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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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ThesisItem Open Access MANAGEMENT OF LEAF CURL DISEASE OF TOMATO(2002) KRISHNAN, AMBILI; Valand, G. B.To evaluate the influence of various phytoextracts, chemicals and other substances against Tomato Leaf Curl Virus (ToLCV) disease and the cultural management practices viz., barriers and mulching, present investigation was carried out during the year 2000-2001 at B. A. College of Agriculture, Gujarat Agricultural University, Anand. The study on evaluation of various plant extracts against ToLCV indicated that pre-inoculation spray of phytoextract was more effective as compared to their application after ToLCV inoculation (Post-inoculation treatment). Among the plant species tested 10% aqueous leaf extract of Mirabilis jalapa and Catharanthus roseus as pre-inoculation spray were the best and recorded an inhibition of 93.33% while the same when applied after inoculation could exert an inhibition of 73.33% which was highest among its post-inoculation counterparts. The effect of pre- and post-inoculation treatment of chemicals and other substances didn't have much of a variation in case of growth regulators. The difference in ToLCV inhibition by pre- and post-inoculation treatment with gibberellic acid was not as large as seen in the case of phytoextracts. Although, gibberellic acid didn't inhibit or inactivate the leaf curl virus its pre- and post-inoculation spray resulted in least ToLCV infection (6.67 to 13.30%) followed by Guanidine hydrochloride (0.2%)) and Guanidine carbonate (0.2%). None of the different concentrations of cow urine could exert any inhibition of ToLCV. Moreover, the concentrations of cow urine that exceeded 20% caused phytotoxic effect at the true leaf stage of the tomato test plants. Whitefly count recorded at weekly interval from the yellow sticky traps installed in all the unsprayed plots of barriers indicated that the yellow sticky traps in grey cloth and nylon net barriers plots recorded least number of white flies as compared to those recorded in the rest of the traps throughout the season. Further, the numbers of white flies on the traps were as high as 29 in control where as grey and nylon net recorded only 15-18 whiteflies at 11 weeks after tomato transplanting. Among the different treatment combinations of barrier and insecticide spray, grey cloth barrier along with four sprays of triazophos @ 0.04% was at par with nylon net and superior to sunnhemp and rest of the treatment combinations. Grey cloth and nylon net emerged as significantly superior to rest of the treatments in preventing the immigrant whiteflies from entering the tomato plots thus reducing the ToLCV incidence (21.67% and 27.61% respectively) which in turn reflected in the tomato fruit yield (57.50 and 54.50 t/ha). The next best treatment was sunnhemp. From the two years of periodical observation and that of pooled it can be inferred that among the variety of mulches tested, the silver and grey mulches could maintain the ToLCV disease incidence below 10% even till 75 days after transplanting. Where as, at this period the incidence in control was 45.97% about four times of that recorded in the former cases (9.67 and 9.77% respectively). Pooled analysis of two years of mulch experiment data revealed that significantly least incidence was recorded at harvest jn silver and grey mulch plots due to corresponding least whitefly population. The next best treatment was "triazophos @ 0.04%. The black and silver mulch could also suppress the weed population significantly. Fruit yield was also highest in silver and grey (58.55 and 56.32 t/ha respectively) followed by triazophos. The ICBR computed for mulching as a management practice in tomato revealed that silver and grey gave maximum additional income (73,620 Rs/ha). The ICBR for silver and grey mulches were 1:2.77 and 1:2.60 respectively. Although triazophos @ 0.04% gave a very high ICBR of 1:19.73 but the ecofriendly nature of the management through mulching puts it at an advantage over the insecticide application. Hence, it can be concluded that, silver and grey mulching in tomato field can be practiced to keep the whitefly population at a low level thereby reducing ToLCV incidence.ThesisItem Open Access POWDERY MILDEW OF CORIANDER CAUSED BY Erysiphe polygon D.C. AND IT'S MANAGEMENT(AAU, Anand, 2002) DESAI, VIRAL K.; PATEL, J. G.Coriander (Coriandrum sativum L.) is an important spice crop. Coriander seeds and fresh coriander leaves are consumed as spice and for flavouring various culinary preparations, respectively. It is native of Mediterranean region. Today coriander is commercially grown in India, Morocco, Russia, Hungary, Poland, Czechoslovakia, Rumania, Guatemala, Mexico, USA, Bangladesh and Pakistan. Coriander belongs to family Apiaceae. In India, it was estimated that coriander is grown over an area of 3,22,000 hectares with a production of 3,08,000 hectares in the year 1997-98, while export of coriander seeds to foreign countries was to the tune of 26,826 metric tonne valued at around Rs. 58 crores for the year 1998-99. The crop can earn valuable foreign exchange. Powdery mildew is a major disease of coriander caused by Erysiphe polygoni D.C. The pathogen is air borne. It cause losses up to 15-40% in addition to considerable loss in quality of coriander seeds. Present investigations were carried out on patliogenicity, inlluence of sowing dates and weather parameters on development of disease, screening of germplasms/varieties, field evaluation of fungicides, phytoextracts and water spray against E. polygoni, at Vegetable Research Station, GAU, Anand. During the study in Rabi 2000-2001, it was observed that the powdery mildew of coriander appeared in late December - January - February and increased till harvesting. Infected plants showed typical symptoms of white ashy powdery coverage on foliar parts and stem. The fungus could not he multiplied under laboratory conditions. Therefore, in order to prove the pathogenicity, conidia obtained from the diseased plant parts were sprayed on plants of cultivar Gujarat Coriander-2. Among various sowing dates under study, the early sowing dates i.e. 20th October and 5th November were found superior to subsequent sowing dates i.e. 20th November, 5th December, 20th December and 5th January. Environmental factors played an important and vital role in development of disease. Periodical progression of disease intensity increased from 16.40 to 57.60 per cent. Positive and significant correlation was observed in case of wind speed and positive but non-significant correlation in case of maximum, minimum and mean temperatures. Disease was initiated in between late December to Early January. Among twenty-six different germplasms/varieties screened, no variety was found immune or resistant to powdery mildew infection. However, the germplasms CM-17, CM-26 and CM-25 recorded lower disease incidence i.e. 48.26, 50.93 and 51.20 per cent, respectively. Among different fungicides and phytoextracts tried in control of powdery mildew of coriander, Dinocap proved to be most effective fungicide followed by wettablc Sulphur with respect to disease intensity, seed yield and oil content. Phytoextracts were found next to fungicides in respect of disease control.ThesisItem Open Access STUDIES ON EVALUATION OF AGROCHEMICALS AND PHYTOEXTRACTS AGAINST Cercospora nicotianae, THE CAUSE OF FROG-EYE SPOT DISEASE OF BIDI TOBACCO(AAU, Anand, 2005) CHAUDHARI, SAHDEVBHAI L.; PATEL, B. N.Investigations on various media for establishing their suitability for favourable growth and efficacy of agrochemicals and bio-pesticides including phytoextracts for their inhibitory action against Cercospora nicotianae, the cause of frog eye spot disease of bidi tobacco under in vitro conditions were carried out at Bidi Tobacco Research Station, Anand Agricultural University, Anand during 2003-04. In subsequent study, effective fungicides, insecticides, readymade bio-pesticides and acqueous leaf extracts of plant species were tested against the disease under nursery conditions. Reaction of bidi tobacco varieties/genotypes against the disease under nursery conditions was also studied Out of 7 media evaluated, carrot leaf decoction agar, fennel leaf decoction agar, coriander leaf decoction agar and sava leaf decoction agar were found to be highly favourable for good growth of C nicotianae (52.40 to 60.80 mm colony diameter). Among these, fermel leaf decoction agar, coriander leaf decoction agar and sava leaf decoction agar were established for the first time as suitable media for the growth of the fungus (52.40 to 54.80 mm colony diameter) imder laboratory condition. Carbendazim, thiophanate methyl, benomyl, mancozeb and Cosco (Carboxin 37.5 % + Thirum 37.5 %) 75 WP were most effective and completely suppressed the growth of the fungus on carrot leaf decoction agar under in vitro condition. Out of 16 insecticides, carbaryl and dichlorovos were effective and inhibitated the growth to the extent of 85.9 and 82.6 %, respectively. Among 29 plant species evaluated, acqueous leaf extract of Tecoma stans @ 25 % was most effective (76.0 % inhibition); this was followed by E. citriodora (49.0 % inhibition). Six readymade bio-pesticides viz., Econeem, Biosoft, Halt, Vanguard, Monitor-WP and Biolep were found highly effective in inhibiting the growth of C. nicotianae in vitro; the per cent inhibition ranged between 75.3 and 92.4. Results of evaluation of effective fungicides, viz., carbendazim @ 0.025 %, thiophanate methyl @ 0.07 %, mancozeb @ 0.2 %, Cosco @ 0.3 % and benomyl @ 0.025 %, leaf extracts of plant species viz., Tecoma stans and Eucalyptus citriodora, both at 25 %, insecticides carbaryl @ 0.2 % and dichlorovos @ 0.05 % and readymade biopesticides viz., Econeem @ 0.075 % and Biosofl @ 0.4 % under nursery conditions revealed that among fimgicides, carbendazim and thiophanate methyl were most effective in the management of the disease giving better yield of transplants; these fungicides gave 100 and 96.6 % control, respectively. Between two plant species, acqueous leaf extract of T. stans gave 85.0 % control of the disease and significantly more number of transplants than control. Taking into account two most important attributes in the nursery viz., per cent disease intensity and transplants, two insecticides and two readymade bio-pesticides tested were not considered as effective against the disease. Among 10 different varieties/genotypes screened none was found free from the disease under nursery conditions. The variety GTH1, however, had minimum per cent disease intensity (45.60) and the variety Anand 119 had maximum per cent disease intensity (73.67). The results of the present investigations, thus, indicated that in addition to carrot leaf decoction agar, three more media viz., fennel leaf decoction agar, coriander leaf decoction agar and sava leaf decoction agar were established as favourable for the growth of C. nicotianae under laboratory condition. Two fungicides, carbendazim and thiophanate methyl, were most effective in the management of the disease in nursery. Efficacy of acqueous leaf extract of T. starts against frog-eye spot disease in nursery was established for the first time; it was found to yield significantly more number of transplants when compared with control. Leaf extract of T. stans could be used individually as botanical pesticide in minimizing losses due to the disease in question or it could be integrated with chemical flingicide/s. If integrated, it could help in minimizing frequency of applications of chemical fungicide/s, thus reducing the cost of seedlings production. Under these circumstances, it would also minimize the danger of resistance development in C nicotianae under nursery conditions. However, detailed integrated schedule would need to be worked out before it can be advocated to the growers. Since none of the ten varieties/genotypes of bidi tobacco was resistant, it ultimately suggested that more extensive work involving very large number of genotypes is needed in order to locate resistance or tolerance to frog-eye spot disease.ThesisItem Open Access STUDIES ON INTERACTION BETWEEN BRINJAL MOSAIC VIRUS AND ROOT-KNOT NEMATODE ON GROWTH OF BRINJAL {Solanum melongena L.)(AAU, Anand, 2003) CHOVATIYA, KUNALKUMAR P.; Patel, B. N.ThesisItem Open Access TRANSMISSION, HOST RANGE AND MANAGEMENT OF LEAF CURL VIRUS DISEASE OF CHILLI (ChLCV)(AAU, Anand, 2003) Patel, Amit Kumar P.; Valand, G. B.Chilli (Capsicum annuum L.) belongs to family Solanaceae is an important spice cum vegetable crop of India. Leaf curl is one of the formidable constraints seriously affecting production of the vegetable. Therefore, to investigate the transmission, host range and management practices viz., chemical and mulching, present investigation was carried out during the year 2001-2002 at B.A. College of Agriculture, Gujarat Agricultural University, Anand Campus. During survey the leaf curl disease in chilli was noticed in var>'ing proportions in different districts of middle Gujarat including Anand and Vadodara. The incidence of chilli leaf curl disease ranged from 56.0 to 74.0 per cent. High incidence of the disease was recorded from chilli growing area of Vadodara district (66.00%) followed by Anand (62.66%). Chilli leaf curl virus induced characteristics of vein clearing and thickening. There was extreme reduction in leaf size. Leaves showed leatheryness with marked puckering with an upward curling of leaf Transmission studies revealed that the minimum acquisition and inoculation feeding periods required by whitefly to transmit ChLCV were 1.30 and 2.00 hours, respectively. Each acquisition and inoculation feeding of 6 hours by vector resulted in to 60.0 and 70.0 per cent transmission of ChLCV respectively. The incubation period in plants varied 15 to 23 days. Fecundity study revealed that an average number of egg laying capacity of whitefly females on diseased plant (67.0 nos.) was high than healthy plant (60.1 nos.) Out of 20 plant species belonging to 8 families, 10 plant species were found susceptible to ChLCV. Among them Ageratum conyzoids was found highly susceptible. While Carica papaya and Euphorbia geniculata were less susceptible to leaf curl. Eighteen genotypes of chilli were screened for ChLCV reaction under field condition. Genotypes ACS-99-5, ACS-2000-Ol and G-4 were found moderately resistant (23.0 to 30.0%) to ChLCV. Other remaining genotypes were susceptible, moderately susceptible or highly susceptible, among them genotype S-49 was noticed as highly susceptible (75.5%). The study on evaluation of various chemicals against ChLCV indicated that four spray of triazophos @ 0.04 per cent emerged as significantly superior to the rest of the treatment in preventing the mean whiteflies (0.345) population thus, reduced ChLCV (20.0%) incidence. The next best treatment was triazophos @ 0.04 per cent + methyl-o-demeton @ 0.03 per cent with an incidence of (25.0%) at harvest, followed by methyl-o-demeton @ 0.03 per cent with an incidence of (30.06%) at harvest. Thus, it could be concluded that chilli crop with four sprays of triazophos @ 0.04 per cent starting from 15 DAT reduced the ChLCV disease incidence and whitefly population. Amongst the various mulches silver colour performed significantly superior to the rest of the treatments by preventing the entry of whitefly (0.203 per leaf) into main crop and thereby reducing ChLCV disease incidence (11.81%) at harvest. The next best treatment was grey colour mulch with an incidence (12.49%) and at par with silver colour mulch, followed by triazophos @ 0.04 per cent with an incidence of (19.13%). Cow urine was not effective in reducing whitefly population and leaf curl disease incidence. Mulch treatment additionally suppressed the weed population significantly in chilli field. Thus, it can be concluded that silver and grey mulching in chilli field can be practiced to keep the whitefly population at a lower level and there by reduced leaf curl disease incidence.ThesisItem Open Access STUDIES ON A MOSAIC DISEASE OF BRINJAL [Solanum melongena L.](AAU, Anand, 2002) JHA, SOMESH; PATEL, B. N.A mosaic disease characterized by mosaic pattern,puckering, slight distortion and reduction of leaves with blistered appearance of leaf surface and general stunting of infected brinjal (Solanum melongena L.) plants was observed in the fields of Anand and its vicinity in middle Gujarat over the past several years.Therefore, the present investigation was undertaken to study symptomatology, extent of spread, mode of transmission, biophysical properties, a limited host range and serology of the causal virus with a view to ultimately establish its identity. Plants of brinjal cv. Doli-5, when inoculated artificially with the Virus by common leaf rub method, produced typical mosaic symptoms within 3 to 4 weeks. These symptoms were identical to those Observed under field conditions.Field survey revealed that disease incidence ranged from 6 to 65%, the average incidence being 26% in Anand and surrounding villages. The virus was found to be transmissible by mechanical means only. It was neither seed-borne nor it could be transmitted by Aphis craccivora(Koch) or A. gossypii (Glover) in repeated series. The thermal inactivation point of the virus in crude sap was determined between 65 and 70°C and dilution end point at 10 to power 3.it remained infective in crude sap upto 8 hours at room temperature (25-30°C) and 120 hours (5 days) at 5°C temperature on brinjal cv. Doli-5. Host range of the virus was restricted to the members of the family Solanaceae only. Three tobacco species viz., Nicotiana tabacum (cv. Anand 119), N.trigonophylla and N. glauca were observed to produce typical mosaic symptoms. Other four plant species viz., Datura stramonium , Lycopersicon esculentum, Capsicum annum and Solanum tuberosum were proved to be symptomless hosts of the virus. Serological test by DAC-ELISA (Direct Antigen Coating- Enzyme Linked Immunosorbent Assay) confirmed the serological relationship of this virus to the family Potyviridae. On the basis of symptomatology, transmission behaviour, biophysical properties in crude sap, host range and serology, the virus causing mosaic disease of brinjal was established as a member belonging to the family PotyviridaeThesisItem Open Access ALTERNARIA BLIGHT OF MUSTARD AND ITS MANAGEMENT(AAU, Anand, 2004) CHAUDHARY, MADHAV RAMJIBHAI; Patel, S. T.Indian mustard [Brassica juncea (Linn.) Czem and Coss], an important oilseed crop, ranks second next to groundnut in India. It yields valuable edible oil and is rich from nutritional point of view. Altemaria blight, caused by four species of Alternaria viz., A. hrassicae, A. hrassicicola, A. raphani and A. alternata, is an important disease . of cruciferous crops in India. Investigations were carried out to study effective technique for detection of pathogen from seeds, location of pathogen in seed, varietal response in respect of seed-borne nature of the pathogen as well as in vitro and in vivo evaluation of phytoextracts, fungicides and bioagent(s) against this disease. The pathogenic isolate of Alternaria alternata showed faster growth, produced greenish black to almost black colonies containing ovoid to oblong septate conidia measuring 21 to 56 X 10.5 to 17.5 µm. Among the three different methods employed for detection of A. alternata from seeds of mustard (cv. Varuna), SBM proved to be more effective than APM and deep freeze method. The component plating technique revealed the pathogen's (A. alternata) presence only in the seed coat. Embryos and cotyledons were found free from infection. None among the ten cultivar/genotype studied was found completely free from seed infection by Alternaria alternata. SKM-0201 recorded highest (11 .50 %) seed infection, whereas least (5.75 %) was observed in cultivar GM-1. Of the seven fungicides evaluated against A. altemata in in vitro, hexaconazole showed complete inhibition of mycelial growth. Copper oxychloride @ 0.15 per cent, mancozeb @ 0.20 per cent and thiram @ 0.20 per cent showed 91.44, 82.23 and 77.27 per cent inhibition, respectively. Among the two plant extracts, neem leaf extract @ 15 per cent showed 60.52 per cent inhibition and proved better than tulsi. Both Trichoderma viride and T. harzianum proved effective and showed 80.92 and 73.02 per cent inhibition of mycelial growth. Field evaluation of seven fungicides, two phytoextracts and one bioagent against Altemaria blight disease revealed mancozeb @ 0.2 per cent as most effective with least disease intensity (9.13 %) and increased the yield by 11.44 per cent over control. Yield differences were non significant. Iprodione + carbendazim and chlorothalonil were found next best fungicides. Bioagent, phytoextracts and only seed treatment with thiram revealed non significant differences with control for disease intensity.ThesisItem Open Access LEAF BLIGHT OF ONION CAUSED BY Alternaria alternate (Fr.) KEISSLER AND ITS MANAGEMENT BY DIFFERENT FUNGICIDES(AAU, Anand, 2005) KUMARI, HEMLATA; PATEL, S. J.Onion (Allium cepa L.) is an important cash crop used as vegetable, condiment and medicine. Onion is cultivated throughout the world under an area of 22.81 lakhs hectares with total production of 380.22 lakhs MT. Several factors have been identified which limit the onion production and productivity. Among these, leaf blight caused by Alternaria spp. is an important disease affecting both bulb and seed crop of onion found in India. The disease first appeared in the field as whitish circular to irregular specks, which were less than 1 mm in diameter. These specks developed into a whitish sunken lesion, when the conditions were congenial for the disease development. The typical symptom of this disease is dark purple/ brownish patches with yellow halo and more prevalent on lower leaves. Pathogen was isolated from infected leaves of onion showing typical symptoms of purple or dark brown spots having concentric rings on PDA and Koch's postulates were established for pathogenisity test. The pure culture of isolated pathogen was sent for identification to Indian Type Culture Collection (I.T.C.C), I.A.R.I., New Delhi-110 012 and idenfified as Alternaria alternata (Fr.) Keissler. The study revealed that the fungus produced mycelial growth on PDA which was septate and whitish green in colour when young, later turned light green to dark brown within 10 days and branched irregularly at acute angle. The conidiophores of the fungus were light brown, simple and septate. Conidia were light to dark brown. muriform with 1-5 transverse septa and 0-2 longitudinal septa, variable in size and shape. They were obclavate to oval in shape with rudimentary beak and measured 10.83-59.57 X 5.42-16.25 µm (av. 31.73 x 11.54 µm). Maximum growth of Alternaria alternata was seen on media Potato Dextrose Agar at pH 6.0. Among the nine fungicides tested in vitro, mancozeb (Dithane M-45, 5000 ppm), carboxin + thirum (Cosko, 1500, 3000 and 6000 ppm) and copper oxichloride (Blitox, 5000 ppm) were found significantly superior over the rest of the fungicides as judged by complete inhibition of growth of Alternaria alternata (Fr.) Keissler. Propiconazole (Tilt) was showing reverse effect on the growth of test fungus. As the concentration was increasing, per cent inhibition was decreasing. Total nine fungicides used in field against leaf blight disease of onion were found significantly effective in reducing the disease incidence. Three spray of mancozeb (Dithane M-45, 0.25 %) at 20 days interval was the most effective fungicide followed by metalaxyl + mancozeb (Ridomil MZ, 0.3 %), iprobenfos (Kitazin, 0.1%) and chlorothalonil (Kavach, 0.2%) in managing the leaf blight disease of onion. With regard to yield, significantly highest bulb yield was recorded in the treatment of mancozeb (Dithane M-45, 0.25 %). Tip burning effect on onion leaves was seen by spray of carboxin + thirum (Cosko, 0.3 %). Among the nine insecticides tested in vitro, monocrotophos (Nuvacron, 500 and 1000 ppm) and cypermethrin (CipIon-25, 200 ppm) were found significantly superior over the rest of the insecticides judged by maximum per cent inhibition of growth of A. alternata. Endosulfan acted as nutritive for fungal growth. As the concentration was increasing, fungal radial growth was also increasing. Chemical analysis of healthy and diseased plant / plant parts revealed that the concentration of phenol increased in diseased leaf parts by 1024.25 µg/g than healthy ones and 1060.6125 µg/g in diseased bulb parts than healthy ones. Similarly, the concentration of protein decreased in diseased leaf parts by 0.6123 g/lOOg than healthy ones and 0.4400 g/100g in diseased bulb parts than healthy ones.ThesisItem Open Access RHIZOSPHERE MYCOFLORAS OF SOYBEAN, THEIR BIOLOGICAL INTERACTIONS WITH FUSARIUM AND SIGNIFICANCE(AAU, Anand, 2003) Manubhai, Maisuria Kuldeepkumar; PATEL, S. T.Soybean [Glycine niax (L.) Merr.] is an important pulse crop. Rhizosphere is characterized by greater microbial activity than the soil away from plant roots. Therefore, quantitative and qualitative assessment of rhizosphere mycofloras from healthy and diseased soybean plants, their pathogenicity and identification, biological interaction among mycofloras, biochemical analysis, of root exudates, influence of root exudates on spore germination of rhizosphere fungi and effect of rhizosphere fungi on germination, root length, shoot length and vigour index of soybean were carried out during 2001-2003 at Department of Plant Pathology, B.A.C.A., Anand. Maximum number of fungi were associated in the rhizosphere of diseased soybean plants than healthy ones. Trichoderma viride was found only from healthy soybean plants, whereas Fusarium solani, Macrophomina phaseolina, Pythhim aphanidennatum and Rhizoctonia sp. were associated with diseased plants. The population of fungi were significantly higher in rhizosphere soil of 30 days old soybean plants in both healthy and diseased soybean plants. Fusarium oxysporum. Fusarium solani, Macrophomina phaseolina, Pylhium aphcinidermalum and Rhizoctonia sp. obtained from rhizosphere of diseased soybean plants were pathogenic. l\\c study on biological interactions among mycofloras including two pathogenic and one non-pathogenic Fusarium revealed considerable range of inhibition between certain interacting rhizosphere fungi. The inhibition zones developed between pathogenic Fusarium oxysporum and other rhizosphere fungi and aJso between pathogenic Fusarium solani and other rhizosphere fungi are of quite significance because these fungi can influence adversely the biological growth of each other in the rhizosphere. Trichoderma viride showed more or less antagonism towards all the rhizosphere fungi and arrested the growth of fungi. The roots of healthy soybean plants secreted significantly more amount of phenol and amino acid than diseased plants, whereas more amount of soluble sugar was detected in root exudates of diseased soybean plants than healthy ones. The spore germination of rhizosphere fungi occurred significantly maximum in root exudates of diseased soybean plants than the exudates of healthy plants. The pots inoculated with Pythium aphanidermatum decreased seed germination, root length, shoot length and vigour index of soybean maximum than the other fungi which also showed adversely effects on these parameters. Trichoderma viride enhanced the seed germination, root length, shoot length and vigour index.