Please use this identifier to cite or link to this item: http://krishikosh.egranth.ac.in/handle/1/5810029827
Authors: Sangeetha K.D
Advisor: Dr.S.A.Ashtaputre
Title: STUDIES ON VARIABILITY AND MANAGEMENT OF Alternaria spp. CAUSING LEAF BLIGHT OF COTTON
Publisher: University of Agricultural Sciences, Dharwad.
Language: en_US
Type: Thesis
Agrotags: null
Keywords: STUDIES ON VARIABILITY AND MANAGEMENT OF Alternaria spp. CAUSING LEAF BLIGHT OF COTTON
Abstract: Cotton is one of the most ancient and important commercial crops next only to food grains. A survey carried out during kharif 2013 revealed the maximum incidence of Alternaria leaf blight of cotton in Dharwad. Among different crop stages, maximum mean incidence was recorded in boll initiation stage. Bunny Bt and NAMCOT.612 were more susceptible to Alternaria blight. Bt genotypes recorded higher amount of chlorophyll 'a', chlorophyll 'b' and total chlorophyll, total sugar, reducing sugar and non-reducing sugar content and lower amount of total phenol and gossypol content when compared to non-Bt genotypes. Among the ten isolates, two resembled with Alternaria macrospora, five showed no resemblance with Alternaria macrospora and three isolates resembled with Alternaria alternata morphologically with conidial measurements described by Ellis M. B. Sixteen days was required for Alternaria macrospora to attain maximum dry mycelial weight. Among the ten isolates, Chandanamatti (A6) recorded maximum mean radial growth. Majority of the isolates showed moderate to excellent sporulation and irregular grey colonies. Raised mycelial growth was mainly observed in A2, A3, A5 and A7, whereas medium raised mycelial growth were seen mainly in A1 and A10. Sectoring was present in isolates viz., A1, A4, A5, A8 and A10. The inoculation study conducted to know the transmission property of all the ten isolates revealed that the pathogen got transmitted to cotton crop. Specific primers for Alternaria macrospora and Alternaria alternata showed rDNA amplicon of all the ten and three isolates at 442 bp and 320 bp, respectively. In in-vitro evaluation of systemic fungicides, Hexaconazole, Propiconazole and Hexaconazole 4% + Zineb 68% showed cent per cent inhibition at all the concentrations (0.05%, 0.075% and 0.1%). In field evaluation, Hexaconazole @ 0.1% showed best disease control with high yield (1536.76 kg/ha).
Subject: Plant Pathology
Theme: STUDIES ON VARIABILITY AND MANAGEMENT OF Alternaria spp. CAUSING LEAF BLIGHT OF COTTON
These Type: M.Sc
Issue Date: 2014-06
Appears in Collections:Thesis

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