Selected rhizobacteria strains as potential growth promoters and biocontrol agents against chocolate spot disease in faba bean grown in pots

Figures & data

Table 1. Inhibitory effect of rhizobacteria species on mycelial growth of B. fabae under in vitro tests after 9 days.

Treatment	Inhibition of radial growth at 9 days incubation in (cm)	Percent of inhibition over control at day (9)
B. fabae only	8.33 ± 0.03
Chryseobacterium strain GY04	2.30 ± 0.05a	72.38%
Chryseobacterium proteolyticum GY05	3.03 ± 0.08b	63.62%
Pseudomonas chlororaphis GY07	3.17 ± 0.02b	61.94%
LSD (5%)	0.26

Values are mean ± Standard error of the mean of three replications, Means in each column followed by the same letter are not significantly different at p < .05 according to the LSD test (p ≤ 0.05).

Table 2. The effect of rhizobacteria species to control chocolate spot (Botrytis fabae) disease incidence and severity on local variety of faba bean using pot experiments.

Treatment	Days after sowing
	75				90
	%DI	(BCE)	%DS	(BCE)	%DI	(BCE)	%DS	(BCE)
B. fabae only	75	–	38.88	–	83%	–	37.28	–
Chryseobacterium strain GY04+B.fabae	19a	74%a	7.92a	79.62%a	27a	67.46%a	9.85a	73.57%
Chryseobacterium proteolyticum GY05+B.fabae	32b	57.3%b	25.32c	34.87%c	35.59b	57.12%b	17.48c	53.88%
Pseudomonas chlororaphis GY07+B.fabae	33%b	56%b	18.31b	52.90%b	34.05b	58.97%b	11.99b	67.83%

Note. %DI: percent disease incidence, BCE: biocontrol efficacy, %DS: percent of disease severity Values in each column followed by the same letter are not significantly different at p < .05 according to Tukey HSD analysis of Two Way ANOVA.

Table 3. The effect of rhizobacteria species to control chocolate spot (Botrytis fabae) disease incidence and disease severity on Dosha variety of faba bean using pot experiments.

Treatment	Days after sowing
	75				90
	%DI	(BCE)	%DS	(BCE)	%DI	(BCE)	%DS	(BCE)
B. fabae only	44.33	–	14.99	–	46.20	–	19.40	–
Chryseobacterium strain GY04 + B.fabae	7.69a	82.65a	3.61b	75.91b	23.52a	49.09a	12.77b	34.17c
Chryseobacterium proteolyticum GY05+B.fabae	11.36b	74.33b	4.44c	70.08c	26.31b	43.05b	11.40a	41.23b
Pseudomonas chlororaphis GY07+B.fabae	12.31b	72.23b	2.98a	80.12a	26.34b	42.98b	11.05a	43.85a

Note. %DI: percent disease incidence, BCE: biocontrol efficacy, %DS: percent of disease severity Values in each column followed by the same letter are not significantly different at p < .05 according to Tukey HSD analysis of two-way ANOVA.

Table 3.1. An interaction analysis among the chocolate spot disease severity at 90 DAS

hosts varieties and treatment group by two-way ANOVA.

Dependent variable: DS
Source	Type III Sum of squares	df	Mean square	F	Sig.
Corrected model	8294.052^a	7	1184.865	280.618	.000
Intercept	33765.752	1	33765.752	7996.933	.000
Treat	6031.645	3	2010.548	476.170	.000
Varity	1170.267	1	1170.267	277.161	.000
Treat * variety	1092.140	3	364.047	86.219	.000
Error	67.557	16	4.222
Total	42127.361	24
Corrected total	8361.609	23

^a R Squared = .992 (Adjusted R Squared = .988).

Table 4. Effect of rhizobacterial species inoculation on the growth parameters of faba bean local variety under pot conditions.

Treatment	SL(cm)	SFW(g)	SDW(g)	RL(cm)	RFW(g)	RDW(g)
B. fabae only	33.16 ± 0.7	24.33 ± 1.8	8.93 ± 0.08	10.86 ± 0.31	8.26 ± 0.58	3.26 ± 0.7
Chryseobacterium strain GY04 + B.fabae	44.63 ± 0.7b	31.50 ± 0.4b	11.24 ± 0.52b	15.12 ± 0.78b	11.33 ± 0.21	4.13 ± 0.88
Chryseobacterium proteolyticum GY05+B.fabae	40.86 ± 0.8c	25.93 ± 1.56 ns	10.36 ± 0.32c	12.60 ± 0.5c	10.23 ± 0.2	3.86 ± 0.03
Pseudomonas chlororaphis GY07+B.fabae	50.63 ± 0.3a	37.63 ± 1.64a	13.93 ± 0.32a	18.05 ± 0.12a	12.86 ± 0.12	5.20 ± 0.05
CV at p < 0.05	15.78	19.64	7.73	0.40	6.96	8.00

Note. Shoot length (SL), shoot fresh weight (SFW), shoot dry weight (SDW), root length (RL), root fresh weight (RFW) root dry weight (RDW). Values are mean ± Standard error of the mean of three replications, Means in each column followed by the same letter are not significantly different at p < .05 according to Fisher’s LSD, CV, coefficient of variance according to Tukey HSD analysis of two-way ANOVA.

Table 5. Effect of rhizobacterial species inoculation on the growth parameters of faba bean Dosha variety under pot conditions after 90 days.

Treatment	Shoot length	SFW	SDW	RL	RFW	RDW
B. fabae only	36.10 ± 0.55	23.66 ± 0.2	11.76 ± 0.14	12.83 ± 0.08	12.06 ± 0.17	5.20 ± 0.2
Chryseobacterium strain GY04 + B.fabae	52.00 ± 0.57b	30.40 ± 0.2	14.56 ± 0.28b	17.26 ± 0.03	15.00 ± 0.65a	9.00 ± 043a
Chryseobacterium proteolyticum GY05+B.fabae	46.66 ± 1.2c	28.30 ± 0.35	12.96 ± 0.33nc	14.73 ± 0.08	13.53 ± 0.31nc	7.33 ± 0.08b
Pseudomonas chlororaphis GY07+B.fabae	59.00 ± 1.52a	33.66 ± 0.44	16.60 ± 0.37a	20.66 ± 0.37	15.00 ± 1.95a	11.10 ± 0.17a
CV at p < 0.05	8.29	3.13	13.74	19.05	14.38	28.09

Note. Shoot length (SL), shoot fresh weight (SFW), shoot day weight (SDW), root length (RL), root fresh weight (RFW) Root dry weight (RDW). Values are mean ± Standard error of the mean of three replications, Means in each column followed by the same letter are not significantly different at p < .05 according to Tukey HSD analysis of Two Way ANOVA.

Table 6. An interaction analysis between faba bean varieties and treatments on the growth parameter (shoot length (SL), shoot fresh weight (SFW), shoot dry weight (SDW), root length (RL), root fresh weight (RFW) root dry weight (RDW)) by two-way ANOVA.

Tests of between-subjects effects
Source	Dependent variable	Type III Sum of squares	df	Mean square	F	Sig.
Corrected Model	Shoot length	1544.380^a	7	220.626	94.251	.000
	Shoot fresh weight	489.496^b	7	69.928	20.316	.000
	Shoot dry weight	128.201^c	7	18.314	65.855	.000
	Root length	220.810^d	7	31.544	59.598	.000
	Root fresh weight	113.846^e	7	16.264	8.998	.000
	Root dry weight	160.327^f	7	22.904	193.683	.000
Intercept	Shoot length	49431.527	1	49431.527	21117.064	.000
	Shoot fresh weight	20785.820	1	20785.820	6038.732	.000
	Shoot dry weight	3778.052	1	3778.052	13585.229	.000
	Root length	5594.623	1	5594.623	10570.102	.000
	Root fresh weight	3623.584	1	3623.584	2004.749	.000
	Root dry weight	903.931	1	903.931	7643.967	.000
treat	Shoot length	1294.610	3	431.537	184.352	.000
	Shoot fresh weight	455.011	3	151.670	44.064	.000
	Shoot dry weight	78.752	3	26.251	94.393	.000
	Root length	191.041	3	63.680	120.314	.000
	Root fresh weight	48.858	3	16.286	9.010	.001
	Root dry weight	48.933	3	16.311	137.931	.000
variety	Shoot length	224.482	1	224.482	95.898	.000
	Shoot fresh weight	4.250	1	4.250	1.235	.283
	Shoot dry weight	48.963	1	48.963	176.064	.000
	Root length	29.415	1	29.415	55.575	.000
	Root fresh weight	62.404	1	62.404	34.525	.000
	Root dry weight	98.051	1	98.051	829.153	.000
treat * variety	Shoot length	25.288	3	8.429	3.601	.037
	Shoot fresh weight	30.235	3	10.078	2.928	.066
	Shoot dry weight	.485	3	.162	.581	.636
	Root length	.353	3	.118	.222	.880
	Root fresh weight	2.585	3	.862	.477	.703
	Root dry weight	13.344	3	4.448	37.613	.000
Error	Shoot length	37.453	16	2.341
	Shoot fresh weight	55.073	16	3.442
	Shoot dry weight	4.450	16	.278
	Root length	8.469	16	.529
	Root fresh weight	28.920	16	1.807
	Root dry weight	1.892	16	.118
Total	Shoot length	51013.360	24
	Shoot fresh weight	21330.390	24
	Shoot dry weight	3910.702	24
	Root length	5823.901	24
	Root fresh weight	3766.350	24
	Root dry weight	1066.150	24
Corrected Total	Shoot length	1581.833	23
	Shoot fresh weight	544.570	23
	Shoot dry weight	132.650	23
	Root length	229.278	23
	Root fresh weight	142.766	23
	Root dry weight	162.219	23

^a . R Squared = .976 (Adjusted R Squared = .966).

^b . R Squared = .899 (Adjusted R Squared = .855).

^c . R Squared = .966 (Adjusted R Squared = .952).

^d . R Squared = .963 (Adjusted R Squared = .947).

^e . R Squared = .797 (Adjusted R Squared = .709).

^f . R Squared = .988 (Adjusted R Squared = .983).

Data availability statement

The data that support the findings of this study are available from the corresponding author [GYM], upon reasonable request.