Introduction of causal agent fungus of rice stem rot in Giulan.
1995
Javan Nikkah M. | Elahinia S.A. | Padasht F. | Hajarude Gh. | Sharifi Tehrani A.
In July, 1994 samples of stems and sheaths presenting severe infection were collected from Langrude and Siahkal. They were cultured on PDA and separated after 48 hours in 27+-2C. Culture, fungus colony is white at first, later grey to black. After five days in 25+-2C culture is covered with colony and within six days sclerotia appeared. For sporulation, sclerotia were cultured in moist blotter paper and conidia and conidiophores appeared on surface of them under constant light and room condition after 12 days. Conidia usually falcare, often sigmoid, 3 septate, intermediate cells large and pale- brown, end cells small and pale, 52-76 x 10-14.5. Conidiophores erect, simple and sparsely branched, 130-460*4-5. According to the above description this fungus was identified as Nakataea sigmoidea (Cav.). Hara. Single- conidium isolates were crossed on Sacch's Agar and rice sterile stem segments in flake, perithecium appeared under constant light and room condition after 16 days. It is dark, globose with long neck. Asci long- cylindrical, colorless, 100-200* 15-17.5, contain 8 ascospores. Ascospores curved, 3 septate, 45-65 * 6.25*7.5, pale brown. It was identified as Magnaporthe salvinii (Catt.) Krause and Vebster. Pathogenicity was proved according to Kopch's postulates. Conidial and perfect state of this fungus are reported for the first time from Iran.
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