Growth and sporulation of some Gnomonia leptostyla isolates in various culture media

Walnut anthracnose is the most common disease in common walnut, Juglans regia L., in Iran, caused by Gnomonia leptostyla. In current research, efficiency of various culture media including BAB, OMA, MA, NA, PDA, CMA, WLEA and WLEOMA in growth and sporulation of the fungus were studied. Three contaminated leaf samples from Miyaneh (No), Marand (DV) and Karaj (Md) areas were selected and after fungus isolation, they were cultured on mentioned media with three replications. Cultures were incubated in oC, 50% RH and: (L:D) photoperiod and some traits such as maximal colony diameter, colony pattern, mycelium density, sexual and asexual reproduction were investigated after, , 6, 9, 4 and days. For perithecia maturation, primordial perithecia consisted cultures were incubated in 4oC in darkness for months. There was no significant difference between isolates in morphology, color and growth pattern, but in growth rates and sporulation. Md produced primordial perithecia on the culture without walnut leaf extract but the others were not able to do. No could not sporulate on PDA, WA, CMA and OMA media as much as other isolates. However all isolates could produce immature perithecia and acervuli on WLEA and WLEOMA. The weakest media was BAB and the most suitable media for fungus isolation was WA. Fungus growth rate was in maximum on OMA and the highest density of mycelium was obtained on PDA. Sexual and asexual reproduction has been occurred in best way on media with walnut leaf extract. However, any mature perithecia was not obtained in any culture after three month incubation.