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ABSTRACT
Tomato (Lycopersicon exculentum L.) is a popular vegetable widely grown in the tropics, wthich is mainly attacked by Fusarium wilt incited by Fusarium oxysporum f sp. lycopersici. In this present scenario, ecofriendly alternative strategies such as use of fungi from rhizosphere and endophytic bacteria are being explored. Fungal antagonistic Trichoderma spp. are effective for the management of soil borne plant pathogens. Efficacy of various isolates of T.virens were evaluated under green house condition for efficacy in suppressing incidence of Fusarium wilt disease and promoting plant growth in tomato. Among the various isolates tested, native isolates of T.virens (Tv1) increased the plant growth and highly inhibited the mycelial growth of the pathogen under in vitro condition. In green house studies seed treatment plus soil application of talc based formulation of T.virens (Tv1) significantly reduced incidence of the diseases (54.66% more efficient than control), compared to the other isolates of T.virens. Expression of various defence related enzymes was found involved in the induction of systemic resistance against pathogen infection. Tomato plants treated with seed @ 4gkg-1 plus soil application of 4kg ha-1 of talc based formulation of T. virens (Tv1) with challenge inoculation of Fusarium enhance the maximum induction of defense enzyme such as Peroxidase (PO), Polyphenol Oxidase (PPO) and Phenylalanine Ammonia Lyase (PAL) rather than the other isolates of T.virens. The enzyme activity increased from 7th day of sampling and the maximum was observed on 14th day of sampling and then it slightly decreased.
Key words: Defense enzyme, Trichoderma virens, Tomato.
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INTRODUCTION
Tomato (Lycopersican exculentum L.) is a popular vegetable widely grown in the tropics which is an excellent source of vitamin A and vitamin C, minerals like iron and phosphorus. In tropical Asia it is an important cash crop from small farmers (Villareal, 1979). It tops the list of industrial crops because of its outstanding processing quantities. Total area under tomato in India is about 3.56 lakhs hectare with an average yield of 15.7 tonnes per hectare. In Tamil Nadu the area under tomato cultivation is 21055 hectare with an average yield of 11.04 tonnes per hectare (Vakes and Singhal, 2005). The crop is affected by sever al fungal pathogens, of which F. oxysporum f sp. Lycopersici...