Table 2.

Bacterial isolates obtained from rhizosphere soil of Welsh onion and onion in isolation trial 1–4

Phylum	Genus	Number of species on medium
		From Welsh onion rhizosphere								From onion rhizosphere
		Trial 1		Trial 2		Trial 3		Trial 4
		R2Aa	1/4 TSAb	R2A	R2A-C/Tc	R2A-C/T	PSR2A-C/Td	PSR2A-C/T	PSR2A-C/T/Ne	PSR2A-C/T	PSR2A-C/T/N
Bacteroidetes	Flavobacterium						5	5		4
	Chryseobacterium	1		1		4	8	6	1	5	3
	Niabella	2		2	14	9	2	4		6	6
	Chitinophaga							1	2	1	2
	Niastella	1				2
	Dyadobacter								1
	Taibaiella			1		1	1			2
	Flavitalea					1
Proteobacteria	Sphingomonas	22	1	6							1
	Pseudoxanthomonas		10							1
	Ralstonia							3		2
	Sphingopyxis	1		1					1
	Frateuria	1
	Luteibacter	1
	Lysobacter	1
	Rhodanobacter	1
	Pseudomonas		1
	Sphingobium		1
	Stenotrophomonas			1			2
	Variovorax								1
Actinobacteria	Microbacterium	3	20				1		5		2
	Leifsonia			1					3	2	5
	Mycobacterium	1		1
	Aeromicrobium	1
	Cellulosimicrobium	1
	Rhodococcus	1
	Terrabacter							1
	Agrococcus								1
Total yellow/orange bacterial colonies		38	33	14	14	17	19	20	15	23	19
Total bacterial colonies		97	49	121	106	169	183	248	201	132	155

^aReasoner’s 2A agar

^b1/4-strength tryptic soy agar

^cReasoner’s 2A supplemented with cycloheximide and tobramycin

^dPhosphate separately autoclaved R2A supplemented with cycloheximide and tobramycin

^ePhosphate separately autoclaved R2A supplemented with cycloheximide, tobramycin, and NaCl