Abstract
YEH, C. C., and J. B. SINCLAIR. 1980. Sporulation and variation in size of conidia and conidiophores among five isolates of Cercospora kikuchii. Plant Disease 64:373-374. The sporulation of five soybean (Glycine max) seed isolates of Cercospora kikuchii, causal fungus of purple seed stain of soybean--Ck-I (ATCC 36864), Ck-A, and Ck-B from Illinois, Ck-T from Taiwan, and PS-161 from Indiana-was compared on carrot leaf-decoction agar (CLDA), dead soybean plant tissue agar (DSPT), potato-dextrose agar (PDA), and V-8 juice agar (V-8A) at either alternating 12 hr of light and dark or continuous dark at 25 C. Lighting regimen, type of medium, and source of inoculum (mycelia or mycelia plus conidia) influenced spore production. All isolates produced conidia at 12 hr of alternating light and dark; production was sparse under continuous dark. More spores were produced by all isolates on CLDA, DSPT, and V-8A than on PDA. Conidia production was not significantly different among isolates on all media tested. Conidia and conidiophores of Ck-B were smaller than those of the other four isolates. The sizes of conidia and conidiophores varied within each isolate. It is suggested that inoculum of C. kikuchii for field inoculations be grown on V-8A, DSPT, or CLDA under alternating 12 hr of light and dark at 25 C and that the plates be inoculated by spreading mycelia plus conidia over the agar surface. The literature is confusing concerning the correct medium to use for the study of sporulation of Cercospora kikuchii (T. Matsumoto & Tomoyasu) Gardner, causal fungus of purple seed stain of soybean (Glycine max) (9). Crane and Crittenden (1) obtained only mycelial growth of C. kikuchii on potato-dextrose (PDA), Czapek, and Bacto agars. The isolate of C. kikuchii studied by Matsumoto and Tomoyasu (6) sporulated on raisin decoction agar but not on 13 other decotion agars or on three defined liquid media. Matsumoto (5) and Murakishi (7) claimed that the fungus would sporulate only on living host tissues. Kilpatrick and Johnson (3) and Lyda et al (4) induced sporulation of the fungus by using carrot leaf-decotion agar, but Vathakos and Walters (10,11) failed to verify their results. Roy and Abney (8) reported that their isolates of C. kikuchii sporulated on PDA and V-8 juice agar (V-8A), but Vathakos and Walters (10) could not obtain sporulation on these two media. However, Vathakos and Walters (10) obtained abundant conidia production on dead soybean plant tissue agar (10) and senescent soybean plant tissue (11) under alternating 8 hr of light and 16 hr of dark; conidia production under continuous dark was sparse. Lyda et al (4) obtained conidia production on V-8A in Supported in part by the Illinois Agriculture Experiment Station and U.S. Agency for International Development (AID) contract TA/C-1294. The views and interpretations are those of the authors and should not be attributed to AID or to any individual acting in its behalf.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call