Screening of <i>Asparagus</i> species for resistance to <i>Stemphylium</i> leaf spot

Abstract

Abstract Fourteen taxa of the genus Asparagus were screened for their resistance to Stemphylium leaf spot under controlled conditions in growth chambers. The plants were inoculated with a conidial suspension of 2 isolates of Stemphylium sp. from asparagus. Disease assessment, based on percentage stem area necrotic, was made 13–17 days after inoculation. A. officinalis L. var. pseudoscaber (Grec.) Asch. &amp; Graebn. and the 2 cultivars of A. officinalis L., Rutgers Beacon and Mary Washington, showed high levels of infection. Most other taxa showed low levels of infection. Seven of these were classed as highly resistant: A. asparagoides (L.) W.F. Wight, A. compactus Salter, A. densiflorus (Kunth) Jessop cv. Myers, A. densiflorus (Kunth) Jessop cv. Sprengeri, A. larcinus Burch., A. verticillatus L., and A. virgatus Bak. These species are considered to be potential sources of resistance for breeding commercial cultivars resistant to Stemphylium leaf spot.