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M. Sc. Dissertations
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ThesisItem Open Access Influence of stripe disease [Drechslera graminea (Rabenh.) Shoemaker] on physio-biochemical parameters of barley and its management(CCSHAU, 2011) Satish Kumar; Karwasra, S.S.Stripe disease of barley caused by Drechslera graminea (Rabenh.) Shoemaker is a widely distributed disease in many barley grown parts of the world, but it has assumed more importance with the introduction of some new high yielding varieties. The present investigations were undertaken during 2007-08 and 2008-09 crop seasons with a view of elicit information on effect of disease on biochemical and physiological parameters particularly in vitro dry matter digestibility, protein content, malt extract, chlorophyll content, leaf area, photosynthesis, stomatal conductance and transpiration. Effect of disease on yield parameters, search for new sources of resistance, effect of sowing dates on disease incidence and efficacy of fungitoxicants in controlling the disease. In vitro dry matter digestibility (IVDMD) decreased and total protein (%) increased in barley plants having disease, while malt extract (%) was more in grains collected from healthy plants. Stripe infection resulted in reduction of all the physiological parameters at both the stages i.e. 35 days and 50 days after disease appearance. Stripe disease had also the adverse effect on all the growth and yield parameters. Maximum reduction was in tillers/plant i.e. 69.97% while the reduction in yield /plot (kg) was 29.03%. Six rowed barley lines/varieties when compared with two rowed barley lines/varieties on the basis of mean infection value, two rowed lines/varieties had more resistance than six rowed. Grouping on the basis of mean infection value in six rowed barley 3 lines / varieties were highly resistant, while in two rowed 4 lines / varieties were highly resistant. In early sown crop i.e. 15th October there was no disease but in late sowings there was disease. Soil moisture had the positive correlation with disease incidence with values 0.83 and 0.84. Five fungitoxicants evaluated were significantly effective in controlling the disease at 0.1 and 0.2 per cent doses. Raxil-2DS at lower dose (0.1%) was quite effective with 2.75% disease on plant and 1.08% tiller basis. However, Raxil-2DS and Vitavax-75WP at 0.2% were very effective and provided maximum disease control on plant and tiller basis. Maximum yield was also obtained in both the treatments.ThesisItem Open Access Studies on management of brown spot disease of rice (Oryza sativa L.) caused by Drechslera oryzae(CCSHAU, 2011) Satish Kumar; Dharam SinghPresent investigation on “Studies on management of brown spot disease of rice (oryza sativa L.) caused byDrechslera oryzae” was carried out in field conditions.Drechslera oryzae was isolated from the leaf showing typical brown spot symptoms to carry out management studies. Survey of rice growing areas of Haryana was conducted at dough stage of crop to record incidence of brown spot disease. Maximum disease incidence was recorded in scented rice in the district of Karnal and Panipat. To identify source of resistance, a collection of 140 genotypes were evaluated for their reaction to Drechslera oryzaeunder artificial epiphytotic conditions. Out of 140 genotypes, only two viz., IR 79216-141-1-3-3, KJT-3-2-7-7-2 and four viz., HKR 08-63, OM 5240, OR 2329-22 and RP Bio-110 were found highly resistant and resistant respectively, which can be utilized in resistant breeding programme. The effectiveness of 9 fungicides and 7 botanicals were tested in in vitro against mycelial growth inhibition and as foliar spray to test against all the three phases of brown spot disease viz., leaf spot severity, stalk and neck rot incidence. Invitro growth inhibition test revealed that the fungicides and botanicals varied considerably in their toxicity to Drechslera oryzae. The EC50 values of fungicides ranged between 58.6 to 998.6 ppm a.i. Propiconazole was most inhibitory with EC50 value of 58.6 ppm a.i. closely followed by strobulin having EC50 value of 68.2 ppm a.i. Tebuconazole was least inhibitory with EC50 value of 998.6 ppm a.i. The EC50 values of botanicals ranged from 6327.2 to14590ppm a.i. Mentha was most inhibitory with EC50 value of 6327.2 ppm a.i. closely followed by Arjun tree with EC50 value of 6555.4 ppm a.i. Pipal leaves extract was least inhibitory with EC50 value of 14590 ppm a.i. Propiconazole also proved most effective in controlling all the three phases of brown spot disease and increasing grain yield followed by strobulin when applied as foliar spray.Tebuconazole proved least effective. Amongst botanicals, Arjun tree leaf extract proved most effective in controlling disease and increasing grain yield followed by Mentha and Achook.