Storage Life of Arbuscular Mycorrhizal Fungal (AMF) Inoculum in Vermiculite Based Culture

Arbuscular Mycorrhizal fungi (AMF) is ubiquitous soil borne fungi which provide an intimate link between soil and nutrient absorbing organs of plants. AMF fungi optimize the uptake of phosphorus in plant which results in increase in yield. Production of AMF inoculum and the storage in a viable condition for a longer period of time is still a serious constraint. This study describes the survival capability and infectivity of AMF spores under different storage conditions. The vermiculite based AMF inoculum contained spores of AMF namely Glomus sp., Gigaspora sp., Scutellospora sp., Entrophospora sp., and Acaulospora sp., identified from the rhizosphere soil collected from the maize crop cultivated at Mellur block of Madurai District in Tamil Nadu, India and the mixed AMF colonized host root bits as propagules. The AMF inoculum spore count was 5-6 / 100g inoculum and the infectivity was 100% in the roots of maize plant at the time of packing of the inoculum for storage. During storage, at the end of 180 days the AMF spore count was reduced to 2-5 / 100g inoculum and the infectivity was reduced to 90-95%. But the AMF inoculum stored with 10% moisture content at 20ºC - 30ºC and under the light intensity of 1500 lux maintained the same initial spore count of 5-6 / 100g inoculum and infectivity of 99% for the storage period of 150 days (5 months). The results of the present study suggest that AMF propagules, spores and hyphae colonized root bits in the form of vermiculite based culture maintained with 10% moisture content at temperature range of 20ºC - 30ºC and under light condition of 1500 lux for 5 months can be expected to be viable for infectivity in crop plants.