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M. Sc. Dissertations

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20096
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Subject: Plant Pathology × End date: 2009 × Start date: 2009 ×
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Now showing 1 - 6 of 6
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    ThesisItemOpen Access
    Selection and characterization of chickpea calli tolerant to ascochyta rabiei (Pass.) Labrousse
    (CCSHAU, 2009) Prabhat Kumar; Sangwan, M.S.
    Present study was carried out with the objective to develop efficient protocol for establishment of callus culture derived from hypocotyl explant, to evaluate the callogenic response of chickpea genotypes against different concentrations of culture filtrate of Ascochyta rabiei and biochemical characterization of calli showing resistance to culture filtrate. Among different media used for callus induction, MS medium supplemented with IAA (2.5 mg/l) & BAP (0.5 mg/l) [C4] gave maximum callus induction (100 %), also dark green and fragile callus. Callogenic development was more in resistant [E100Y(m)] and moderately resistant (Gaurav) genotypes as compared to susceptible genotypes Pb-7 and L550, when exposed to different concentrations of A. rabiei culture filtrate. Addition of 20 % concentration of culture filtrate in callus induction medium proved to be lethal for most of chickpea genotypes calli. Therefore, sub lethal concentrations up to of 15 % can be used for in vitro screening for resistant calli. Increase in concentrations of culture filtrate resulted in decrease of fresh as well as dry weight of calli derived from all genotypes. Total soluble sugars and reducing sugars were higher in calli of resistant [E100y (m)] and moderately resistant (Gaurav) genotypes as compared to susceptible genotypes (Pb-7, L 550). Level of phenols, flavanols and soluble proteins were also higher in the calli of all genotypes with increased in concentrations of culture filtrate. Activities of all the three enzymes viz. polyhenol oxidase, peroxidase and catalase increased in response to increase in concentrations of culture filtrate. But activities of polyphenol oxidase and peroxidase were higher in moderately resistant and resistant genotypes while catalase activity was higher in susceptible genotypes.
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    ThesisItemOpen Access
    Selection and characterization of rapeseed and mustard calli tolerant to sclerotinia sclerotiorum (Lib.) de bary
    (CCSHAU, 2009) Watpade, Santosh Ganpat; Mehta, Naresh
    Present study was carried out with the objective to investigate the callogenic response of rapeseed-mustard species to culture filtrate of Sclerotinia sclerotiorum, oxalic acid and to characterize the calli showing tolerance to culture filtrate along with non-selected calli, based on few biochemical parameters. To study the callogenic response of rapeseed-mustard species to S. sclerotiorum, different concentrations of culture filtrate and oxalic acid were added in MS medium supplemented with NAA 1 mg-1+ BAP 1 mg-1. NAA 1 mg-1+ BAP 1 mg-1 was found most suitable for callus induction to all the four species viz., B. juncea cv. RH-30, B. alba cv. Local, B. napus cv. GSH-1 and B. carinata cv. HC-9002. Per cent callus formation in response to S. sclerotiorum culture filtrate and oxalic acid was more in B. carinata cv. HC-9002 than other Brassica species. Reduction in shoot length and total seedling length due to presence of oxalic acid in germination media was also minimum in B. carinata cv. HC-9002 than other Brassica species. In vitro callus screening with S. sclerotiorum culture filtrate and oxalic acid revealed a similar behavior with field reactions IV of the Brassica species to the disease. As well as seedling screening on germination media amended with oxalic acid also showed correlation with field reactions. Since twenty per cent concentration of culture filtrate was lethal to some genotypes except B. napus cv. GSH-1 and B. carinata cv. HC-9002 and 10mM concentration of oxalic acid is lethal for all species, 15% concentration of culture filtrate and 5mM concentration of oxalic acid can be used for in vitro screening for selection of tolerant species. Increase in concentration of culture filtrate and oxalic acid resulted in decrease of fresh as well as dry weights of calli derived from all the species. Oxalic acid also caused reduction in shoot length, root length and total seedling length of rapeseed-mustard seedlings, 10 mM oxalic acid concentration can be used for in vitro seedling screening and shoot length was better parameter of susceptibility. Total soluble sugars and reducing sugars were high after selection with S. sclerotiorum culture filtrate in calli of B. napus cv. GSH-1 and B. carinata cv. HC-9002 but other species showed less sugar contents. Level of phenol and flavanol were high in all the species after selection. Activity of all the three enzymes viz., polyphenol oxidase, peroxidase and catalase increased with response to increase in concentration of culture filtrate.
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    ThesisItemOpen Access
    Epidemiology of sclerotinia rot of Indian mustard
    (CCSHAU, 2009) Narwal, Sameer; Anil Kumar
    With a prime objective to investigate the role of environmental factors in epidemiology of Sclerotnia rot of Indian mustard and to diagnose the disease in field condition using spectral approach. Two mustard varieties viz. RH 30 and Varuna were sown on four dates of sowing last week of September, second week of October, last week of October and second week of November during the rabi season 2008-09. Disease incidence was recorded at weekly intervals after initiation of disease in all the treatments. The weather data of the corresponding periods were taken from the Agrimeterological. Observatory situated at Research farm of the Chaudhary Charan Singh Haryana Agricultural University, Hisar. The reflected radiance values in different IRs bands were measured with the help of Ground Fruth Radiometer (GTR) over crop surface in all the treatments under inoculated and uninoculated sites from 10.00 a.m. to 12.00 noon. The reflectance values in all form sands were also measured over Barium sulphate plate (100% reflection) for using as standard reflectance values over a surface. The per cent reflectance values were computed by taking the ratio of radiance value over a crop surface and standard radiance value over a Barium xii sulphate plate. These spectral reflectance values in IRs bands were used for computing spectral indices. Vegetation index, normalized difference vegetation index, perpendicular vegetation index and disease water stress indices on the same days of disease observations. The maximum disease incidence was recorded in first date of sowing and it decreased drastically with delay in sowings. The maximum incidence in first date of sowing was 27.6 and 25.6 per cent in mustard varieties RH-30 and Varuna, respectively. The weather parameters : maximum temperature, minimum temperature, morning relative humidity, evening relative humidity, sunshine hours and wind speed were correlated with disease incidence by pooling the data first for all the environments and then for both the varieties. The correlation coefficients ranged from 0.17 to 0.78 in both the cultivars. The disease incidence was directly associated with maximum temperature, morning and evening relative humidity whereas, incase of sowing environments, sunshine hours also played significant role in disease development. The regression model based on significant weather parameters, explained the variability in stem rot incidence upto 98 per cent, during different sowing environments. The reflectance values were higher in visible bands over healthy (uninoculated) crop in comparison to diseased (inoculated) crop. The reverse trend was observed in case of infra red reflectance over healthy and diseased crop surface. The vegetation indices values were higher in healthy crop as compared to diseased crop except disease water stress index-4. The correlation coefficients of vegetation indices varied from -0.73 to -0.74 in RH-30 and from -0.75 to -0.79 in Varuna. The regression model based on significant vegetation indices explained the variability in disease incidence upto 81 and 86 per cent in mustard varieties RH-30 and Varuna, respectively. The spectral approach can be used as diagnostic tool for stem rot incidence in mustard crop under field condition.
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    ThesisItemOpen Access
    Studies on characterization of important viral diseases of onion and their management
    (CCSHAU, 2009) Pawan Kumar; Dhawan, Poonam
    The present investigations on symptomatology, transmission, host range, host reaction, detection and eco-friendly management of onion yellow dwarf virus (OYDV) and iris yellow spot virus (IYSV) diseases were conducted on onion crop cv. Hisar-2 during Rabi seasons 2007-08 and 2008-09 at the experimental farm, Department of Plant Pathology, CCS Haryana Agricultural University, Hisar. OYDV disease appeared in the form of crinkling and faint chlorotic stripes on the leaves of the bulb as well as seed crop. Some plants showed prominent yellow stripes on leaves and scapes of seed crop. Later on the scapes showed twisting and bending and this incidence reached at 68% in seed crop. Iris yellow spot virus showed hay coloured and water soaked spots on the leaves of bulb as well as the seed crop. The spots were found in different shapes and sizes such as diamond-shaped and irregular spots on the scapes of seed crop. These spots coalesced and led to drying. The mechanical transmission of OYDV (68.88%) and IYSV (62.5%) were successfully achieved. Nymphs of aphids such as Aphid craccivora, A. gossypii and Myzus persicae could transmit OYDV to 46.87, 53.31 and 62.5 per cent, respectively. IYSV was transmitted upto 54.17% by nymphs of Thrips tabaci. Host range of OYDV was found to be very narrow only to onion and garlic cultivars whereas, IYSV had a wide host range. OYDV and IYSV were detected by DAS-ELISA in infected onion plants. The incidence of OYDV (83.22%) and IYSV (89.97%) were recorded in bulb crop which caused losses of 14.62% and 9.85% in bulb weight due to OYDV and IYSV, respectively. A high incidence of OYDV (90.65%), IYSV (88.25%) and lodging (75.68%) was recorded in seed crop. The reduction in seed yield (53.84%) was observed maximum in plants infected with OYDV grade A and least (6.6%) in OYDV grade D. A reduction of 50% in seed yield was recorded with IYSV disease with a substantial reduction in seed quality. None of the management strategies tried was effective for reducing OYDV incidence whereas incidence of IYSV (67.24%) and lodging (40.27%) was reduced in late planted crop i.e. 12th Nov., 2009. But at the same time seed yield was also reduced 34.22% due to late planting. None of the varieties/collections was found resistant to onion yellow dwarf virus and iris yellow spot virus diseases. All the varieties/collections were found highly susceptible to both diseases. There is a need to screen more germplasm lines to find sources of resistance to these viral diseases.
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    ThesisItemOpen Access
    Studies on powdery mildew of fenugreek caused by erysiphe polygoni DC
    (CCSHAU, 2009) Rajesh Kumar; Mehra, Rakesh
    The Studies on powdery mildew of fenugreek caused by Erysiphe polygoni DC" were conducted in the Departments of Plant Pathology and Vegetable Science, CCS Haryana Agricultural University, Hisar during winter (rabi) season of 2008-09. The experiments were laid out in RBD in field and CRD in lab conditions. Powdery mildew of fenugreek generally occurs during flowering and pod formation stage in severe form. Seed yield losses due to powdery mildew varied between 18.8 and 20.4 per cent in variety Hisar Sonali and 19.4-22.5 per cent in variety Hisar Suvarna in both greens cutting and non greens cutting under unprotected conditions. Out of 118 germplasm lines/varieties of fenugreek screened against powdery mildew under field and screen house conditions, none was found highly resistant. Only two genotypes namely NDM-1 and RMt-351 were found resistant under field conditions. However, under screen house conditions these genotypes were moderately resistant. Four genotypes viz., Am-187, HM-273, Local Hisar-3, NDM-9 were moderately resistant both under field and artificial inoculation conditions. Out of five dates of sowing early sown (4th October) and late sown (5th December) crop showed less disease severity as compared to 19th October, 4th November and 20th November sown crop. Maximum disease severity was in the crop sown on 4th November in Hisar Sonali, Hisar Suvarna and HM-65 varieties. Among the five varieties highest disease severity was observed in Hisar Sonali variety and lowest disease severity on variety HM-350 on all the dates of sowing. Maximum temperature range of (23.8-31.7 oC) and minimum of (7.9-14.6 oC), relative humidity morning (91.4–86.9%) and evening (53.3–38.1 %) were most congenial for the disease progression. Regression equations on relationship between disease development and weather parameters have been developed for five varieties. Among the seven plant extracts evaluated against Erysiphe polygoni, neem, ginger and garlic extracts were effective both under in vitro and in vivo conditions, however, the efficacy was comparatively less in comparison to fungicides which provided more than 95 per cent disease control. Out of eight fungicides evaluated hexaconazole, propiconazole and dinocap provided disease control around 99 per cent and also increase seed yield significantly.
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    ThesisItemOpen Access
    Epidemiology and management of stemphylium blight of onion (Allium cepa L.) caused by stemphylium vesicarium (Wallr.) simmons
    (CCSHAU, 2009) Vinod Kumar; Gupta, Anil
    In epidemiological studies temperature (maximum) 20.3 to 250C, temperature (minimum) 0.3 to 4.00C, relative humidity (morning) more than 82 to 89 per cent, relative humidity evening 25 to 28 per cent have been observed congenial for the progression of the disease. The regression analysis of disease severity with weather variables showed that temperature (maximum ) and temperature (minimum) were most contributing factors with R2 values 0.91,0.94,0.94 and 0.92 in four dates of transplanting respectively. The correlation coefficient analysis of disease severity concluded that temperature (Maximum) and temperature (minimum) were significant and positively correlated with disease development. However, relative humidity (evening) was found to be non significant, relative humidity (morning) also had a role in disease development. The stepwise regression analysis showed that all the five weather variables produced maximum R2 value in all the four dates of transplanting (0.95-0.98). However the two variables temperature (maximum) and temperature (minimum) were most contributing factor and produced maximum R2 value in all the four dates of transplanting (0.91-0.94). In survival experiment during the month of December no viable spores could be seen in the debris kept under field and lab conditions. However the survival of the pathogen could be noticed in freeze conditions only upto 17.5 per cent. Seven varieties/lines /genotypes were tested against Stemphylium blight of onion. None of these varieties/lines /genotypes showed resistance against Stemphylium blight of onion. The effect of leaf extracts on mycelial growth of the fungus under in vitro conditions revealed that neem leaf extract was best with 71.01 per cent inhibition. Among the fungicides/chemicals mancozeb 0.2 per cent gave highest (76.19 per cent ) disease control. Benefit cost ratio was also calculated on the basis of increase in yield over control and found that mancozeb proved better. However , among the non-traditional chemicals neem leaf extracts or neem seed extracts gave highest benefit cost ratio.