Drying kinetics and physiological quality of Solanum aethiopicum seeds

ABSTRACT The drying process is paramount for maintaining seed quality, where the temperature during this process directly influences germination and vigor, especially for vegetable species harvested with high moisture content. This research aimed to determine and model the drying curves of S. aethiopicum (cultivar Tinguá-verde-claro) seeds at temperatures of 35, 38, 41, and 44 ºC, as well as to evaluate the physiological quality of the seeds after drying. A completely randomized design was used, with four drying temperatures (35, 38, 41, and 44 ºC) and four replicates. Nine mathematical models were fitted using the non-linear regression analysis by the Gauss-Newton method, and the goodness of fit was assessed based on the magnitude of the coefficient of determination (R2), chi-square test (χ2), relative mean error (P), and estimated mean error (SE). Seed quality was evaluated by germination test (G), electrical conductivity (EC), and accelerated aging (AA). The Modified Midilli model best represents the drying curves of S. aethiopicum seeds at the studied temperatures. Seeds with higher germination and vigor, meaning lower electrical conductivity values and higher germination rates after accelerated aging, are achieved through drying at 35 and 38 ºC.