Effect of Resistance on Growth ofCercospora beticolaRace C2 on the Leaf Surface and within Leaf Tissue of Sugar Beet

Publisher Website
Google Scholar
Abstract
When the open-pollinated sugar beet cultivar FC 701/2 was inoculated with C. beticola, race C2, individual plants responded with a susceptible reaction, a large fleck reaction, a small fleck reaction or no visible reaction. For a given plant, these symptoms were consistent from 1 time of inoculation to another. On resistant plants, the number of germ tubes per conidium, width of mycelium, and appressorium length were reduced and the appressorium configuration was altered, compared to those parameters on susceptible plants. These changes were a fungal response to the resistance of the plants rather than an environmental effect. Histopathological studies showed that, although not usually visible to the unaided eye, necrosis of host tissue was present at or near the site of hyphal penetration .apprx. 1/3 the depth of the leaf thickness. The amount of necrosis was similar in the large and small fleck host response. The hyphae within the resistant host were usually limited to a single mycelium with 1 or 2 branches, while in the susceptible hosts a dense stroma developed in the necrotic tissue. Chloroplasts, nuclei and nucleoli degenerated in infected cells near hyphae compared with those from healthy cells.

This publication has 1 reference indexed in Scilit: