Fig. 2. Relationship between final seedling emergence and thermal time (base temperature of 10°C) to 50% of final emergence (T₅₀) of pregerminated and dry seed, at two planting depths, for high-, medium-, and low-vigor seedlots in sterile and nonsterile soil. Data points represent individual replicates. Regression analysis for the sterile soil treatments were not significant and the equations are not shown. The symbols *, ** denote significance at P 0.05 and 0.01, respectively.