Genotypic Characterization of Azotobacteria Isolated from Argentinean Soils and Plant-Growth-Promoting Traits of Selected Strains with Prospects for Biofertilizer Production

Table 2

Auxin production capacity of representative Azotobacter strains as determined by a colorimetric assay using the Salkowski reagent and results of rep-PCR clustering.

Strain	rep-PCR	Auxin production (µg mL^−1)
	group	Day 1	Day 2	Day 3	Day 5
A. chroococcum AT9	1	1.80±0.64^a	2.50±0.27^a	4.13±0.30^c	4.23±1.55^c
A. chroococcum AT11	1	1.10±0.41^a	4.97±1.27^a	12.26±0.25^a	12.34±2.07^b
A. chroococcum AT13	1	1.41±0.83^a	4.58±1.37^a	11.38±3.52^a	12.72±2.46^b
A. chroococcum AT22	1	2.08±0.09^a	8.54±2.02^a	12.62±0.61^a	13.25±1.54^b
A. chroococcum AT31	1	1.38±0.61^a	9.30±0.60^a	12.68±1.65^a	14.76±0.52^b
A. chroococcum AT28	1	2.16±0.81^a	7.81±0.44^a	14.80±0.10^a	14.81±0.93^b
A. chroococcum AT25	1	2.64±0.57^a	7.97±2.31^a	12.82±0.07^a	15.33±2.41^b
A. chroococcum AT39	1	1.59±0.40^a	6.01±1.09^a	12.92±1.40^a	15.36±0.03^b
A. chroococcum AT30	1	1.40±0.60^a	4.97±1.27^a	12.86±0.60^a	16.11±0.44^b
A. armeniacus AT33	2	1.92±0.32^a	5.95±0.29^a	9.86±0.45^b	9.69±1.06^b
A. salinestris AT18	3	1.72±0.27^a	2.09±1.08^a	3.42±0.21^c	2.22±1.59^c
A. salinestris AT19	3	1.34±0.09^a	6.09±0.43^a	15.38±0.68^a	18.09±0.98^a
A. salinestris AT14	3	2.15±0.08^a	3.41±0.69^a	12.38±0.37^a	19.47±0.48^a
A. salinestris AT42	4	1.90±0.33^a	3.64±0.30^a	5.14±0.76^c	5.93±1.69^c
A. salinestris AT29	4	1.24±0.76^a	3.32±0.60^a	7.21±0.40^b	10.62±1.73^b
A. salinestris AT37	5	0.96±0.55^a	1.82±0.08^a	5.22±1.28^c	6.25±0.08^c
A. salinestris AT12	5	1.45±0.60^a	2.91±0.43^a	8.23±0.12^b	13.59±1.30^b
A. salinestris AT10	6	1.38±0.13^a	3.20±0.72^a	5.51±0.15^c	6.58±2.38^c

Auxin concentrations were determined after 1, 2, 3, and 5 days of growth in liquid culture. Values are means of two replicates ± standard error (𝑁=2). Same letters in a column indicate no significant differences as determined by the DGC test (𝑃=0.05).