The effect of carbon concentration and carbon-to-nitrogen ratio (C:N) as well as their interaction on Colletotrichum coccodes growth and sporulation in submerged flask culture were evaluated. When C:N ratios were held constant, both mycelial dry biomass and spore yield increased with increasing carbon concentration. The specific spore yields (spore yield g−1 carbon), however, were not significantly different for the same C:N ratio in most cases. The highest spore yields (1.3 × 108 spores per ml) were obtained from media containing 20 g per liter carbon with C:N ratios ranging from 5:1 to 10:1. When the C:N ratio was greater than 15:1, spore yields were significantly decreased with increasing C:N ratios. High carbon concentration (20 g L−1) combined with high C:N ratios (above 15:1) reduced both mycelial growth and sporulation, and increased spore matrix production. Spores produced in medium containing 10 g L−1 carbon with C:N ratios from 10:1 to 15:1 had 90% germination on potato dextrose agar after 12 h and caused extensive shoot dry weight reduction on the target weed, velvetleaf. These results suggest that C:N ratios from 10:1 to 15:1 are optimal for C. coccodes spore production.
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Received 9 December 1997/ Accepted in revised form 22 May 1998
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Yu, X., Hallett, S., Sheppard, J. et al. Effects of carbon concentration and carbon-to-nitrogen ratio on growth, conidiation, spore germination and efficacy of the potential bioherbicide Colletotrichum coccodes . J Ind Microbiol Biotech 20, 333–338 (1998). https://doi.org/10.1038/sj.jim.2900534
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DOI: https://doi.org/10.1038/sj.jim.2900534