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Subject: Plant Pathology × Author: Amirtha Lingam. V × End date: 2022 × Start date: 2020 × Type: Thesis ×
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    ThesisItemOpen Access
    Development of microbial consortia for f the management of chickpea wilt caused by Fusarium oxysporum.sp. ciceris
    (G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145, 2022-10) Amirtha Lingam. V; Tewari, A.K.
    Chickpea wilt caused by F. oxysporum f.sp ciceris is one of the most devastating disease of chickpea in India and all over the world, this pathogen can cause yield losses up to 10-94 per cent depending on inoculum and environmental conditions. Use of chemical fungicides could not effectively manage this disease due to its soil borne nature. The pathogen survives in soil up to 6 years in the form of chlamydospores as a source of primary inoculum. Presently, single microbe-based biocontrol strategies are used for plant disease management. Inconsistent performance of single antagonists can be related to limited competition in the soil microbiome. In view of above present study “Development of microbial consortia for the management of chickpea wilt caused by Fusarium oxysporum f. sp. ciceris” was undertaken. During the Rabi season (2017-18), chickpea plants showed wilt symptoms were collected, isolated and identified up to molecular level as Fusarium oxysporum f.sp. ciceris. Fungal and bacterial antagonists (T.asperellum strains Th-14, Th-17, Th-19 and TCMS 36 and P. fluorescens strains Psf-2, and Psf-173) recommended for the management of chickpea wilt pathogen were selected for the consortia study. Antagonists were prepared in 14 different combinations and compatibility was checked by three methods and in all the methods it has been observed that all the consortia combinations were found compatible with each other. Antagonism action of consortia against pathogen was also studied using three different methods. In dual culture (mycoparasitism) study Th14+TCMS36 showed 61 per cent mycelial parasitization. In paired plate technique effect of volatile compounds of Th14+Psf173 showed significant maximum mycelial inhibition (66.67%). In cell free culture method the effect of non- volatile compounds of Th14+Psf173 showed maximum mycelial growth inhibition (74.81%). In glasshouse studies Th17+Psf173 and TCMS36+Psf173 were showed maximum per cent seed germination (96.67 % in each) with minimum pre-emergence mortality (3.33% in each) as compared to control (71.67% & 28.33% respectively) at 07 DAS. At 60 DAS, Th14+Psf173 showed minimum wilt incidence (6.84%) as compared to control (58.25%) and maximum wilt reduction (88.25%) over control and was at par with TCMS36+Psf173 (8.60% & 85.39 % respectively). Th14+Psf173 showed maximum vigor index (4783.17) followed by TCMS36+Psf173 (4505.67) as compared to control (2603). In field experiment pooled data revealed that Th14+Psf173 showed maximum per cent seed germination (84.80%) followed by Th17+Psf173 (83.27%) and TCMS36+Psf173 (82.93%) as compared to control (69.13%). At 120 DAS maximum wilt disease reduction was observed in Th14+Psf173 (88.54%) followed by TCMS36+ Psf173 (84.55%). Maximum mean yield was recorded in Th14+Psf174 (17.30 q/ha) followed by TCMS 36+Psf173 (16.47q/ha) and Th17+Psf173 (15.26 q/ha) as compared to control (8.05 q/ha). Consortia Th14+Psf173 and TCMS36+Psf173 were found significantly better in the induction of defence related enzymes/ compounds (Peroxidase, polyphenol oxidase, Phenylalanine ammonia lyase, Total Phenolic Content, and Superoxide dismutase) against chickpea wilt disease in glasshouse and in field.Population dynamics of antagonists were increased upto 50 DAS and it was maximum in Th14+Psf173 (22.33 & 12.67 ×104 cfu/g respectively) followed byTCMS36 + Psf173 (19.33 & 11.00 ×104 cfu/g respectively). Thereafter, population were declined till the last date of observation (125 DAS Further best performed treatment were confirmed by re isolation and characterized up to molecular level. Based on cultural, morphological, biochemical and molecular characteristics the superior introduced consortia (Th14+Psaf173 and TCMS36+ Psf173) were re-isolated and confirmed that Th14, TCMS36 and Psf173 have similar matching characteristics as of their mother culture. These findings revealed that potential introduced antagonists survived in the rhizosphere of chickpea plant instead of native strains. On the basis of present studies these two consortia could be recommended for the cost effective, ecofriendly management of chickpea wilt disease.