LONG TERM AND LEAST EXPENSIVE PRESERVATION METHODS FOR VARIOUS FUNGAL CULTURES

A comparative study was conducted on long-term fungal culture preservation methods. A total of eight species (112 isolates) of phytopathogenic fungi ( Alternaria alternata , Alternaria solani , Fusarium oxysporum f. sp. lentis , Fusarium oxysporum f . sp . capsici , Rhizoctonia solani , Lasiodiplodia theobroma e, Colletotrichum gloeosporioides and Curvularia lunata ) belonging to six genera were stored up to 2 years by using five preservation methods (silica gel, cereal grains, mineral oil, soil and distilled water) and their viability was tested periodically after 6, 12, 18 and 24 months. The morphological characters viz. colony diameter, color, texture, topography and sporulation was studied. Each plant pathogenic isolate was considered as viable if morphology of culture was same to the original culture and comparable with the identification keys documented for fungi. Fungal cultures preserved on silica gel had maintained the highest viability as compared to other methods overall. Preservation using soil, and cereal grains was recognized as good storage method. However distilled water and mineral oil storage of some of the preserved cultures showed the least viability after eighteen months. The highest revival percentages after 24 months of preservation for A. alternata and A. solani was by sterile soil (90% and 83.3% respectively), F. oxysporum f. sp. lentis and F. oxysporum f . sp . capsici  (93.3% and 92.8% respectively), L. theobromae (77%) and C. lunata (63.6%) by silica gel preservation, R. solani (88.8%) and C. gloeosporioides (85%) by cereal grains. The above least expensive and long term methods for fungal preservation are beneficial for laboratories that have limited resources.