Genotype-by-Environment Interaction Stability Analysis of New Quinoa (Chenopodium quinoa Willd.) Varieties in the Mediterranean Zone of Chile

Quinoa (<i>Chenopodium quinoa</i> Willd.), a crop native to the Andean region, exhibits variable performance in yield components under rainfed Mediterranean conditions. Consequently, identifying varieties that demonstrate stability in key agronomic traits-regardless of environmental fluctuations-is essential for enhancing crop reliability and productivity. In this work, new five varieties belonging to the sea-level ecotype (Pangal, Nieves, Pincoya, Chucao and Regalona), with superior performance to local materials used by farmers in terms of uniformity, stability, yield characteristics, grain diameter, thousand-grain weight, protein percentage, and saponins, were established in three environments (Pichilemu 34°29' S/72°01' W, Coihueco 36°42' S/72°42' W, Cañete 37°51' S/73°24' W) during two consecutive seasons (2019/2020, 2020/2021). Data analysis confirmed narrow variability among the varieties analyzed and between season and environment in all characteristics evaluated. The Pichilemu area (close to the coast) was the most productive over the two years of cultivation studied, with grain yields reaching 2975 kg·ha^-1. In the Cañete (coastal) and Coihueco (foothill) environments, grain yields were 2892 and 2453 kg·ha^-1, respectively. The Pangal variety (pearl) had the highest grain yield, reaching 3162 kg·ha^-1 in all environments. Nieves (white) variety had the best grain diameter (GD = 1.88 mm) and the best thousand-grain weight (TGW = 3.10 g). Regarding grain protein concentration, the Pincoya (black) variety had the highest score (GP = 16.31%). The lowest concentration of Saponin was obtained in Chucao (red) variety (GS = 1.46%). The Additive Main Effects and Multiplicative Interaction (AMMI) analysis did not identify any variety that exhibited greater yield and stability. Consequently, over the two years of study, the Nieves and Pangal varieties presented the best yield in the Pichilemu environment, with 3673 and 3788 kg·ha^-1, respectively. These varieties also stood out in the Cañete environment as obtaining the best yields (3547 and 3169 kg·ha^-1); however, they did not obtain the highest yield in the Coihueco environment. The Chucao variety was considered to have greater stability obtaining average yield in all study environments. This study presents a comprehensive phenotypic characterization of newly developed varieties, offering insights into their adaptive relationships with Mediterranean environments. To further elucidate the influence of environmental stressors on agronomic performance and grain quality traits, future trials are recommended in more extreme ecological settings.