NSave Nature to Survive JURI DEVI, SADHANA MEDHI AND T. C. SARMA* Department of Botany, Gauhati University, Guwahati - 781 014 E mail: tarunchandrasarma@yahoo.com ABSTRACT A survey of indoor aeromycoflora of store houses of onion and ginger was carried out in Guwahati, Assam, during the period of March, 2009 to August, 2010, employing gravity slides and gravity petridish methods, with a view to correlating the decay of onion and ginger by the fungi in their stored conditions. This was being carried out in pursuance with some informal reports of the wholesellers regarding the spoilage of these two commercially important plant produce. Some microfungi were isolated belonging to the genera- Alternaria, Aspergillus, Botrytis, Cercospora, Colletotrichum, Curvularia, Cladosporim, Fusarium, Helminthosporium ,Lasiodiplodia, Mucor, Penicillium, Rhizopus, Trichoderma, Trichothecium, Verticillium. *Corresponding author 548
STUDY OF ONION AND GINGER INTRODUCTION Air is a natural medium for certain very very minute particles including many mycoflora. Investigations on the aeromycoflora were carried out in order to correlate with the different types of crop diseases in India viz.,diseases of banana, bajra, citrus, cotton, jowar, rice, sugarcane, wheat and other crops (Padmanabhan et al., 1953; Sreeramulu and Seshavataram, 1962; Sreeramulu, 1959; Sreeramulu and Ramalingam, 1963, 1964, 1965; Tilak and Kulkarni, 1970, 1972, 1980; Tiwari and Sahu, 1995). Occurrence of aeromycoflora in the fruit markets were also studied (Sarma and Bhattacharjee, 2001). Airborne mycoflora are largely determined by topography, meteorological parameters, vegetation and biotic factors including human activities (Lacey, 1981; Lyon et al., 1984). The mycoflora concentration in the atmosphere are influenced by the processes involved in their production, release and deposition (Lyon et al.,1984). The present study has been carried out to screen the mycoflora of air over the store houses of onion and ginger of Guwahati and to find correlation of occurrence and also the incidence of decay of both onion and ginger in the store houses. Onion is one of the most important vegetable crops. This important crop is being imported to Assam from different parts of India. Guwahati is the gateway of North-East India and it is also the commercial capital of N.E India. The imported onions are mostly stored in different storehouses of Guwahati and the varieties are- White onion. Red onion and Yellow onion. The fungal deterioration of all these varieties have been observed. Similarly rhizome of ginger which is also one of the most important spice crop of Assam are also stored in the different store houses of Guwahati. The important varieties of ginger in N.E India are- Bola, Moran and Jatia. There were some informal reports of the owners of the store houses that the decay of the rhizome of ginger in the stored conditions were severe. Keeping in view of this the investigations on the aeromycoflora and correlation with the decay of onion and ginger were carried out. MATERIALS AND METHODS Air samplings were carried out in different store houses of onion and ginger of Guwahati using gravity slides and gravity petridish methods. In the Czapek’s medium aliquiet of streptomycin was added to inhibit the bacterial growth. These petridishes were exposed to the air of different store houses at different duration such as 0, 1, 2 and 3 minutes; and at different heights -0- level(ground level) and 500 cms, 1000 cms and 2000cms above ground level. The experiments were done monthly for one year and 4 replicates were used for each sampling. The petridishes were incubated for 7 days. The isolates were examined and identified. For pathogenecity test a loopful of fungal mat was inoculated aseptically to healthy onion and ginger by making small incision in bulb and rhizome respectivily. The inoculated bulb and rhizome were kept wrapping in cellophane bags. The progress of spoilage were observed periodically. The data were correlated with meteorological parameters. RESULTS AND DISSCUSSION The mycoflora trapped from the air inside the store houses of onion and ginger were- Alternaria alternata, A. solani, Aspergillus flavus, A. niger, A. terreus, Cercospora sp., Cladosporium sp., Colletotrichum capsici, Curvularia lunata, Fusarium oxysporum, F. moniliforme, F. solani, F. zingiberi, Helminthosporium sp., Lasiodiplodia theobromae, Mucor mucedo, Penicillium citrinum, Rhizopus stolonifer, Trichoderma sp., Trichothecium sp. and Verticillium theobromae. Species of Alternaria, Colletotrichum ,Lasiodiplodia, Trichoderma and Trichothecium were not available at 1000cms and 2000cms. Petridishes containing media were exposed for 1 minute, 2 minutes and 3 minutes at different levels and accordingly microfungi were trapped. The fungal spores trapped at different levels and at different times have been shown in Table 1 and 2. The most predominant species found in air in store houses of onion were- Aspergillusniger, A. flavus, Botrytis sp., Fusarium oxysporum, Helminthosporium sp., Trichoderma sp. and Mucor mucedo. On the other 549
Change language