Lignin Content and Resistance to Sclerotinia minor in Peanut

Abstract

ABSTRACT Lignin has been shown to be an important component for plant defense in several pathosystems, but the relationship between peanut stem lignin content and resistance in the field to Sclerotinia blight has not been investigated. Stem lignin was quantified from twenty runner, six virginia, and ten spanish genotypes grown in the greenhouse using the acetyl bromide method. Significant differences in lignin content were found within the runner and spanish entries, but not among the virginia genotypes. Disease data collected in the field over two to three years were used to test correlations between lignin content and Sclerotinia blight resistance for a subset of the runner and virginia entries. No significant correlations were found. Within the runner entries, the highest and lowest stem lignin content was found in entries with the most disease resistance. These results indicate that preformed stem lignin content is not a reliable predictor for resistance to Sclerotinia blight in peanut. In addition, commercial peanut cultivars appear to vary considerably in lignin content, and the genotypes with lower levels of stem lignin may be useful to producers who can use peanut haulm for animal feed. Southwest Runner, a cultivar with high resistance to Sclerotinia blight, had the lowest stem lignin content of the 36 peanut lines tested.