Mycoflora of postharvest rots of bitter yam Dioscorea dumentorum Pax in Nsukka agro ecological zone, Nigeria

This study was done to recover fungi associated with postharvest rotting of bitter yam, Dioscorea dumentorum tubers in Nsukka Agroecological Zone, Nigeria. Tubers showing signs of rot were picked from farmers in four randomly selected towns in the zone. The towns included, Nsukka, Orba, Ibagwa and Obollo-Afor. Five (5) samples each were picked from three (3) randomly selected farmers. Samples were packaged in sterile polythene bags, labeled accordingly and moved to the laboratory for studies. The fungal isolates were identified using both cultural and molecular techniques. Results showed that mycoflora of rotted bitter yams in the Zone were, Aspergillus flavus, Aspergillus niger, Lasiodiplodia pseudotheobromae, Galactomyces candidum and Rhizopus delemar. The percentage frequencies of occurrence of the fungal organisms ranged from 14.03% to 26% with A. niger recording the highest (26%) while A. flavus recorded the least (14.03%). Pathogenicity tests revealed that the fungi produced rots (diameter) ranging from 1.70 cm to 2.40 cm with R. delemar recording the highest rot diameter (2.40 cm) while A. niger produced the least (1.70 cm)Keywords: Bitter yam, mycoflora, postharvest, fungal organisms, Nsukka, rot