Abstract:
Purple blotch of onion samples collected from different onion growing regions of Bangladesh and studied
their cultural, morphological, pathogenic and molecular characterization. Colony
color varied between light to dark olivacious and grayish white. Shapes of
colonies were irregular, regular with and without concentric ring. Margin of
colonies were entire, irregular and wavy with effuse, fluffy and velvety texture.
Isolates impregnated media with color ranging between grey to brown. Growth
rate of isolates was between 2.43 to 3.95 mm/day with fast growth in isolate
DSTR 02 and least in MMBH. Morphological variation in conidia production was
between 7.720×10
3
to 47.02×10
3
per mm
2
with sporulation time 3.33 to 11.00
days. The conidial shape was straight to curve with light to deep brown color.
Conidial septation ranged from 3.00 to 6.00 × 1.00 to 2.00 with size from 11.20 to
39.20 × 4.76 to 11.43 µm. Isolates shown variations in lesions size exhibited the
pathogenic variation exist in the environment. In molecular study no band were
found by using seven
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
SEMESTER: JULY-DECEMBER, 2013
