Investigation, characterization and prevalence assessment of various fungalcontaminants in sugarcane in vitro cultures

Microbial contamination poses a significant challenge during the tissue culture process. The current investigation focuses on examining fungal contaminants in in vitro cultures of two distinct sugarcane varieties, CoN 13073 and CoN 707, aiming at their detection, isolation, and identification. The study employed the fungal tip isolation method to isolate and identify fungal contaminants. Six different fungal species were identified, including Aspergillus flavus Link, Penicillium sp., Macrophomina phaseolina (Tassi) Goid., Curvularia sp., Rhizopus sp., and an aseptate sterile fungus, based on their cultural and morphological characteristics from contaminated cultures of the two sugarcane varieties. The frequency of fungal contaminants associated with in vitro cultures of sugarcane was assessed in both varieties at 15-day intervals from explant inoculation to 60 days. Among the six isolates, A. flavus (21.62-33.33%) was the most prevalent across all time intervals in both varieties, followed by Penicillium sp. (14.81-31.58%), Curvularia sp. (0-26.32%), M. phaseolina (0-21.62%), and Rhizopus sp. (15-19.05%). The least frequent fungal contaminant observed was the aseptate sterile fungus (4.76-11.76%) at all time intervals in both varieties.