Peanut Seed Vigor Evaluation Using a Thermal Gradient

Table 1

Standard Germination^a, logistic growth parameter estimates, 95% confidence limits (CL^b), and vigor indices (Germ₈₀^b) for germination of seed lots of 11 runner type, and peanut from Georgia using a thermogradient germination assay.

			Parameter 𝑎^c			Parameter 𝑏1^c			Parameter 𝑏2^c
Cultivar	Year^a	Germination^a	Maximum rate	95% CL		Estimate	95% CL		Estimate	95% CL		Germ80
		%										GDD
AP-3	2006	93	92.4	±1.6	a^d	5.8	±1.4	a^d	0.18	±0.02	a^d	26
	2007	92	91.6	±1.4	a	3.3	±0.9	b	0.21	±0.02	a	25
	2008	87	82.5	±1.6	b	1.7	±0.7	c	0.18	±0.02	a	40
AT 3081R	2006	96	89.8	±2.1	a	8.6	±2.2	a	0.16	±0.02	a	27
	2007	91	84.6	±1.7	b	4.8	±1.2	b	0.17	±0.02	a	32
AT 3085R0	2006	98	91.9	±1.8	a	6.5	±1.5	a	0.17	±0.02	a	27
	2007	91	84.6	±1.7	b	4.8	±1.2	a	0.17	±0.02	a	34
	2008	78	74.6	±1.6	c	0.9	±0.5	b	0.19	±0.02	a	NA
C-99R	2006	83	72.4	±2.3	c	5.3	±1.7	a	0.14	±0.02	b	NA
	2007	91	61.7	±1.9	b	3.0	±1.2	a	0.17	±0.03	ab	NA
	2008	93	80.7	±1.4	a	0.8	±0.4	b	0.22	±0.02	a	43
Carver	2006	79	83.8	±2.2	a	6.3	±1.9	a	0.16	±0.02	a	34
	2007	—	80.1	±1.7	a	2.7	±0.9	b	0.20	±0.02	a	51
Georgia Green	2006	92	81.2	±1.7	b^d	4.2	±1.1	a^d	0.15	±0.02	b^d	47
	2007	91	82.2	±2.0	b	3.9	±1.2	a	0.17	±0.02	b	38
	2008	86	86.9	±1.3	a	0.8	±0.8	b	0.22	±0.02	a	33
Georgia-01R	2006	68	63.0	±3.1	a	8.5	±2.8	a	0.11	±0.02	b	NA
	2007	87	37.8	±1.8	b	1.0	±0.8	b	0.20	±0.05	a	NA
Georgia-02C	2006	93	81.1	±3.3	a	12.4	±2.6	a	0.09	±0.01	b	67
	2007	98	64.0	±1.8	c	3.1	±1.1	b	0.16	±0.02	a	NA
	2008	90	68.5	±1.4	b	0.9	±0.4	c	0.16	±0.02	a	NA
Georgia-03L	2006	93	69.7	±2.8	a	9.4	±3.3	a	0.15	±0.03	a	NA
	2007	88	52.2	±1.8	b	2.5	±1.3	b	0.20	±0.04	a	NA
Georgia-06G	2007	98	94.3	±1.6	a	3.6	±1.0	a	0.21	±0.02	a	30
	2008	90	91.6	±1.5	a	1.8	±0.5	b	0.16	±0.01	b	45
York	2007	95	62.0	±2.1	b	2.2	±0.9	a	0.15	±0.02	a	NA
	2008	90	88.2	±1.6	a	2.5	±0.7	a	0.14	±0.01	a	42

^aOfficial Georgia Crop Improvement Association testing regulations, 75% for certified seed by AOSA. Year seed were grown, and tested the following year prior to seed planting.
^bAbbreviations: CL, confidence limit; Germ₈₀, cumulative growing-degree day value at 80% germination; NA, not applicable as the seed lot of that cultivar did not achieve 80% germination over the duration of the assay; GDD, growing-degree day.
^cParameter estimates calculated by nonlinear regression equation, 𝑌=𝑎/1+[((𝑎−𝑏1)/𝑏1)∗e^{(−𝑏2𝑥)}] for seed germination with respect to time based on GDD accumulation: 𝑎 is the height of the horizontal asymptote at a very large 𝑋, 𝑏1 is expected value of 𝑌 (cumulative germination) at time 𝑋=0, and 𝑏2 is a measure of growth rate.
^dValues for each parameter within a column for each cultivar followed by the same letter are not significantly different at the 5% probability level. General linear models procedures were used with mean separation using 95% asymptotic confidence intervals. To obtain the equation for the respective regression line in Figure 1, the parameters from this table are used.