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Anand Agricultural University, Anand

Anand Agricultural University (AAU) was established in 2004 at Anand with the support of the Government of Gujarat, Act No.(Guj 5 of 2004) dated April 29, 2004. Caved out of the erstwhile Gujarat Agricultural University (GAU), the dream institution of Sardar Vallabhbhai Patel and Dr. K. M. Munshi, the AAU was set up to provide support to the farming community in three facets namely education, research and extension activities in Agriculture, Horticulture Engineering, product Processing and Home Science. At present there seven Colleges, seventeen Research Centers and six Extension Education Institute working in nine districts of Gujarat namely Ahmedabad, Anand, Dahod, Kheda, Panchmahal, Vadodara, Mahisagar, Botad and Chhotaudepur AAU's activities have expanded to span newer commodity sectors such as soil health card, bio-diesel, medicinal plants apart from the mandatory ones like rice, maize, tobacco, vegetable crops, fruit crops, forage crops, animal breeding, nutrition and dairy products etc. the core of AAU's operating philosophy however, continues to create the partnership between the rural people and committed academic as the basic for sustainable rural development. In pursuing its various programmes AAU's overall mission is to promote sustainable growth and economic independence in rural society. AAU aims to do this through education, research and extension education. Thus, AAU works towards the empowerment of the farmers.

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Subject: Plant Pathology × Author: Bagul, Mahendra Madhukar × End date: 2009 × Start date: 2000 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    BROWN LEAF SPOT OF BIDI TOBACCO CAUSED BY ALTERNARIA ALTERNATA (FRIES) KEISSLER AND ITS MANAGEMENT
    (AAU, Anand, 2001) Bagul, Mahendra Madhukar; Patel, J. G.
    Tobacco (Nicotiana tabacum L.) is an important cash crop. It is being extensively cultivated in more than 120 countries including India. India stand 2nd in area, 3rd in production and 6th in exports in world. It is not only important to growers but equally important to national economy by contributing excise revenue, earning foreign exchange and generating the employment. Brown leaf spot is an economically important disease of bidi tobacco caused by Alternaria alternata (Fr.) Keissler. The pathogen is soil and seedbome. It causes losses upto 36 %, in addition to considerable loss in quality of tobacco. Present investigations were carried out on isolation; pathogenicity, identification, survival, morphological and physiological characters, detection of pathogen in seeds of tobacco cultivars, in vitro and in vivo evaluation of phytoextracts, agrochemicals and bioagents against A. alternata, effect of weather parameters on disease and effect of disease on quality constituent of tobacco leaf at Bidi Tobacco Research Station, GAU, Anand Campus, Anand. During survey in Kharif-Rabi 1999-2000, it was observed that the brown leaf spot of bidi tobacco normally appeared in late of Nov. or early Dec. and increases continuously till the harvesting. Infected plants showed typical disease symptoms on leaves i.e. small water soaked circular spots, and became brown. Diseased leaves were collected from brown spot infected field, and pathogen was isolated from such diseased leaves and purified. The pure culture so obtained was used to prove the pathogenicity by artificial inoculation on tobacco plants of cultivar A-119 and GC-1. Fungal growth was light green in early stage and became grayish-black later. Germinated and ungerminated conidia of A. alternata were minute yellowbrown to medium golden-brown in colom. The length of conidia was 14.6 to 32.30 µm (av. 23.45µm) and width was 4.6 to 10.12 jiun (av. 7.36µm) along with 3 -5 and 0 - 3 horizontal and vertical cross-septa. Conidiophores were of 9 - 42.50 x 3 - 7 µm length and width. Long chain of conidia were observed in naturally infected leaves. The periodic isolation done from infected leaves on PDA medium revealed that pathogen could survive on plant debris beyond six months. In physiological study, of seventeen solid media tested, significantly highest colony growth of fungus (74.00 mm) was recorded after 7 days of incubation on Apple dextrose agar, followed by Host green leaf decoction agar. Tomato, Carrot and Potato dextrose agar media and showed 69.33 to 72.66 mm growth with good to excellent sporulation. In case of liquid media, maximum dry mycelial weight with excellent sporulation after 15 days of incubation was recorded on Richard's medium, Tomato and Carrot dextrose broth ie. 541.67, 535.00 and 465.00 mg 50 ml-1 medium, respectively. A. alternata grew well at wide range of temperature (10 - 45 °C) on Richard's medium, but the significantly highest dry mycehal weight (400.03 mg) with excellent sporulation was recorded at 30 °C and it was considered to be optimum temperature. Detection of A. alternata in seeds of different tobacco cultivars representing various areas of Anand district, seeds of (A-119) Asodar showed more per cent infection of A. alternata i.e. 15-18 in sterilized seeds and 19 - 23 in 19 - 23 in in sterilized seeds as compared to seeds of cultivars i.e. A-2, GT-5 and GT-7. From this study, it was also noticed that Standard blotter method recorded higher count of test pathogen than the Agar plate method. Out of forty eight aqueous phytoextracts screened @ 5, 10 and 20 % in vitro, irrespective to concentrations extracts of Acacia arabica, Ocimum sanctum, Lawasonia inermis. Eucalyptus globulus, Emblica officinalis were found more effective in inhibiting the growth oi A. alternata to the extent of 58.87 - 65.99 per cent. Phytoextracts of A. arabica, O. sanctum, L. inermis, Azadirachta indica and Pongqmia glabra showed 66.66 - 77.31 per cent inhibition of fungal growth at 20 %. Similarly at lower concentrations i.e. 5 and 10 % found effective inhibition i.e. 48.61 - 65.75 per cent in extracts of A. arabica, L inermis, O: sanctum, E. gloubulus, E. officinalis, F. religiosa, Syzygium cumini, Tamarindus indica and A. indica. On the other hand extract of S. cumini (seeds) favoured the growth of test fungus. Out of eighteen fungicides, Mancozeb was found most effective at 1000, 2000 and 4000 ppm and completely inhibited (100 %) the fungu growth. Similarly complete inhibition of fungal growth was also observed at higher concentrations in case of Propiconazole @ 700 and 1400 ppm, Penconazole @ 700 and 1400 ppm. Octave @ 500 and 1000 ppm, Hexaconazole @ 200 ppm and Copper oxychloride @ 4000 ppm. These fungicides and Difenconazole at lower concentrations were found effective in inhibiting the fungus growth to the extent of 80.00 to 95.40 per cent. Deitamethrin, Monocrotophos and Dichlorovos were found effective insecticides at 200, 1000 and 1000 ppm and showed high fungicidal efficacy with complete inhibition of the mycelial growth of A. alternata.