-1014 as the most promising genotypes. These findings demonstrate the existence of exploitable genetic variability for salinity tolerance within black quinoa germplasm and provide valuable candidates for breeding programs aimed at improving crop establishment and resilience in saline agricultural environments.