PRASANNA KUMARI, V.KAVYA, NATI2022-08-172022-08-172022-08D6265https://krishikosh.egranth.ac.in/handle/1/5810186401MANAGEMENT OF SORGHUM TURCICUM LEAF BLIGHT USING BACTERIAL ENDOPHYTESThe present research on “Management of sorghum Turcicum leaf blight using bacterial endophytes” was carried out at the Department of Plant Pathology, Agricultural College, Bapatla. A total of 13 bacterial endophytes were isolated and designated based on the plant part from which they were isolated. Number of endophyte colonies was consistent in occurrence irrespective to the age of the leaf used for isolation, but was high from roots. The incubation period of 2.0 to 2.8 days was required for bacterial expression in sap inoculated samples. However it extended to 4.6 days with leaf bits. Morphologically most of the endophytes from the roots and leaf bits were round with few exceptions while most of the isolates from the leaf sap were irregular except SLSE-01 which was round in shape. Culture characters of the isolates had even to undulated colony margins with an exception with SLSE-05 to be lobate. Eight of the isolates were with raised colonies, while five isolates SLBE-02, 03, 05 and SLSE-01, 05 were flat. Most of the colonies had smooth texture with opaque nature except SRSE-02 and 03 which were translucent. Most of the isolates were creamy white while, SRSE-02, SRSE-03, SLBE-01 and SLSE-05 isolates were white colour and, SLBE-04 was cream coloured. Antagonistic studies revealed endophyte SRSE-01 with 52.75 % inhibition and was found significantly superior over other endophytes isolated from healthy leaf bits, root sap and leaf sap. SLSE-04 (51.65%), SLSE-05 (51.10%) and SLSE-03 (50.00%) isolates of leaf sap were found on par with each other and superior over endophytes from leaf bits. At interaction zone variation in growth pattern of fungus xiii with thickening of the hyphal strands (SRSE-01 and SLSE-02), anastomosis (SRSE-01, SLBE-02 and SLSE-05) and chlamydospores formation was observed. SRSE-01 was significantly superior over other isolates with high number of chlamydospores (222.67/ microscopic field) followed by SLSE-04 (135.33/ microscopic field) and SLSE-05 (117.67/ microscopic field) which were on par with each other. Lysis of the fungal mycelium was not observed in any of the interactions. In detached leaf technique all the isolates were superior over control in per cent spotted area, isolates SRSE-01 was found superior with minimum diseased area of 0.38 cm2 and with least per cent spotted area of 2.29% and was on par with SLSE-05 isolate (2.67%). No significant difference was observed among the isolates with respect to disease index. Based on the superior characters of SRSE-01, SLSE-04, SLSE-05 isolates in dual culture and detached leaf techniques, were advanced for other studies when found compatible with each other. All the three isolates tested positive for biochemical characters such as utilization of nitrogen sources, production of proteases, amylase and catalase whereas they failed to produce siderophore and IAA. SRSE-01 and SLSE-05 were found to solubilize phosphate indicating their ability in phosphate solubilization. Zone of solubilization around their colonies was more pronounced in SLSE-05 isolate compared to SRSE-01 isolate. Phenols content was found significantly high in the treatment where all the endophytes were simultaneously inoculated (2.06 mg g-1) compared to other treatments where endophytes are associated, however it was not superior over phenol from fungicide treated plants (2.29 mg g-1). Similarly, under green house conditions combination of all the three bacterial endophytes resulted in significantly high inhibition of disease (40.70%) at 64 DAS with minimum AUDPC value of 516.35 as against the control (739.53).EnglishThesis