Abstract:
A study was conducted to observe the post harvest diseases of some selected salad
vegetables and to identify their causes. The experiment was conducted in the MS
Laboratory of Department of the Plant Pathology, Faculty of Agriculture, Sher-eBangla
Agricultural University during the period from March, 2019 to March, 2020.
Samples were collected from local markets of Dhaka city. In this study, seven
different fungal species and four different bacterial strains were isolated. Aspergillus
rot (Aspergillus niger and Aspergillus flavus), cottony soft rot (Sclerotinia
sclerotiorum), fusarium rot (Fusarium sp), sour rot (Geotrichum candidum),
anthracnose (Colletotrichum capsici), green mold (Trichoderma sp) and bacterial soft
rot (Serratia marcescens, Bacillus sp and Pseudomonas sp) diseases were identified.
Fungi were isolated by growing them in moist chamber and PDA medium. Bacteria
were isolated by dilution plate method and growing them in NA medium by spread
plate method and streak plate method. Bacteria were identified by studying the
morphological and cultural characteristics and performing several biochemical tests
like Gram-staining test, KOH solubility test, oxidase test, catalase test, motility test,
citrate utilization test, casein hydrolysis test, lactose fermentation test, sucrose
fermentation test, dextrose fermentation test. Bacillus agar and citrimide agar medium
were used to separate Bacillus and Pseudomonas, respectively. Pathogenicity test of
some pathogens were also performed. Identification of the bacteria from cucumber
was further confirmed by extracting DNA from the bacterial cultures. The samples
were subjected to PCR using 27F and 1492R primers. The D1/D2 of 16S rDNA
sequences of Serratia marcescens isolates were submitted to NCBI for deposition in
the GenBank and accession number. The provided accession number MW404210 for
Serratia marcescens strain SAU-1. Effects of different storage containers on different
vegetables and their microbial growth were also observed.
Description:
A Thesis
Submitted to the Department of Plant Pathology
Sher-e-Bangla Agricultural University, Dhaka
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE (M.S.)
IN
PLANT PATHOLOGY
