Resistance in sweetpotato to the scurf and black rot pathogens

Abstract

Over 600 sweetpotatoes (Ipomoea halalas (L.) Lam.) were evaluated for resistance to black rot (Ceratocystis fimbriata Ell. & Halst.) and 506 to scurf (Monilochaetes infuscans Eli. & Halst.). Vine cuttings from the varieties were inoculated to initially evaluate disease resistance to both fungi. From the3e tests approximately 8% of the varieties were selected for re:;istance to black rot and 7% for resistance to scurf. Enlarged roots of these varieties were inoculated with the respective pathogens, and lesion diameter after incubation was the criterion for measuring resistance. No variety was immune from eithcr pathogen. For both diseases, varieties selected from the vine cutting inoculations developed symptoms in their inoculated roots ranging from rcsistant to very susceptible; and there was no correlation between the disease reaction expressed by vine cuttings and that by roots of the varieties. Most varieties with superior resistance in their enlarged roots to either scurf or black rot came from South America.

Additional information

Notes on contributors

L. W. Nielsen

Fulbright Research Grantee; contribution from the Department of Plant Pathology, North Carolina Agricultural Experiment Station, Raleigh. North Carolina. U.S.A.