Factors influencing the germination of macroconidia and secondary conidia of Claviceps africana

Abstract

The influences of temperature, time, and moisture on the germination of macroconidia and secondary conidia of Australian isolates of Claviceps africana were studied in vitro. The optimum temperature for germination of both macroconidia and secondary conidia of C. africana was 20°C. Although germination of macroconidia ceased near 31°C, approximately 30% of secondary conidia germinated at 37°C after 48 and 72 h of incubation. Sorghum flower extract agar stimulated macroconidium and secondary conidium germination, irrespective of temperature. Germination of macroconidia and secondary conidia on water agar started after 4 h of incubation at 20°C, reaching a maximum after 16–24 h and 14 h, respectively. Maximum germination of both macroconidia and secondary conidia was at ≥ –5 bars at 20°C. Germination of secondary conidia ceased at –35 bars, whereas macroconidia germinated at water potentials as low as –55 bars at 20°C.