SPORULATION OF DRECHSLERA-GRAMINEA ON BARLEY STRAW EXTRACT AGAR

A simple method was developed to induce sporulation in Drechslera gram inea. Thirty-six isolates of D. graminea, gathered from Canada, German y, Montana, and Syria, were cultured, developed vigorous colonies and produced abundant conidia. Sporulation of the fungus was induced using straw extract from the barley cultivars Arta, Bowman, Bracken, Clark, Gallatin, and Salmas. There were significant differences in sporulati on among isolates from different areas as well as among isolates origi nating from the same barley field. Incubating the culture plates at 16 C under fluorescent light (12 h light/l2 h dark) for 5 d following in cubation under near ultraviolet (NUV) light for 7 d resulted in 40% hi gher conidia production. Extract of seed, green straw or green leaves of barley as well as extract of mature wheat straw did not induce spor ulation in D. graminea in culture. Twenty-one of the 36 isolates produ ced pycnidia following the 7-day incubation under NUV light. Five of 2 5 isolates grown on V8-juice agar failed to sporulate. Germination of conidia of 12 isolates ranged from 72 to 99%.