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Govind Ballabh Pant University of Agriculture and Technology, Pantnagar

After independence, development of the rural sector was considered the primary concern of the Government of India. In 1949, with the appointment of the Radhakrishnan University Education Commission, imparting of agricultural education through the setting up of rural universities became the focal point. Later, in 1954 an Indo-American team led by Dr. K.R. Damle, the Vice-President of ICAR, was constituted that arrived at the idea of establishing a Rural University on the land-grant pattern of USA. As a consequence a contract between the Government of India, the Technical Cooperation Mission and some land-grant universities of USA, was signed to promote agricultural education in the country. The US universities included the universities of Tennessee, the Ohio State University, the Kansas State University, The University of Illinois, the Pennsylvania State University and the University of Missouri. The task of assisting Uttar Pradesh in establishing an agricultural university was assigned to the University of Illinois which signed a contract in 1959 to establish an agricultural University in the State. Dean, H.W. Hannah, of the University of Illinois prepared a blueprint for a Rural University to be set up at the Tarai State Farm in the district Nainital, UP. In the initial stage the University of Illinois also offered the services of its scientists and teachers. Thus, in 1960, the first agricultural university of India, UP Agricultural University, came into being by an Act of legislation, UP Act XI-V of 1958. The Act was later amended under UP Universities Re-enactment and Amendment Act 1972 and the University was rechristened as Govind Ballabh Pant University of Agriculture and Technology keeping in view the contributions of Pt. Govind Ballabh Pant, the then Chief Minister of UP. The University was dedicated to the Nation by the first Prime Minister of India Pt Jawaharlal Nehru on 17 November 1960. The G.B. Pant University is a symbol of successful partnership between India and the United States. The establishment of this university brought about a revolution in agricultural education, research and extension. It paved the way for setting up of 31 other agricultural universities in the country.

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  • ThesisItemOpen Access
    Cultural studies and evaluation of fungicides, botanicals, essential oils and biocontrol agents against Bipolaris zeicola (Stout) Shoemaker., the causal organism of northern leaf spot of maize
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Rana, Haripal; Pradeep Kumar
    Northern leaf spot of maize caused by Bipolaris zeicola (Stout) Shoemaker is one of the important diseases of maize. The disease is present in almost all maize growing areas and is a major limiting factor for maize cultivation. Therefore, in vitro and glasshouse studies were conducted to elucidate different aspects of pathogen biology and effective management of disease. Pathogen produced golden yellow to dark olive-brown conidial colonies and conidia were curved, long elliptical to spindle shaped, with rounded ends having 2 to 12 septa. Pathogen produced whitish grey colony on PDA when young, becoming blackish grey when mature with entire or irregular margin, hyphae hyaline to dark brown, septate and branched. The results of media on different temperature revealed that maximum mycelial growth (90.00 mm) was found in Oat meal agar at 30⁰C followed by 65.00 mm on Potato dextrose agar at 30⁰C. On media in different wavelength recorded maximum radial growth on Richard’s synthetic agar in yellow light (59.00 mm) and minimum growth (22.67 mm) was found in Oat meal agar media by yellow light. pH 5 was found suitable for the maximum growth (41.67 mm) and pH 9 for minimum growth (23.33 mm) of the fungus. Among different carbon sources, maximum growth (60.33 mm) observed in lactose amended media and minimum growth (50.33 mm) in manitol amended media. In different nitrogen sources, maximum growth (59.33 mm) was observed in sodium nitrate amended media and minimum growth (24.00 mm) in ammonium nitrate amended media. Among different non systemic and combi fungicides Hexaconazole (5%) + Captan (70%) 75% WP performed well at all the concentrations then other fungicides. Among different systemic fungicides, Propiconazole (25% EC) revealed good results at all concentrations, followed by Tebuconazole (25.9% EC). Best essential oils and botanicals for maximum growth inhibition of test pathogen were peppermint oil (87.41%) and marigold extract (58.52%), respectively. Among the biocontrol agents evaluated by dual culture and volatile method, maximum inhibition of mycelial growth were found in Th-14 (77.70%), and Th-39 (54.82%), respectively and minimum inhibition of mycelial growth were recorded in Th-17 (41.39%) and Th-19 (31.32%), respectively. Among different inoculation methods tested the maximium disease severity was found in silking stage in variety Pragati (13.67%) by stem injection method in glasshouse experiment. Among different treatments fungicides @ 50 ppm, essential oils @ 25 ppm, botanicals @ 5% and biocontrol agents @ 5% evaluated in pots, fungicidal sprays was found best among all the treatments and gave maximum disease control over check.
  • ThesisItemOpen Access
    Management of root knot nematode (Meloidogyne enterolobii) in tomato and guava using bio-intensive approaches
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Shubham Kumar; Sharma, Roopali
    Meloidogyne enterolobii is a tropical or subtropical nematode and has a broad host range, including cultivated plants and weeds. For decades, the control of sedentary nematodes has relied heavily on chemical nematicides. In order to avoid excess use of nematicides, other alternates for ecofriendly management techniques like Biological control and Biofumigation can be explored. The present investigations were carried out to study bio-intensive management of Meloidogyne enterolobii causing root-knot in tomato and guava. The Identification of root knot nematode (Meloidogyne enterolobii) was done microscopically. The females of M. enterolobii showed characteristic pear-shape and pearly-white colour. The perineal pattern of adult females showed an oval shape dorsal arch which is usually high and round and weak lateral lines sometimes present with large phasmids. In vitro effect of Biocontrol Agents namely, Trichoderma asperellum (Th-14) and Pseudomonas fluorescens (Psf-173) and Biofumigants namely, Brassica juncea (mustard) variety Kranti and Raphanus sativus (raddish) variety Japanese white, was studied on the hatchability of eggs and mobility of second stage juvenile (J2) of M. enterolobii. Results revealed that, the rate of egg hatching and mobility of J2 decreases with the exposure of Biocontrol Agents and Biofumigants in different concentrations. Among all treatments, maximum reduction in egg hatching was recorded in Brassica juncea (67.00%) followed by Raphanus sativus (63.73%), Trichoderma asperellum (56.04 %) and Pseudomonas fluorescens (46.15%) after 96 hours of incubation period at 15 percent concentration over control (91.00% hatching of eggs). While, in case of juvenile mortality, Brassica juncea showed that maximum mortality of juveniles (92.60%) followed by Raphanus sativus (87.36%), Trichoderma asperellum (60.00%), Pseudomonas fluorescens (55.78%) over control (5% mortality of juveniles) at 15 concentration and incubation period of 96 hours. Scanning Electron Microscopy (SEM) was performed to study the mode of action of Trichoderma on the eggs of Meloidogyne enterolobii. Mycelial parasitization of eggs through Trichoderma showed complete coiling which finally resulted in the desiccation and killing of eggs. The management of root knot nematode (M. enterolobii) using biointensive approaches was studied under the glass house conditions in tomato and guava. The experiments were laid out using different treatments of Biocontrol agents (Trichoderma asperellum (Th-14), Pseudomonas flourescens (Psf-173), PBAT 3 (consortium of Th14 & Psf173) and Paecilomyces lilacinus (commercial) with the combination of Biofumigation (Brassica juncea & Raphanus sativus). Nematicide carbofuran was used as chemical check. All the treatments showed positive effect on the growth parameters of tomato and guava plants. In tomato, combination of BAT3+Biofumigation(M) resulted in maximum fresh root (7.38g) and shoot weight (36.07g) with minimum number of root galls (18.33galls per root system) as compared to the combination of other treatments. Whereas, in guava, maximum fresh root weight was found in the case of both treatments CF+Biofumigation(R) (2.57g) and Psf173+Biofumigation(R) (2.57g) which was statistically similar to PBAT3+Biofumigation(R) (2.51g). Minimum number of root galls (17.67galls per root system) was observed in PBAT3+Biofumigation(M).
  • ThesisItemOpen Access
    Studies on Colletotrichum capsici (Syd.) Butler and Bisby causing anthracnose of chilli and its ecofriendly management
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-07) Prajapati, Manoj Kumar; Rawat, Shilpi
    Chilli (Capsicum annum L.) is one of the most important commercial crops of India. The sustainability of chilli production is threatened by various fungal, bacterial and viral diseases. Out of more than fourteen fungal diseases affecting chilli, anthracnose caused by Colletotrichum capsici is one of the oldest and most destructive disease which is reported worldwide. Focusing on the eco-friendliness and sustainability of the management methods, the present investigation was undertaken to study the cultural and morphological characteristics, identification of resistant sources through screening and management of the disease through botanicals fungicides. The in vitro evaluation of different inoculation methods revealed that pin prick method was the most effective for inciting chilli anthracnose. Pin prick method produced maximum lesion length and had recorded the highest disease severity when compared to the other three viz., fruit dip, spray and spot inoculation methods. The OMA and CFDA were found to be the best medium for the growth and sporulation of the fungus, respectively. The fungus produced greyish to white colony with fluffy texture and smooth margin on OMA, PDA, CDA, RSA and MEA whereas dark brown to black colony with thin and scanty texture was observed in CFDA. The maximum radial growth of the fungus in PDA was obtained at 30 0C temperature and pH 7.0. The studies on morphological characteristics of pathogen under stereo-binocular and electron microscope showed that mycelium was dense, septate and brown in colour. It produced acervuli having septate setae, sickle shaped brown coloured conidia with oil globule in the center. In vitro evaluation of botanicals revealed that neem @ 15% had the highest growth inhibition (44.21%) followed by tulsi @ 15% and neem @ 10%. Under field conditions, neem @ 15% had the lowest PDI and highest yield followed by marigold @ 15%. The in vitro screening of chilli varieties against C. capsici revealed that out of ten varieties six were found to be moderately resistant whereas two each exhibited susceptible and highly susceptible disease reaction. Hence, it can be concluded that eco-friendly management of anthracnose disease can be achieved by
  • ThesisItemOpen Access
    Study on feasibility of spawn production through basidiospores of Pleurotus sajor-caju (Fr.) Singer
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-07) Purohit, Rahul; Mishra, S.K.
    Among the all cultivated mushrooms, Pleurotus is the second most important mushroom in the world. At present, many species of Pleurotus mushroom have developed. Out of them Pleurotus sajor-caju is the most popular species. This mushroom can be easily grown in various agricultural organic substrates within the short time duration. It can tolerate the wide range of temperature from 10-30oC. Short duration crop, easy cultivation, fast growing habit, durable post-harvest life and easy for value addition are some of its other special characters and due to these characters it becomes very popular among the mushroom growers and consumers. Its cultivation is based on the quality of 1st generation inoculum (master inoculum), which is prepared by the method of tissue culture on the wheat grains. This method usually takes 15-20 days to prepare 1st generation inoculum. Due to this prolonged incubation period it is affected by fungal and bacterial contamination. In the beginning of the research, basidiospores were collected on black circular paper which was defined as Spore Printed Circular Paper (SPCP). To evaluate the number of spores in a circular paper disc, it was inoculated into sterilized distilled water and was further diluted to the strength of 10-2. The average numbers of spores/ml at 10-2 dilution strength was found to be approx. 15.4 × 104. The SPCP was further evaluated on the solid potato dextrose (SPD) and liquid potato dextrose (LPD) medium to observe the fungal and bacterial contamination. It was found that, sterilized distilled water treated SPCP (SDWT-SPCP) did not propagate any fungal and bacterial contamination in SPD and LPD medium and also resulted 88 mm radial growth on 20 DAI and 0.92 g dry mycelial weight on 30 DAI, respectively. However, their respective checks (tissue culture) performed 89 mm radial growth on 10 DAI and 0.99 g dry mycelial weight on 30 days. In another method (Spore Printed Water) the basidiospores of P. sajor-caju were collected in sterilized distilled water and it was found that Spore Printed Water propagate bacterial contamination after inoculation of SPD medium. So, this method was rejected for proceeding study. The cultural studies were also done using SDWT-SPCP with different media (potato dextrose agar, Pleurotus liquid media (modified), oat meal agar, corn meal agar and malt extract agar), pH (5, 6, 7 and 8) and temperature (15, 20, 25 and 30oC) and it was observed that malt extract agar media having pH 7 at a temperature of 25oC was found optimum for the growth of spore culture. As per the in-vitro results, the broth based spore culture and spore suspension prepared by using 3 SPCP/200 ml LPD and 1 SPCP/100 ml sterilized distilled water, respectively were found to be best out of 5 treatments of the 1st generation inoculum. The 1st generation broth based spore culture was ready to use within 4 days after the inoculation and spore suspension was used immediately without prior incubation in contrast to 10 and 11 days of incubation period taken in the check (tissue culture) and grain based master spawn, respectively. Consecutively, 2nd generation inoculum was prepared from the 1st generation inoculum of broth based spore culture and spore suspension. The 2nd generation inoculum prepared from broth based spore culture and spore suspension were taken 13 and 14 days, respectively without any contamination while, three other treatments; chloramphenicol treated-SPCP, sterilized distilled water treated-SPCP and dry-SPCP had taken 16 days to prepare the 2nd generation inoculum in which 40%, 10% and 40% contamination was found, respectively. Out of all the above treatments of 2nd generation inoculum, maximum 246.8 g yield and minimum 127.6 g yield/kg of wet wheat straw was found in broth based spore culture and spore suspension with 72.59% and 37.47% biological efficiency, respectively.
  • ThesisItemOpen Access
    Sclerotial viability of Rhizoctonia solani Kühn in relation to incidence of web blight in moongbean and its management
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-07) Shweta; Yadav, L.B.
    Moongbean (Vigna radiata L. Wilczek) is third most important pulse crop among the thirteen food legumes grown in India which is grown in almost all the states due to its triple use as food, fodder and fertility. Moongbean crop is infected by number of diseases among them web blight caused by Rhizoctonia solani Kühn cause heavy losses and reduce the productivity of the crop specially in tarai region of Uttarakhand where humid and warm environmental conditions prevails. The salient findings of the present investigation are summarized as follows: Phytotoxic effect of culture filtrate of R. solani showed up to79.58% reduction in seedling length of moongbean. Different fungicides and botanicals were evaluated as seed treatments for their effect on seedling vigour and viability of sclerotia admixtured with moongbean seeds. Among fungicides vitavax power (carboxin 37.5% + thiram 37.5% WS), azoxystrobin and adexar (fluxapyroxad 62.5 g/l + epoxiconazole 62.5 g/l) were found most effective in inhibiting mycelial growth from sclerotia. Vitavax power (carboxin 37.5% + thiram 37.5% WS) also showed highest germination per cent and vigour index. Among plant extracts thuja gave best results in suppression of mycelial growth from sclerotia and under glass house conditions showed highest germination per cent and vigour index. Neem was found most effective under in vitro condition and resulted highest germination per cent and vigour index. Adexar (fluxapyroxad 62.5 g/l + epoxiconazole 62.5 g/l) and tebuconazole were found most effective in inhibiting radial growth of the fungus even at lower concentration. Nativo (tebuconazole 50% + trifloxystrobin 25% WG) and azoxystrobin were next in order. Adexar (fluxapyroxad 62.5 g/l + epoxiconazole 62.5 g/l) was also found effective in inhibiting viability of sclerotia. All three fungal antagonists i.e., T. harzianum 14, T. harzianum 39 and TsM1 were found effective against R. solani. T. harzianum 39 being the best. Under field condition seed treatment with carbendazim + thiram @ 3 g/kg seed and two foliar sprays of nativo (tebuconazole 50% + trifloxystrobin 25% WG) @ 700 g/500 l/ha at 10 days interval showed highest decline in disease severity and highest grain yield followed by seed treatment of PBA-3 @ 6 g/kg seed and two foliar sprays of nativo (tebuconazole 50% + trifloxystrobin 25% WG) @ 700 g/500 l/ha.
  • ThesisItemOpen Access
    Seed-borne nature and management of Alternaria alternata (Fr.) Keissl., the cause of fruit rot in chilli (Capsicum annum L.)
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-07) Nagarjuna, S.N.; Tewari, Rashmi
    Chilli (Capsicum annuum L.) is one of the most important commercial crops and highly valued for its flavour, colour as well as its antioxidant compounds. It is affected by many diseases such as damping off, powdery mildew, anthracnose, leaf spot and fruit rot. Fruit rot of chilli has been found to be quite serious and wide spread disease which causes significant losses in fruit production and seed quality. Investigations were undertaken to study the fruit rot, its pathogen and effect of seed-borne infection on seed quality parameters, detection, transmission, location of seed-borne inoculum in various seed components, persistence of pathogen on/in the seed and in vitro evaluation of fungicides against the pathogen. The symptoms of disease appeared on all aerial plant parts. At the fruit setting stage severe fruit rot was observed. The fungus has also been found on seeds collected from infected fruits. The seeds from infected fruits were discoloured and covered with mycelial growth of the fungus. On the basis of cultural and morphological characteristics, the fungus was identified as Alternaria alternata by ITCC, New Delhi. Spores of the fungus appeared in long chains on the surface of the seeds when observed under stereo binocular. The maximum radial growth of the fungus was observed on Potato Dextrose Agar medium, at 25±1°C after 7 days of incubation. The fungus associated with the infected seeds reduced seed germination, adversely affected the seedling growth, seed weight & seed viability. The seedlings raised from infected seeds increased abnormal seedlings and exhibited seedling infection. Seed when stored at ambient storage conditions, the longevity of the fungus in seed went on reducing with the increase in storage period. Standard blotter method was found to be the best as it exhibited maximum recovery of fungus from infected seeds as compared with other methods. The presence of fungal mycelium was observed in the seed coat, pericarp and endosperm. Seed components were invaded with the fungus leading to disintegration of the seed tissues. Seed treatment with fungicides (Thiram 75% DS; Mancozeb 63% +Carbendazim 12% WS; and Metiram 55% + Pyraclostrobin 5 % at 500 μgml-1) enhanced the seed germination, reduced abnormal seedlings and seedling infection. The fungicides when evaluated against A. alternata in vitro at different concentrations (25 μgml-1, 50 μgml-1, 75 μgml-1, 100 μgml-1) showed that all the fungicides used in the present investigation significantly inhibited the radial growth of the fungus, irrespective their concentration, as compared to check. However, Tebuconazole 25.9% EC; Trifloxystrobin 25% + Tebuconazole 50% WG; Thiram 75% DS at 50ppm, 75ppm , 100ppm and Azoxystrobin 11% + Tebuconazole 18.30% SC at 100 ppm and Captan 70%+ Hexaconazole 5% WP at 50ppm & 100ppm exhibited maximum growth inhibition of the fungus.
  • ThesisItemOpen Access
    Status and distribution of potato cyst nematode (Globodera spp.) and other major plant parasitic nematodes associated with potato (Solanum tuberosum l.) in Kumaon region of Uttarakhand
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-07) Deepak Prakash; Satya Kumar
    Potato is the most important vegetable tuber crop in Uttarakhand. It is produced all around the year and plays a significant role in the economy of Uttarakhand. Plant parasitic nematodes are one of the limiting factors in potato production which result in quality deterioration and yield loss. The estimated yield-loss caused by plant parasitic nematodes in potato around the world is 12.2 per cent. Keeping this view, an extensive survey was conducted in four districts of Kumaon region of Uttarakhand to study the status of important plant parasitic nematodes associated with potato. Soil samples were collected from different villages of the districts and analysis was done in Nematology Laboratory of Department of Plant Pathology. Analysis revealed the presence of ten genera of plant parasitic nematodes associated with potato likely; Globodera spp., Meloidogyne spp., Pratylenchus spp., Ditylenchus spp., Trichodorus spp., Helicotylenchus spp., Tylenchorhynchus spp., Criconemoides spp., Aphelenchus spp. and Tylenchus spp. Among these Aphelenchus spp. was predominant in Nainital district with incidence of (85.29%) whereas occurrence of potato cyst nematode was recorded in (54.28%) villages of which Edidhar village showed maximum population of cysts i.e. (45 cysts/200 cc soil). However, four genera of nematodes showed their 100 per cent frequency of occurrence in Almora viz. Helicotylenchus spp. Tylenchorhynchus spp., Aphelenchus spp. and Tylenchus spp. while at Durganagar and Natadol, occurrence of potato cyst nematode was also observed with population density of 32 cysts/200 cc soil)and 23 cysts/200 cc soil respectively. In Pithoragarh, Tylenchorhynchus spp. was recorded maximum whereas two government potato farm i.e. (Tiksen and Balati) were also found to be heavily infested with potato cyst nematode supporting (250 cysts/200 cc soil) and (158 cysts/200 cc soil) respectively. In Champawat, Devidhura village showed maximum nematode population and also found to be heavily infested with potato cyst nematode (54 cysts/200 cc soil). In present study, altitude showed positive correlation with the population of Globodera spp. However, soil pH was found to be negatively correlated with the population buildup of Pratylenchus spp., Meloidogyne spp., Tylenchorhynchus spp. and Helicotylenchus spp. Soil moisture showed its positive correlation with Meloidogyne spp., Pratylenchus spp., Ditylenchus spp. and Helicotylenchus spp while population buildup of Globodera spp., Meloidogyne spp., Pratylenchus spp., Helicotylenchus spp., Trichodorus spp. and Tylenchorhynchus spp. was found to be negatively correlated with soil temperature On the basis of survey, it can be inferred that occurrence of potato cyst nematode is a serious threat to potato cultivation and it may emerge as the serious endemic pest in Uttarakhand. Instant attention of the administrators and researchers is required to take appropriate decision for planning strong domestic quarantine regulation to limit their further spread. Surveillance of nematode populations in the potato growing areas of the state is also required at regular time interval so, as to keep a strict watch to attain their economic threshold level through which timely preventive management strategies could be taken.
  • ThesisItemOpen Access
    Characterization of Ophiocordyceps sinensis - the caterpillar fungus
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-07) Kunwar, Deepshikha; Sharma, Geeta
    Ophiocordyceps sinensis (syn. Cordyceps sinensis) commonly known as caterpillar fungus which parasitizes the larvae Himalayan bat moth (Hepialis armoricanus). There are about 400 species of Ophiocordyceps. Some reported species of Ophiocordyceps are O. gansuensis, O. crassispora, O. kangdingensis, O. nepalensis, O. multiaxialis, O. militaris and O. sinensis. O. sinensis is an entomophagous fungus which belongs to Division Ascomycota. It is found at an altitude of 3000 to 5000m, mostly at 3500 to 4500m in the cold and arid region. O. sinensis is reported as a reputed medicinal fungus which is used against the treatment of many diseases and disorders. In present study fruit body of caterpillar was collected from Bona village, Panchachuli Hills of Munsyari of District Pithoragarh, Uttarakhand. Fungus isolated from fruit body on two media namely SDAY and PDA media. After isolation of fungus on media, anamorphic stage was observed under Scanning Electron Microscope in which conidia were appears in chain and having spine like outgrowth on the surface. DNA was isolated from fungus mycelium and DNA was amplified with the help of PCR by using primers 5.8SR, ITS4, ITS1, NS7 and NS8. Among these primers, 5.8SR and ITS4 primers forms band in between 500 and 600 bp. Four different media were used to check the growth of the fungus from which maximum mycelium was harvested from SDAY media. Best temperature and pH for the growth of the fungus reported was 18º±2ºC and 6.0, respectively. O. sinensis mycelium can also harvested from cereal grains substrate if required in bulk amount and the best substrate observed was wheat cereal grains. Fungus mycelium was also inoculated on 3rd stage larvae of two insects Pod Borer and Bihar hairy caterpillar of Soybean crop but fungus was unable to induce infection. Demand of this mushroom is very high and market is growing very fast for this fungus worldwide. Due to its high demand and more consumption, mushroom from natural habitat is being harvested resulting in extinction of the mushroom, as a result of which it becomes very difficult to harvest wild O. sinensis. Now a day’s alternatives for its production are being searched and a good alternative for its production which came out is artificial production of mycelium of the fungus. For such studies present experiments were conducted and observed that fungus can be cultured under lab conditions also which could help in conservation of natural fruit body can artificially produced mycelium can be utilized for further medicine production.
  • ThesisItemOpen Access
    Seed discoloration in rice: Causes and their effect on seed quality
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-07) Jitesh Kumar; Bijendra Kumar
    Rice not only constitutes the most important staple food for half of the world’s population, especially in Asia but is also an important export commodity. In India, rice crop is attacked by several bacterial, fungal, viral pathogens and pests. However, “grain discoloration” is a complex disease due to infection by certain microorganisms on the glumes, kernels, or both. In the recent years, it is emerging as a potent threat to rice crops. Seed discoloration is considered to affect the grain quality, breaking of rice grains during milling, weight loss, exports, post-harvest losses, crop yield and ultimately badly affect the economy. The present investigation was undertaken to determine the nature of seed discoloration, causes and their effect on seed quality, seed transmission, detection and identification of different seed borne fungal pathogens associated with grain discoloration of rice. In the present study, seven types of seed discoloration namely; light to dark brown dot like spot, dark purple discoloration, light pink discoloration, eye shaped spots with ash grey center, ash grey discoloration marked by brown band and black discoloration were observed. However, light to dark brown dot like spots were found to be most predominant type of seed discoloration. Pant Basmati 1 variety exhibited maximum discoloration while, Pusa Basmati 1509 had minimum discoloration. Light pink discoloration was present only in three varieties namely; Sarju-52, Pusa Sugandh-5 and Pant Basmati-1, while, eye shaped spots with ash grey center type of discoloration was not observed in varieties Govind, Pusa basmati-1509 and Pant Dhan -21. Twelve fungi namely; Alternaria alternata, F. oxysporum, F. verticillioides, Aspergillus niger, A. flavus, A. ochraceus, Nigrospora oryzae, Penicillium sp. Bipolaris tetramera, Curvularia lunata, Curvularia pallescens and Bipolaris oryzae. were found to be associated with different types of seed discoloration. Of the two incubation methods tested, agar plate method was found to be more efficient than standard blotter test. All types of seed discoloration reduced germinability, seedling vigor and resulted in increase in abnormal seedlings, seed rot and non-germinated seed. Lowest germination (33.00%) was recorded in the seeds showing ash grey discoloration marked by brown band while, highest percentage of abnormal seedlings (26.33%), seed rot (20.33%) and non-germinated seeds (24.33%) were recorded in the seeds showing black discoloration, light of dark brown dot like spots and dark purple discoloration, respectively. Of the thirteen fungi, four fungi namely; F. verticillioides, F. oxysporum, Bipolaris oryzae and B. tetramera were found to be transmitted from seed to seedlings. The study has shown that fungi associated with seed discoloration are major constraint in production of quality seeds of rice. Therefore, the farmers should be trained regarding production and post production activities for healthy, disease free quality seed and to minimize crop failure.