Differences in the mode of penetration of soybean hypocotyls by two races of Phytophthora megasperma var. sojae
Keyword(s):
Penetration of soybean hypocotyls (Glycine max L. Merr.) cv. Mack following inoculation with zoospores of races 4 (compatible) and 6 (incompatible) of Phytophthora megasperma Drechs. var. sojae Hildeb. was compared with previous observations of penetration of cv. Altona, on which the compatibility of these two races is reversed. On both cultivars race 6 tended to penetrate preferentially between anticlinal walls of adjoining epidermal cells, while race 4 penetrated periclinal and anticlinal walls with almost equal frequency. Thus it appears that the mode of penetration by these two races is not influenced by the compatibility of the interaction but is a characteristic feature of each race.