First report of Bipolaris sacchari causing wheat stem-base disease in Iran

M.J. Soleimani* and S. Kazemi

Dept. of Plant Protection, College of Agriculture, Bu-Ali Sina University, Hamadan, Iran

*agrms@basu.ac.ir

Accepted for publication 26/04/05

During May and June of 2003, wheat plants in several fields in Hamada, Iran showed symptoms of root rot and crown necrosis. Stem-base and root samples were submerged in 0.5% sodium hypochlorite for 3-5 min., rinsed with sterile distilled water, transferred to Petri dishes containing PDA, and incubated at 22-25°C for 1 week. Bipolaris spp. was the most prevalent fungus isolated. Based on the host origin, conidia and conidiophore morphology, number of pseudosepta and hilum characteristics, the pathogen was identified Bipolaris sacchari (Sivanesan, 1987).

Inoculum for pathogenicity tests was produced by seeding 200 g of sterile wheat stubble in an Erlenmeyer flask with four 5-mm diameter mycelial plugs from 5-day old fungal colonies grown on agar medium, and incubating at room temperature for 3 weeks. The inoculated wheat straw was incorporated into sterile soil (1% w/w), then transferred to five 25-cm pots and planted with 8 wheat seeds per pot. Control plants were grown in soil containing 1 % sterile wheat straw. The treatments were replicated five times. Plants were grown in a greenhouse for 75 days at 24°C, then scored for disease (Singleton et al, 1992). Symptoms were similar to those observed in the field and no disease was found in the control plants. The fungus was re-isolated from the infected parts. In a separate study using wheat cultivars ‘Alvand’ and ‘Roushan’, the pathogen caused a significant reduction on seed germination and plant height.

To our knowledge, this is the first detailed report of root and stem rot disease of wheat caused by B. sacchari in Iran. Further field studies are needed on the ecology and pathogenicity of B. sacchari to formulate steps for controlling root and stem rot of wheat.

Acknowledgment

Financial support for this work by the Research Council of Bu-Ali Sina University, Hamadan, Iran, is gratefully acknowledged.

References

Singleton LL, Mihail JD, Rush CM, 1992. Methods for Research on Soil-borne Phytopathogenic Fungi. St Paul, MN., USA: APS Press.

Sivanesan A, 1987. Graminicolus Species of Bipolaris, Curvularia, Drechslera, Exserohilum and their teleomorphs. Mycological Paper No 158, Wallingford, UK: CAB International.

The British Society for Plant Pathology