ARS | Publication request: A DETACHED-LEAF ASSAY FOR IDENTIFICATION OF WHEAT LINES RESISTANT TO STAGONOSPORA NODORUM BLOTCH

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2000
Publication Date: N/A

Technical Abstract: Eight winter wheat lines carrying different sources of resistance to Stagonospora nodorum and three lines historically observed as susceptible were tested using a detached-leaf assay. The basal portion of a leaf was cut to approx. 40 mm in length, inserted into agar containing 50 ppm benzimidazole and 250 ppm chloramphenicol, and inoculated with 2 ul (20,000 spores) of a 107 spores/ml suspension of pycnidiospores. Leaves were incubated at 20 C with a 12 h day/night cycle. Lesion area, area of chlorosis, latent period, and spores per lesion were measured after 10 days. Cultivars and lines historically observed as resistant in the field were consistently identified as resistant by the detached-leaf test, while those known to be susceptible in the field were susceptible by the detached-leaf assay. Latent period, the time from inoculation to production of spores, was less than 7 days for susceptible lines but varied from 11-15 days among those that were resistant. Resistant lines produced both the highest and lowest numbers of spores/lesion, while the most susceptible lines were intermediate.