Field Evaluation of Arbuscular Mycorrhizal Fungi in the Management of Orobanche: A Parasitic Weed in Tobacco (Nicotiana tabacum L.)

An investigation was carried out to evaluate the methods of application of AMF cultures in the management of Orobanche viz., planting of pre colonized tobacco seedling; soil application and the combination of both. The experiment was carried out in Orobanche infested soils of tobacco growing areas of Belagavi district. The results of the present investigations have revealed that the treatment received STD AMF had reduced the emergence of Orobanche (1.33 plot-1) compared to UASDAMFT (1.67 plot-1) and UASDAMFS (2.89 plot-1). The results with respect to different methods of applications of AMF on Orobanche numbers revealed that planting of pre colonized tobacco seedling plus soil application at the time of planting suppressed the Orobanche emergence (0.00 plot-1) compared to planting of pre colonized seedlings (1.67 plot-1) and direct soil application of AMF cultures at the time of planting (4.22 plot-1).The results pertaining to the interactive effect between mycorrhizal cultures in conjunction with the methods of application of AMF cultures significantly reduced the population of Orobanche with the treatment received planting of pre colonized seedling along with soil application of UASDAMFT, UASDAMFS and STD AMF recorded zero emergences of Orobanche at 60 DAP. However, the highest numbers of weeds were recorded in uninoculated control (68.67plot-1). Furthermore, mycorrhizal parameters like spore count and percent of root colonization were found to be the highest in the plots received mycorrhization in the form of pre-colonization and soil application with STD AMF at the time of transplanting in the main field compared to uninoculated control.