Table 2.

Estimated parameter values using the hydrothermal time model (HTT) for describing seed germination of sesame at five-constant Ts (15, 20, 25, 30, 35 ℃) at each of the following five different Ψs (0, −0.05, −0.1, −0.15, and −0.2 MPa). R² is the coefficient determination. σψ_b is the standard error. Ψ_b(50) is base water potential at the 50 percentile. θHTT is hydrothermal time.

Cultivar	Pirsabak 15	Shahkar 13	Averaged Values
HTT parameter
Ψb(50) (MPa)	−0.120	−0.120	−0.120
σψb (MPa)	0.148	0.148	0.148
θHTT (MPa °Ch−1)	43.20	38.40	40.80
kT (MPa °Ch−1)	0.104	0.1041	0.104
Cardinal Temperature
Tb (°C)	15	15	15
To (°C)	20	20	20
Tc (°C)	35	35	35
R2	0.86	0.97	0.91