Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/11/1997
Publication Date: N/A
Technical Abstract: All leaves except the top two on detached shoots (12-15 cm) from 8-wk-old peanut plants were removed. Four shoots were placed in a water-moistened 10 x 3.3 cm bag made of dialysis tubing (MWCO 12,000), which was placed in a foam cup (177 ml ca.) filled with 15 g perlite. One hundred ml of fragmented Sclerotinia minor mycelial suspension (containing 1 g mycelia) was added to each cup. Glass test tubes (1 x 14 cm) were each placed in a dialysis bag as controls. Dialysis bags and contents were lifted from the perlite medium after 5 days, and the outer surface facing the perlite was gently rinsed with cold running tap water. Ten 1-cm**2 squares were randomly cut from the dialysis membrane and placed on a glass slide with the inner surface of the membrane contacting the glass. The squares were stained with lactophenol cotton blue for 3 min, and mounted in glycerin gel. The number of infection cushions were counted using a light microscope. Two peanut genotypes and 13 isolates of S. minor were used. Over isolates in Okrun (a sclerotinia-susceptible peanut) an average of 4.5 infection cushions (IC)/cm**2 were formed, which was higher (p=0.05) than with the sclerotinia-resistant genotype Southwest Runner (2.7 IC/cm**2). These results suggest that quantifying IC formed on cellophane dialysis membrane in response to plant host contact could be sued to facilitate determination of reaction S. minor.