| dc.description.abstract | A field experiment was design to evaluate the effect of some varieties and dates of
sowing on the Bipolaris leaf and head blight disease of wheat caused by Bipolaris
sorokiniana at the Central Farm of WRC, BARI, Noshipur, Dinajpur duing the period of
2016-17. There six varieties viz. BARI Gom 21 (Shatabdi), BARI Gom 26, BARI Gom
27, BARI Gom 28, BARI Gom 29 and BARI Gom 30, and five dates of sowing (DAS)
were viz. November 15, December 01, December 15, January 01 and January 15. The
experiment was laid out in a Spilt Plot Design with three replications. The variety was
set in the main plot and the sowing date was placed in sub plot. Data were collected on
percent leaf blight severity and percent infected head blight at 35, 45 and 55 DAS and
seed yield data after processing. The effect of variety on percent leaf blight severity of
wheat at different days after sowing were found significant. The final data on leaf blight
seveity at 55 DAS, the highest percent leaf blight severity (68.09%) was found in BARI
Gom 30 and lowest (38.73%) was recorded in BARI Gom 21 whereas in case of sowing
date, the highest (59.73%) leaf blight severity was found in Jan 01 while the lowest
(52.49%) was recorded in Nov 15. In the percent head blight infection, the highest
(5.06%) head blight was found in BARI Gom 28 and the lowest (3.56%) infected head
blight was recorded in BARI Gom 21. Response to date of sowing, the highest (5.17%)
infected head blight was found in Jan15, while the lowest (3.23%) infected head blight
was recorded in Nov 15. The seed health test by dry inspection and blotter method were
done for each variety and each date of sowing. 400 seeds were taken as representative
sample of each variety and tested their health status by dry inspection method and found
that the highest percent of infected seeds 5.15% was found in seed sample of BARI Gom
29 the lowest in BARI Gom (26 3.51). In connection of five dates of sowing, the highest
percent of infected seeds (4.69.15%) was found in seed sample of Dec. 15 and the lowest
(4.04%) in Nov. 15. The seed samples tested by blotter method, the highest percent of
infected seeds (3.60%) was found in seed sample of BARI Gom 28 and the lowest
(2.53%) in BARI Gom 27. Considering the date of sowing, the highest percent of
infected seeds 3.37% was found in Dec. 15 and the lowest (2.87%) in Nov. 15. In yield
parameter, the highest yield was recorded in BARI Gom 26 (59.54 kg/plot) followed by
BARI Gom 21 (56.30 kg/plot). The lowest grain yield was found in BARI Gom 27
(53.87kg/plot). Regarding the date of sowing, the highest yield was found in Nov. 15
(68.73kg/plot) sowing and the lowest in January 15 (48.86kg/plot). In the regression
coefficient and R2 value between the leaf blight, head blight, seed infection and yield as
dependent and sowing date as independent variables were assessed and found some
known and many unknown factors might be involved in disease development. These
research findings in turns concluded overall that varieties have little significant
difference in disease severity but BARI Gom 21 performed better whereas date of
sowing has strong and closer links in disease severity where November 15 may be
employed to follow. | en_US |
