View Full Table | Close Full ViewTable 5.Coefficients for the nonlinear regression using a dose response model of cereal rye percentage control as a function of phenological development where Y is % cereal rye control (%); d is the % control at the upper growth stage limit; e is the effective growth stage 50, the growth stage producing a response half-way between d and the lower limit; and b is the relative slope around e (% control/growth stage) (Ritz and Streibig, 2005). Analysis was conducted by year with cultivars pooled and by cultivar within years to test for significance of parameter estimates. Due to lack of data at the lower range of growth stages for Aroostook rye in 2006, differences in cultivars in 2006 could not be tested. The null hypothesis in this case is formulated as a ratio of estimates, and therefore the t test is comparing the observed ratio with a value of 1. The P values are probability of getting a t statistic greater than the calculated t value. Values in parentheses are the standard error.