Madras Agric. J. 92 (4-6) : 238-240 April-June 2005

Host range and cross inoculation studies on Macrophomina phaseolina from sunflower M.SURIACHANDRASELVAN, K.E.A. AIYYANATHAN AND R.VIMALA Dept. of Plant Pathology, Agrl. College and Res. Institute, Tamil Nadu Agrl. Univ., Madurai-625 104. Abstract: M. Phaseolina isolated from sunflower infected all the 22 plants tested but failed to infect finger millet, pearl millet, haryali, nutgrass, mookkuthipoondu and saranai. M. phaseolina isolates from sunflower, blackgram, greengram, cowpea, sesame and cotton were cross pathogenic. Sunflower and blackgram isolates were the most aggressive while those of sesame and cotton were the least virulent. There was a positive correlation between M. phaseolina infection and the crop plants belonging to botanical families Fabaceae, Pedaliaceae, Asteraceae and Malvaceae. Key words: Macrophomina phaseolina, Host range, Cross infection

Introduction The ubiquitous sclerotial fungus Rhizoctonia bataticola (Taub.) Butler (=Sclerotium bataticola Taub.) in its pycnidial stage is known as Macrophomina phaseolina (Tassi.) Goid. The fungus causes charcoal rot of several important crop species and is especially prevalent in arid, subtropical and tropical climates (Manici et al. 1995). In the semi-arid tropics, the crops, such as blackgram, greengram, cowpea, sunflower, sesame and cotton are normally used in rotations and intercropping systems. All these crops are infected by Macrophomina phaseolina. Host range and cross inoculation studies were carried out to determine the specificity of M. phaseolina, if any, and to obtain information that could be useful in managing this pathogen. Materials and Methods Host range The host range of sunflower charcoal rot pathogen, M. phaseolina was studied in pot culture experiment. The sand maize inoculum of M. phaseolina was added to the sterilized pot culture soil in earthern pots (30 cm) at 1:19 ratio (w/w) a week before sowing/planting the host plants. A total of 21 plant species belonging to nine botanical families (Table 1) were tested. The surface sterilized seeds/healthy

seedlings of the test host species were sown/ planted @ five numbers per pot. Three replications were maintained with four pots in each. The pots were maintained in the glasshouse with judicious, uniform and regular watering. The disease incidence was recorded at maturity phase of the plants and expressed as per cent charcoal rot incidence. Cross inoculation studies A pot culture experiment was conducted to study the cross inoculation of M. phaseolina among six different hosts. The pathogen isolated from different hosts was seperately multiplied in sand maize medium for 21 days. These inocula were separately mixed with the sterilized pot soil at 1:19 ratio (w/w) in earthern pots (30 cm) a week before sowing. Five wellmatured uniform sized and surface - sterilized, seeds of blackgram (cv. T9), greengram (cv. KM2), cowpea (cv. C. 152), sunflower (cv. CO2), gingelly (cv. SVPR 1) and cotton (cv. SVPR 1) were separately sown in these sets of pots. Three replications were maintained for each species with four pots in each. The pots were kept in the glass house with judicious, uniform and regular watering. The disease incidence was observed at the harvest stage and expressed as per cent incidence.

Host range and cross inoculation studies on Macrophomina phaseolina from sunflower

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Table 1. Host range of sunflower isolates of M. phaseolina (artificial inoculation) S.No

Common / names

Botanical name

Botanical family

Charcoal rot incidence (%)*

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Sunflower Blackgram Greengram Cowpea Soybean Chickpea Pigeonpea Groundnut Sunnhemp Maize Sorghum Finger millet Pearl millet Haryali Nut grass Parthenium Gingelly Cotton Manja Kadugu Castor Mookkuthi poondu Saranai CD(P = 0.05)

Helianthus annuus L. Vigna mungo (L.) Hepper Vigna radiata (L.) Wilczek Vigna unquiculata (L.) Walp Glycine max (L.) Merr Cicer arietinum L. Cajanus cajan (L.) Mallop Arachis hypogea L. Crotalaria juncea L. Zea mays L. Sorghum bicolor (L.) Moench Eleusine coracana Gaertn Pennisetum americanum Leeke Cynodan dactylon (L.) Pens. Cyperus rotundus L. Parthenium hysterophorus L. Sesamum indicum L. Gossypium hirsutum L. Cleome viscosa L. Ricinus communis L. Tridax procumbens L.

Asteraceae Fabaceae Fabaceae Fabaceae Fabaceae Fabaceae Fabaceae Fabaceae Fabaceae Gramineae Gramineae Gramineae Gramineae Gramineae Cyperaceae Asteraceae Pedaliaceae Malvaceae Cleomaceae Ei[jprbiaceae Asteraceae

88.3(70.12) 61.7 (5l.78) 58.3 (49.79) 51.7 (45.96) 48.3 (44.04) 33.3 (35.25) 23.3 (28.86) 13.3 (21.34) 28.3 (32.14) 16.7 (24.05) 21.7 (27.71) 0.0 (0.00) 0.0 (0.00) 0.0 (0.00) 0.0 (0.00) 23.3 (28.86) 56.7 (48.84) 38.3 (38.24) 21.7 (27.71) 36.7 (37.26) 0.0 (0.00)

Trianthima portulacastrum L.

Aizoceae

0.0 (0.00) 3.20

22

* Mean of three replications (Figures in parentheses are arcsine-transformed values)

Results and Discussion Host range M. phaseolina isolate from sunflower infected all the host plants tested except finger millet, pearl millet, haryali, nutgrass, mookkuthipoondu and saranai (Table 1). Pawar et al. (1978) also reported that sunflower isolate of M. phaseolina infected all the host plants tested except pearl millet, paddy, bhendi and brinjal. The pathogen was reported to be omnipresent infecting over 500 plant species (Jones and Canada, 1994). Singh et al. (1990) however found that mookkuthi poondu and saranai were also infected by the pathogen. It could be worthy to consider these facts while choosing the cropping sequence for the management of this disease.

Cross inoculation studies All the isolates of M.phaseolina from different crops were cross-pathogenic. The isolates from sunflower and blackgram were more aggressive while cotton and gingelly isolates were the least aggressive. Blackgram was the most susceptible followed by greengram, cowpea and sesame (Table 2). Similar observations were reported by Byadgi and Hegde (1985) and Manici et al. (1995). Diourte (1987) observed a general trend of M.phaseolina isolates being more aggressive towards the host species than towards the other host species. The positive correlation

M.Suriachandraselvan, K.E.A. Aiyyanathan and R.Vimala

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Table 2. Cross inoculation studies with M.phaseolina isolated from different host plants. Isolates Blackgram Greengram Cowpea Sunflower Gingelly Cotton Mean

Blackgram

Greengram

Cowpea

Sunflower

Gingelly

Cotton

Mean

93.3* (75.24) 81.7 (64.69) 68.3 (55.77) 61.7 (51.78) 38.3 (38.24) 36.7 (37.26) 63.3 (53.83)

83.3 (65.95) 93.3 (75.24) 66.7 (54.75) 58.3 (49.79) 33.3 (35.25) 35.0 (36.27) 61.7 (52.88)

81.7 (64.69) 71.7 (57.86) 70.0 (56.79) 51.7 (45.96) 31.7 (34.23) 26.7 (31.07) 55.6 (48.43)

36.7 (37.26) 23.3 (28.86) 21.7 (27.71) 88.3 (70.12) 21.7 (27.71) 13.3 (21.34) 34.2 (35.50)

33.3 (35.25) 45.0 (42.13) 38.3 (38.24) 56.7 (48.84) 73.3 (58.93) 16.7 (24.05) 43.9 (41.24)

25.0 (30.00) 11.7 (25.31) 23.3 (28.86) 38.3 (38.24) 20.0 (26.57) 63.3 (52.74) 30.3 (33.62)

58.9 (51.40) 54.5 (49.02) 43.7 (43.69) 59.2 (50.79) 36.4 (36.82) 32.0 (33.79)

* Mean of three replications (Values in parentheses are arc sine transformation) CD (P=0.05) Isolates = 4.28 Hosts = 12.77 Interaction = 17.43

in respect of infection between M. phaseolina and the crops belonging to Fabaceae, Pedaliaceae and Asteraceae might be attributed to the host nutrition (Raut and Ingle, 1989). However, Singh and Nene (1990) reported that in general M. phaseolina was non-specific, but the reason for higher aggressiveness on non-host was not clear. References Byadgi, A.S. and R.K. Hegde. 1985. Variation among the isolates of Rhizoctonia bataticola from different host plants. Indian Phytopath., 38 : 297-301. Diourte, M. 1987. Pathogenic variation and morphological studies of Macrophomina phaseolina (Tassi.) Goid. M.S. Thesis, Texas A & M. Univ., Texas, USA. Jones, R.W. and S. Canada. 1994. Electrophoretic karyotype analysis and mapping of an endogluconase gene from Macrophomina phaseolina. phytopathology, 84 : 1146 (Abstr.)

Manici, L.M., F. Caputo and C. Cerato. 1995. Temperature responses of isolates of Macrophomina phaseolina from different climatic regions of sunflower production in Italy. Plant Disease, 79 : 834-838. Pawar, M.N., B.B. More and P.G. Utikar. 1978. Host range of Macrophomina phaseolina. (Maubl.) Ashby inciting charcoal rot of sunflower. Food Farming and Agriculture. 10 : 20. Raut, J.G. and R.W. Ingle. 1989. Variations in isolates of Rhizoctonia bataticola. Indian Phytopath., 42: 506-508. Singh, S.K. and Y.L. Nene. 1990. Cross inoculation studies on Rhizoctonia bataticola isolates from different crops. Indian Phytopath. 43: 446-448. Singh, S.K., Y.L. Nene and M.V. Reddy. 1990. Addition to the host range of Macrophomina phaseolina Plant Disease, 74 : 828. (Received : November 2004; Revised : September 2005)