Productivity, Stability, and Adaptability of Onion Genotypes Using Additive Main Effects and Multiplicative Interaction and Mixed‐Model Analysis

Onion ( Allium cepa L.) is a vegetable crop of both nutritional and medicinal importance. Bulb development is strongly dependent on the interaction between photoperiod and temperature, which drives the adaptation of genotypes to specific growing conditions. The objective of this study was to assess the agronomic performance of different onion genotypes across diverse environments, focusing on stability and adaptability through the Additive Main effects and Multiplicative Interaction (AMMI) analysis and mixed‐model (REML‐BLUP) methods using the harmonic mean of relative performance of genotypic values (MHPRVG). Six genotypes were tested in a randomized complete block design across three growing seasons: one in Barra do Rio Azul–RS and two in Florianopolis–SC. Evaluated traits included bulb production (classified by transverse diameter), total yield, percentage of commercial bulbs, and resistance to Botrytis squamosa . High commercial quality was noted, with 85.3% commercial bulbs for genotype PO‐39 achieving 28.26 t ha ⁻¹ total yield, confirming the importance of balancing yield and quality in cultivar selection. The AMMI model proved effective in identifying onion genotypes with high yield potential and wide adaptability, consistent with the MHPRVG mixed‐model results. These findings offer guidance for future research and breeding strategies, ensuring that new onion varieties meet market demands and are economically viable for producers.