VARIABILITY, EPIDEMIOLOGY AND MANAGEMENT OF EARLY BLIGHT OF TOMATO CAUSED BY Alternaria solani (Ellis and Martin) JONES AND GROUT IN HIMACHAL PRADESH

Simple item page
dc.contributor.advisorGUPTA, PANKAJ
dc.contributor.authorATTRI, KAUSHAL
dc.date.accessioned2020-02-25T07:08:07Z
dc.date.available2020-02-25T07:08:07Z
dc.date.issued2020-01
dc.description.abstractABSTRACT Early blight of tomato caused by Alternaria solani is one of the most important and devastating disease of tomato which causing extensive yield losses in Himachal Pradesh. Survey of disease was conducted during 2018 and 2019 for two consecutive crop seasons. Severityof disease ranged from 30.75 to 79.28 and 34.78 to 83.25 per cent during 2018 and 2019 crop seasons in different locations surveyed and maximum disease severity (81.27%) was recorded in Kaned (Mandi) and lowest (32.77%) in Shoghi (Shimla) of Himachal Pradesh. The associated pathogen was isolated and on the basis of cultural and morphological characters, identified as Alternaria solani (Ellis and Martin) Jones and Grout. Incubation period of 144 h was recorded by spray inoculation method on leaves and 240 h and 192 h on stem and fruits by pin prick method. Twenty isolates of A. solani collected from different locations of five districts showed variation in morphological and cultural characters. RAPD molecular markers used to detect the polymorphism among these isolates were informative for detecting genetic variability and divide all the isolates into five groups, the similarity coefficient among the studied isolates was ranged from 4-67 per cent with an average of 35 percent. Under in vitro conditions temperature of 30°C and 100 per cent level of relative humidity were most favorable for germination of conidia, whereas, germ tube length was maximum at 25°C and 100 per cent level of relative humidity. Under pot culture conditions 30°C temperature and 100 per cent RH level were congenial for disease development.Simple correlation coefficient between disease severity and environmental factors viz., RH morning, RH evening, minimum temperature and cumulative rainfall were found positive and significant over the years 2018 and 2019. Partial correlation coefficient between disease severity and temperature maximum, RH morning and evening was positive but nonsignificant over two years. Multiple correlation coefficients between disease severity and studied environmental factors suggested that 87.56 per cent of disease severity was attributed by mean temperature, average relative humidity and cumulative rainfall collectively. The multiple linear regression equation showed that, a unit change in maximum temperature, relative humidity evening and morning influence the early blight disease of tomato up to an extent of 6.187, 2.371 and 0.940 in the same direction followed by -1.682 and 0.030 in opposite direction in case of minimum temperature and rainfall. Among seven bioresources tested under in vitro conditions, cow urine was highly effective at all the concentrations against the fungus followed by leaf extract of Roylea elegans (kadu). Under field conditions five foliar sprays at ten days interval of Allium satium (garlic) extract at 5 per cent concentration after initiation of disease was found most effective and gave 56.12 per cent reduction of disease. Among different systemic acquired resistance (SAR) inducers evaluated under pot culture conditions, benzothiadiazole (BTH) and ß-aminobutyric acid (BABA) were found most effective and reduced the disease severity. The activity of defence related enzymes viz. phenol, PO, PPO and PAL were maximum after 96 h and 72 h, respectively, in tomato plants treated with benzothiadiazole (BTH) and potassium dihydrogen phosphate (KH2PO4). Under field conditions two foliar sprays of benzothiadiazol (BTH) and potassium dihydrogen phosphate (KH2PO4)) were found effective against the disease which reduced the severity of disease to 71.21 and 58.40 per cent. Among different fungicides used in vitro, difenconazole, hexaconazole, copper sulphate, azoxystrobin + difenoconazole, hexaconazole + zineb, tebuconazole + trifloxystrobin, flupyram + trifloxystrobin and captan + hexaconazole were found the most effective and resulted in complete mycelial growth inhibition of the pathogen. Under field conditions foliar spray applications of hexaconazole + zineb (0.2%) and azoxystrobin + difenoconazole (0.15%), five times at ten days interval after commencement of disease were found effective which resulted in 72.37 and 69.79 per cent reduction of disease. In integrated disease management, two foliar sprays of potassium dihydrogen phosphate (1.3%) after 15 days of transplanting at seven days interval followed by six alternate foliar sprays of hexaen_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/5810143540
dc.keywordstomato , Alternaria solani, devastating disease, yielden_US
dc.language.isoenen_US
dc.pages111+XIIIen_US
dc.publisherUHF,NAUNIen_US
dc.subPlant Pathologyen_US
dc.subjectnullen_US
dc.themetomato , Alternaria solani, devastating disease, yielden_US
dc.these.typePh.Den_US
dc.titleVARIABILITY, EPIDEMIOLOGY AND MANAGEMENT OF EARLY BLIGHT OF TOMATO CAUSED BY Alternaria solani (Ellis and Martin) JONES AND GROUT IN HIMACHAL PRADESHen_US
dc.typeThesisen_US
Files
Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
PDF Ph.D. Thesis Kaushal Attri (Plant Pathology).pdf
Size:
9.33 MB
Format:
Adobe Portable Document Format
Description:
PLANT PATHOLOGY
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Theses
Load more