ISOLATION AND CHARACTERIZATION OF Bacillus subtilis (Cohn) FOR BIOEFFICACY AND GROWTH PROMOTION AGAINST DISEASES OF CHILLI (Capsicum annuum L.)
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Date
2016-06-30
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UNIVERSITY OF AGRICULTURAL SCIENCES, RAICHUR
Abstract
Bacillus subtilis an endospore forming, gram positive bacteria, plays a major role in biocontrol and PGPR activities. In the present investigations evaluated the B. subtilis isolates were evaluated for bioefficacy and plant growth promotion against major pathogens of chilli. Thirty isolates were collected from rhizosphere samples from different parts of North Eastern Karnataka. All the isolates showed positive for gram reaction, endospore, oxidase, catalase, starch hydrolysis, negative for indole, KOH test and green coloured colonies on Hichrome Bacillus agar medium. Among thirty isolates, 17 of them were positive for HCN, 24 for H2S, 23 for NH3 and 23 for IAA positive. 16S rRNA sequence analysis confirmed that all isolates belonged to B. subtilis. Among different B. subtilis isolates BS16 showed maximum inhibition of mycelial growth of F. solani (65.27 %), R. solani (46.58 %), S. rolfsii (64.04 %), C. capsici (63.42 %), BS22 for A. flavus (40.96 %) compared to control. The isolate, BS16 recorded highest germination (94.25 %), vigour index (1030), shoot length (8.50 cm) and root length (4.8 cm) compared to control. The treatment BS16+FS recorded higher peroxidise (PO) (1.04 change in absorbance at 470 nm/min/mg protein), polyphenol oxidise (PPO) (0.79 change in absorbance at 420 nm/min/mg protein) and Phenyl alanine ammonia lyase (PAL) (182.74 nmol trans-cinamic acid/hr/mg protein) activity on the 7th day after challenge inoculation, thereafter the activity declined by 9th day. The treatment BS16+FS showed highest activity of PO (1.82 change in absorbance at 470 nm/min/mg protein), PPO (1.93 change in absorbance at 470 nm/min/mg protein) and PAL (80.45 nmol trans-cinamic acid/hr/mg protein) on 30th day after challenge inoculation and thereafter these enzyme activity started decreasing on 60th and 90th day. Among various carrier materials used for the formulation, the cfu was maximum in talc powder (1.8×108 cfu/g) and least was in case of rice bran + husk (1.08×108 cfu/g) up to six months. Among six fungicides Carbendazium 50 WP showed compatibility with B. subtilis (Bs 16) by least zone of inhibition (15 mm at 0.3 %) and (Tricyclazole 18 % + Mancozeb 62 %) showed incompatibility with highest zone of inhibition (23.06 mm).
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