Table 4.

Parameter values of the four-parameter log-logistic equation for calculating GR₅₀ values of Digitaria sanguinalis populations in whole-plant dose–response experiment.

Population	Regression Parameters a				GR50 b ± SE c (g a.i. ha−1)	RI d
	c	d	b	R2
HLJ	-0.60 ± 3.59	94.95 ± 2.93	-4.32 ± 0.93	0.9973	74.20 ± 4.88	2.45
BJ	-0.34 ± 1.64	97.22 ± 1.83	-3.63 ± 0.43	0.9993	54.23 ± 1.76	1.79
AH	-0.74 ± 2.11	96.75 ± 2.55	-3.22 ± 0.40	0.9988	46.61 ± 2.26	1.54
JL	0.32 ± 1.87	97.04 ± 1.53	-3.84 ± 0.50	0.9989	36.67 ± 1.54	1.21
SD22	-0.43 ± 0.74	99.18 ± 1.14	-3.30 ± 0.19	0.9998	30.23 ± 0.52	–

^a $y=c+(d-c)/[1+{(x/G{R}_{50})}^b]$ , where x is the applied dose of herbicide, c is the lower limit of reaction; d is the upper limit of the reaction; b is the slope of the curve and y is the fresh weight of the corresponding dose.

^bGR₅₀, herbicide dose that reduces fresh weight by 50%.

^cSE, standard error of the mean.

^dRI, the resistance index.

The symbol "-" represents a null value.