AbstractsEconomics

newline ABSTRACT newlineThe present study on occurrence and identification of arbuscular mycorrhizae in rhizosphere soils of some economically important crops and their inoculation for mass multiplication and enrichment of soil microbial population was carried out to ensure their status keeping in view climate change and environmental security. Survey was conducted in different agroclimatic zones of Himachal Pradesh in India to record arbuscular mycorrhizae in rhizosphere soil samples of different agricultural crops. Isolation of these fungi was made by wet sieving and decanting method while identification was carried out by morphology of their resting spores on the basis of standard keys and literature. Multiplication of monosporal cultures of AM fungi was made in roots of maize and fenugreek. The effect of AM fungal application was studied on soil microbial population especially Trichoderma species which are known for their growth promoting and biocontrol activities. Glomus, Acaulospora and Scutellospora population was found highest while Gigaspora population was maximum in very high hills. The spore abundance was investigated to be a good indicator of a soil s AMF potential. There has been a new record of AM fungi in rhizosphere soil of tested crops. The effect of AM fungi on rhizosphere microbiomic population has not been reported erstwhile. The population of AM fungi (54.8/100g soil) was found more in irrigated soils of apple orchards at Mashobra (Shimla) and Raison (Kullu) and their population was also found more in 20 years old plantation (83.2/100g soil) than 5-6 years old (43.6/100g soil). The spore density also differed significantly among plant species indicating uneven distribution of AMF spores in rhizosphere soil. Twenty Glomus species were recorded in rhizosphere soils of different agro climatic regions. These were Glomus caledonicum, G. geosporum, G. globiterum, G. gerdemannii, G. halonatus, G. flavisporum, G. intraradices, G. mosseae, G. dimorphicum, G. melanosporum, Glomus spp., G. tubaeforme, G. aggregatum, G. austral, G. macrocarpum, G. manihotene, G. fasciculatum, G. pansihalos, G. pallidum, G. reticulatum and G. maculosum. Sclerocystis rubiformis was also recorded during microbiomic investigation. Besides, other AM fungi viz., Acaulospora laevis, A. nicolsonii, A. gerdemannii, A. foveata, A. sporocarpia, A. spinosa, A. scrobiculata and A. elegans were also found associated. Scutellospora spp. viz., Scutellospora calospora, S. heterogama, S. weresubiae, S. fulgida, S. reticulate, S. alborosea, S. nigra, S. gilmorei, S. verrucosa and S. gregaria have also been recorded in soil samples. Highest colonization by AM fungi was found to occur in natural rhizosphere soil of apple (47%) followed by fenugreek (463%), litchi (42.3%) and maize (41.3%). Cauliflower, cabbage and potato, however, showed minimum per cent root colonization to an extent of 6 to 7 per cent. The mycorrhizal inoculation efficiency was found maximum in fenugreek and extent of MIE in different crops varied from 30-35.3 per cent. In…