STUDIES ON VARIABILITY IN THE ANTAGONISTIC POTENTIAL OF TRICHODERMA ISOLATES
KrishiKosh
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Title |
STUDIES ON VARIABILITY IN THE ANTAGONISTIC POTENTIAL OF TRICHODERMA ISOLATES
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Creator |
PARVATHI DEVI, Y
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Contributor |
ANIL KUMAR, P
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Subject |
nitrogen, fungi, yields, potatoes, planting, statistical methods, sowing, developmental stages, fertilizers, land resources
ANTAGONISTIC, TRICHODERMA ISOLATES |
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Description |
In the present study twenty six Trichoderma isolates comprising seven isolates of T. harzianum, eleven isolates of T. virens, two isolates of T. longibrachiatum and one isolate each of T. aureoviride, T. citrinoviride, T. piluliferum, T. polysporum, T. pseudokoningii and T. reesei were evaluated for their antagonistic potential against two soil borne plant pathogenic fungi, viz., Pythium aphanidermatum and Fusarium oxysporum f. sp. ciceri. Variability existed among the test Trichoderma isolates in antagonizing the test pathogen isolates. In case of Trichoderma - F. o. f. sp. ciceri interactions, five (19%) interactions resulted in static growth of both the interacting isolates, i.e., neither could overpower the other. Three out of twenty six interactions (12%) resulted in F. o. f. sp. ciceri overgrowing on Trichoderma. Remaining 69 per cent of Trichoderma isolates (18 out of 26 isolates) were found to be antagonistic to F. o. f. sp. ciceri. Eighty six per cent of T. harzianum isolates (six out of seven isolates) and 73 per cent of T. virens isolates (eight out of eleven isolates) were found antagonistic to F. o. f. sp. ciceri. In Trichoderma – P. aphanidermatum interactions, four per cent of the Trichoderma isolates were overgown by P. aphanidermatum (one out of twenty six), four per cent of the isolates of Trichoderma got lysed due to P. aphanidermatum (one out of twenty six), in 15 % of interactions both P. aphanidermatum and Trichoderma had static growth (four out of twenty six) and in 76 per cent of interactions (20 out of 26) Trichoderma overgrew P. aphanidermatum. Volatiles of F. o. f. sp. ciceri which enhanced the growth of Trichoderma isolates Ta, Tc, Th2, Th3, Tpil, Tpol1, Tv4 and Tv10 (60.9 to 8.6% increase in growth) Tv2, Tv3, Tv5, Tv8, Tv11 and Tv9 isolates growth was decreased (6.7 to 15.3% inhibition). Among the different species of Trichoderma, T. virens was most inhibited (15.3%) by the volatiles of F. o. f. sp. ciceri. Thus growth of 31% of Trichoderma isolates was encouraged in the presence of F. o. f. sp. ciceri, whereas 23% of Trichoderma isolates showed decreased growth when paired with F. o. f. sp. ciceri up to two days after inoculation. On the other hand, except Th5, all other isolates of Trichoderma inhibited growth of F. o. f. sp. ciceri in paired plates. In 36 per cent of Trichoderma isolates growth retardation was observed due to the volatiles of P. aphanidermatum two days after inoculation and only in 4 per cent of the isolates (only in Tv1) growth promotion was observed. Remaining isolates had no impact. Thus the present investigation revealed that Trichoderma growth was better when paired with F. o. f. sp. ciceri (31% of isolates) than when paired with P. aphanidermatum (4% of isolates). Inhibition in the radial growth of F. o. f. sp. ciceri due to Trichoderma culture filtrates was observed in all the treatments only up to three days. Later on the reduction in F. o. f. sp. ciceri growth was nullified in six of the twenty six isolates (23%) whereas in the remaining twenty isolates (76%) reduction in growth was continued. The initial inhibitory effect on P. aphanidermatum was nullified upon continued incubation for another day as the growth in culture filtrate amended medium was on a par with check (9.0 cm) except in Th4 (5.6% inhibition) and Tv1 (24.4% inhibition) where inhibition in growth continued. When different isolates of Trichoderma were grown on test pathogenic mycelial growth as sole nutrient source, reduction in growth was observed to the extent of 70 to 98 per cent on F. o. f. sp. ciceri and 59 to 82 per cent on P. aphanidermatum in comparison to Czepek-Dox broth. When the fungal mycelium from the interaction zones was observed under microscope, none of the interactions involving F. o. f. sp. ciceri or P. aphanidermatum and the test Trichoderma isolates revealed mycoparasitic signs such as hyphal coiling and formation of appressoria. However, chlamydospore formation and granulation of cytoplasm were found prominent in Trichoderma–F. o. f. sp. ciceri interactions. In Pa-Trichoderma interactions, lysis of the mycelium, formation of primary septa just beneath the lytic portion, granulation and vacuolation of cytoplasm, bulging and rupture of hyphae were prominent. Soil treated with Th3 (2.5%) and Tv1 (1.0%) recorded significantly lower chickpea wilt incidence, i.e., gave maximum protection to chickpea seedlings with 94 and 98 per cent disease control respectively. Seeds treated with Tv4 and Tv3 (10 and 20% disease incidence respectively) offered maximum protection up to 22 days after sowing with disease control equivalent to 75 and 50 per cent respectively. None of the Trichoderma treatments (soil and seed treatment) were better than seed treatment with metalaxyl in protecting tobacco seedlings from damping off. |
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Date |
2016-06-03T14:19:20Z
2016-06-03T14:19:20Z 2011 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/66721
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Language |
en
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Relation |
D9028;
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Format |
application/pdf
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Publisher |
ACHARYA N. G. RANGA AGRICULTURAL UNIVERSITY
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