Abstract:
The experiment was conducted at MS Laboratory, Department of Plant
Pathology, Sher-e-Bangla Agricultural University, Dhaka-1207 during the
period of August 2019 to March 2020 to isolate, identify, and characterize the
causal agents responsible for the post-harvest spoilage of some selected root and
tuber crops. Potato, sweet potato, radish and carrot were used as samples.
Infected samples were collected from different markets in Dhaka city. The postharvest
fungi
were
isolated
on
PDA
medium
following
tissue
planting
method.
Five
different
fungi genera were isolated and identified viz. Aspergillus niger,
Geotrichum candidum, Rhizopus stolonifer, Fusarium spp. and Penicillium
digitatum. Of these, Fusarium spp. has the highest percentage of frequency of
occurrence in potato, carrot and radish. In carrot, Aspergillus niger showed more
frequency of occurrence than Geotrichum candidum but in case of sweet potato,
the occurrence of Rhizopus stolonifer was found to be more than Penicillium
digitatum. Pathogenicity tests revealed that all the isolated fungi were pathogenic
to their respective host as post-harvest pathogens. Effect of different media and
temperature on growth of isolated fungi were studied. On PDA media, the
highest radial mycelial growth (4.06 cm) at 8 DAI was recorded in Aspergillus
niger (carrot) which was statistically similar with Rhizopus stolonifer (sweet
potato) whereas, the lowest radial mycelial growth (2.54 cm) was recorded in
Fusarium oxysporum (radish). The highest radial mycelial growth was observed
in PDA followed by CDA media. Most of the isolated fungi showed the highest
growth rate at 30℃ temperature, whereas, the growth rate of Rhizopus stolonifer
was found the highest at 25℃ temperature.
Description:
A Thesis
Submitted to the Faculty of Agriculture,
Sher-e-Bangla Agricultural University, Dhaka,
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE
IN
PLANT PATHOLOGY
