Skip to main content
ARS Home » Research » Publications at this Location » Publication #113966
Title: EVALUATION OF FOUR TYPES OF SCLEROTINIA MINOR INOCULA TO DIFFERENTIATE THE REACTION OF PEANUT GENOTYPES TO SCLEROTINIA BLIGHT

Author
item FASKE, TRAVIS - OKLAHOMA STATE UNIVERSITY
item Melouk, Hassan
item PAYTON, MARK - OKLAHOMA STATE UNIVERSITY

Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/11/2000
Publication Date: 12/1/2000
Citation: N/A

Interpretive Summary:

Technical Abstract: Greenhouse inoculation experiments were conducted with 5 runner peanut genotypes (Okrun, Southwest runner, TX 901338-2, TX 961738, TX 961678) using 4 types of inocula of Sclerotinia minor to determine their efficacy in differentiating disease response. Five- to six-week-old plants grown in 10-cm pots were used throughout the study. All but the terminal leaves were eremoved, leaving about 1 cm of each petiole on the main stem. The 4 inocul consisted of germinating sclerotia produced on peanut stem, 3-day-old dried mycelia, granules of perlite (2-3 mm) impregnated with fresh mycelial fragments, and mycelial plugs (5-mm diameter) taken from the periphery of a 2-day-old culture growing on potato dextrose agar containing 100 ug/ml streptomycin sulfate. Each inoculum was consistently placed between the stem and a petiole in the middle of the main stem. Inoculated plants were placed in polyethylene chambers (Peanut Sci. 19:58-62) on a greenhouse bench where day and night temperatures were 24+/-2 deg C and 19+/-2 deg C, respectively. Relative humidity was maintained at 95-100% by lining the bottom of the chamber with a wet towel and misting the sides with water. Length of lesion was recorded daily starting on the 3rd day through day 6, after inoculation. Length of lesion of the 6th day after inoculation for each inoculum type was useful in separating Okrun, a S. minor-susceptible genotype, from the moderately resistant runner genotypes. Rate of lesion expansions using germinating sclerotia, perlite inoculum and dried mycelia, over genotypes, were significantly (P=0.05) less than mycelial agar plug, and were 10.3, 11.0, 10.1 and 15.2 for germinating sclerotia, dry mycelium, perlite inoculum, and mycelial plug, respectively.