Physiological Vigor Assessment era
During the Physiological Vigor Assessment era (1948–1979), R. H. Ellis and E. H. Roberts stand as representative figures who helped define vigor testing as essential to seed quality. Ellis reframed seed quality around vigor indicators and developed protocols that link lab vigor measurements to subsequent field performance. Roberts advanced standardized vigor assays such as accelerated aging, solute leakage, and TTC reduction, clarifying how these tests predict germination under stress and stand establishment. Together with seed laboratories and ISTA standardization efforts, these authors fostered reproducible procedures that enabled cross-crop comparability in processing and lot management.