Evaluation of Trichoderma isolates as potential biological control agent against soybean charcoal rot disease caused by Macrophomina phaseolina

Figures & data

Table 1. Inhibition percentage of radial growth of M. phaseolina colonies affected by T. harzianum isolates in the in vitro dual culture and volatile production tests.

	Growth inhibition percentage (%)
Antagonist isolates of T. harzianum	Dual culture test	Volatile production test
T2	45.23^b	51.31^b
T10	44.13^b	43.30^c
T12	72.31^a	63.36^a

Note: Results are expressed as mean values. Similar letters are not significantly different from each other at 5% probability.

Figure 1. Dual culture test (A–C) and volatile metabolites production test (E–G) on PDA plates showing the mycelial growth inhibition.

Figure 2. Mycelial interaction between T. harzianum T12 and M. phaseolina.

Table 2. Sclerotia population of M. phaseolina pathogen in different regions of Mazandaran Province.

Collection site (Mazandaran Province)	Sclerotia population
Jooybar	32
Neka	28
Kiakola	22
Sari	19
Behshahr	17
Ghaemshahr	14

Note: Sclerotia population is described as the number of sclerotia per gram of soil.

Table 3. Soil physical and chemical properties from the experimental field (Jooybar).

Soil texture (%)			Soil mineral composition (mg/kg)							Soil chemistry*
Clay	Slit	Sand	N	P	K	Fe	Mn	Zn	Cu	TNV	OC	pH	ECe
28	56	16	12.2	20	40	11	0.5	0.6	0.03	27	1.4	7.8	6.8

Note: *Total neutralization value (TNV, %); organic carbon (OC, %); electrical conductivity (ECe, dS/m). Results are expressed as mean values.

Table 4. Analysis of variance for the field assessment studies on the efficacy of T. harzianum isolates as biological control agents against M. phaseolina charcoal rot pathogen.

		Mean square (MS)
Source of variation (SOV)	Degree of freedom (df)	Plant disease index	Stem length	Root length	Seed weight
Rep	3	1.1276^ns	2.0591^ns	0.0649^ns	0.6766^ns
Treatments	6	9.8526**	1.4545^ns	0.2056**	1.6023*
Error	18	0.1906	0.7561	0.0397	0.5436
Total	27	–	–	–	–
CV%	–	10.9821	10.0312	3.9946	4.4530

Note: Coefficient of variance (CV); non-significant (^ns); significant at 5% and 1% probability, respectively (* and **). Results are expressed as mean values.

Table 5. Evaluation of the efficacy of T. harzianum isolates as biological control agents against M. phaseolina in the soil incorporation and seed inoculation techniques.

Method of inoculation	T. harzianum isolates	Plant disease index (%)	Stem length (cm)	Root length (cm)	Thousand kernel weight (g)
Soil incorporation	T2	21.13^b	76.44^b	26.53^a	271.61^b
	T10	14.75^c	70.48^b	23.04^b	271.79^b
	T12	11.98^c	81.88^ab	26.14^a	283.24^a
Seed inoculation	T2	15.43^c	65.27^c	24.80^b	269.23^b
	T10	6.99^d	86.59^a	23.77^b	287.96^a
	T12	5.55^d	87.38^a	26.68^a	294.45^a
Control	−	49.06^a	61.65^c	20.56^c	232.57^b

Note: The means were compared by Duncan's multiple range test (DMRT). Results are expressed as mean values; similar letters are not significantly different from each other at 5% probability.

Figure 3. Results of the field study for the soybean stem (A) root (B) and seedlings (C) from the plots treated with T12 suspension of T. harzianum.