Browsing by Author "Indu, P."

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    Distribution of Arbuscular Mycorrhizae Associated with Coconut and Arecanut Based Cropping Systems
    (2012) Ambili, K.; George V. Thomas; Indu, P.; Murali Gopal; Alka Gupta
    Mycorrhizal fungi are widespread in agricultural systems and are especially relevant for organic agriculture. A study was conducted to assess diversity in the arbuscular mycorrhizal (AM) fungi associated with coconut and arecanut intercropping systems of Kasaragod and Thiruvananthapuram districts of Kerala. Mycorrhizal parameters like spore density, root colonization, species richness, and relative occurrence of species were recorded. Coconut cropping system was found to be densely vegetated with diverse AM fungi, Glomus spp., Gigaspora spp., and Acaulospora spp. The diversity of fungal species was found to be maximum in the high density multiple species cropping system plot of CPCRI, Kasaragod with coconut as the main crop and banana, pepper as intercrops and least in farmers’ plot of Mogral Puthur, Kasaragod with arecanut as main crop and banana as the intercrop. A total of fourteen AM fungi were identified from coconut and arecanut intercropping systems. Glomus aggregatum, Funneliformis mosseae, and Rhizophagus fasiculatum were observed in both the cropping systems studied. Among the six edaphic factors analysed, an inverse relationship of mycorrhizal population with soil pH and soil phosphorous was observed. An abundance of P-solubilizers, fluorescent Pseudomonas spp., N-fixers, Bacillus spp., and Trichoderma spp. were observed in the rhizosphere, with Bacillus spp. showing the maximum association with AM fungi. The higher AMF colonization in coconut cropping system imply that the AM fungi colonization is primarily dependent on the host plant rather than the climatic/edaphic components of an area.
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    Isolation and identification of spore associated bacteria (SAB) from Glomus and Gigaspora spp. in coconut and arecanut based cropping systems
    (2012-08) Ambili, K.; George V. Thomas; Indu, P.; Viji, M.V.; Murali Gopal; Alka Gupta
    Arbuscular mycorrhizal symbiosis is exhibited by 80% of the terrestrial plants. The spores of arbuscular mycorrhizal fungi (AMF) form a unique microhabitat for the colonization by many species of bacteria. The present study was undertaken to isolate and identify spore associated bacteria (SAB) and evaluate their functional role in AMF-host interactions with respect to germination of spores. Coconut and arecanut based cropping systems under organic management practices in farmer’s field in Kasaragod district, Kerala and high density multi species cropping system (HDMSCS), CPCRI farm were selected for the study. The results revealed that AMF spore load of a particular cropping system increase with the number of intercrops. Spore associated bacteria (SAB) were isolated from the cytoplasm of surface sterilized spores of Glomus and Gigaspora spp. Identification based on BIOLOG and 16S rRNA sequencing revealed the presence of bacteria - Citrobacter amalonaticus, Staphylococcus arlettae, Bacillus subtilis, Bacillus amyloliquefaciens, in association with spores of Glomus spp. Corynebacterium coyleae, Bacillus cereus and Bacillus subtilis were found to be associated with Gigaspora spp. In vitro studies to determine the germination potential in spores showed the maximum results with Bacillus cereus GiPHD1 and Citrobacter amalonaticus GLNCB1 with 40% increase over control.
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