Abstract:
The experiment was conducted during the period from May 2011 to April 2012
to find out the effect of seed infection levels and plant population density on
leaf blight severity and yield of wheat. Three population density viz. 200
seed/m/, 300 seed/m2 and 400 seed/nr' and six seed infection levels viz. 0%,
5.1 - 15%, 15.1 - 25%, 25.1 - 35%, 35.1 - 45% and 45.1-60% were used.
Maximum leaf spot severity in flag leaf stage (0.36), panicle initiation stage
(0.64), flowering stage (1.57), milk stage (1.84) and hard dough stage (2.30)
was found in the interaction between sowing seeds @ 400 seeds/rrr' with 45.160%
seed infection level. In every growth stage of the plant significantly lower
leaf blight severity was recorded in the interaction between 200 seeds/nr' with
sowing of 0.0% infected seeds. Similar trends in disease severity were recorded
on penultimate leaf in above mentioned growth stage. Significantly higher
number of grains/ear (58.00) and healthy grains/ear (55.67) was recorded under
the treatment TI (0% seed infection) with a seed rate of 200 seeds/m/. Lower
number of diseased grains/ear (2.33) were recorded under the treatments T6
with 400 seeds/m/ and Tl with 200 seeds/m'. Weight of diseased grains/ear
ranged from 0.07 g to 0.75 g where the lowest value was recorded under Tt X
200 seeds/nr' treatment combination. Significantly higher (45.60) grain weight
of 1000 seeds was recorded under the treatments TI (0% seed infection) with a
seed rate of 200 seeds/mi. Straw yield under different treatment combinations
ranged from 3.17-4.21 t/ha where the highest straw yield was obtained under
the treatment combination of TI X 200 seeds/mi. Grain yield was significantly
the highest (3.43 t/ha) when healthy seeds (0% infection) were sown @ 200
seeds/m'.
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 (MS)
IN
PLANT PATHOLOGY
