Evaluation of Asparagus officinalis L. germplasm for resistance to Stemphylium leaf spot

Abstract Asparagus officinalis L. accessions were screened for resistance to Stemphylium leaf spot under controlled environmental conditions. The plants were inoculated with a conidial suspension of two isolates of Stemphylium sp. from asparagus. Disease severity assessments, based on percentage stem area necrosis (% SAN), were made 13—17 days after inoculation. Estimates of mean % SAN ranged from 31 to 74%. None of the accessions showed outstanding levels of resistance, but significant differences were observed in disease susceptibility between accessions. The accessions also differed for within-accession variability. Selection for increased levels of resistance is likely to be most effective in accessions with high within-accession variance values.