Between 1948 and 1972, research increasingly treated seed processing as a physiological and biochemical problem, focusing on measurable vigor indicators such as seed coat integrity, leakage during imbibition, standardized germination tests, and rapid respiration-based assays. The approach favored quantitative metrics like solute leakage, TTC reduction, and early tannin estimation to predict vigor and field performance, enabling reproducible testing across crops and environments. These methods linked laboratory measurements to practical seed quality decisions, shaping processing protocols and quality control practices that endured for decades.