| dc.description.abstract | Two field experiments were conducted at research farm of Wheat Research Centre,
Dinajpur (25°38´ N, 88°41´ E and 38.20 m above sea level), Bangladesh, during wheat
season of 2015-16. Expt. 1: Fifty seven advanced lines compare with check varieties
BARI Gom-21 (Shatabdi), BARI Gom-26 and BARI Gom-30 and Expt. 2: Forty five
advanced lines compare with check varieties BARI Gom-21 (Shatabdi), BARI Gom-26
and BARI Gom-30. And each of the experiments consist of two time of sowing, the first
one was sown on optimum 19 November called irrigated timely sowing (ITS) and the
second was sown in 24 December 2015 was late sown condition named irrigated late
sowing (ILS) in an alpha-lattice design with two replications to evaluate the senescence
rate of genotypes under optimum and late sown condition and to find out the suitable
time of sowing for wheat genotypes.
The present study found that 1000-grain weight of wheat genotypes in exp.1 under ITS
condition ranged from 39.00 to 62.00g with mean 49.58, while it ranged from 33.00 to
54.00g with mean 43. in ILS condition. Similar results of 1000-grain weight were also
observed in exp. 2. The grain yield of wheat genotypes in exp. 1 under ITS condition
ranged between 3.03 to 6.93 ton ha-1 and mean 4.67, whereas it ranges from 2.33 to 4.62
ton ha-1 with the mean of 3.53 ton ha-1 in ILS condition. Equally results of grain yield
were also observed in exp. 2. Senescence rate of wheat genotypes in exp. 1 under ITS
condition ranged from 1.74 to 6.81% SR with mean 4.43 % SR, but it ranged from 1.94
to 7.19 % SR with the mean 5.24 SR in ILS condition. Comparable result of senescence
rate of wheat genotypes in exp. 2 was recorded as in exp. 1. Heading days had positively
correlation with senescence rate (SR) and no correlation with yield, but heading days had
significant and negatively correlated with both SR and yield under ILS condition.
Maturity days and spikelet per spike were significant and positively correlated under ITS
condition and no correlation under late sowing condition. Results showed that the
optimum sowing date had higher number of spike per meter square, spikelet per spike,
1000-grain weight and grain yield. Grain yield of 19th November sowing dates is
significantly higher than that of 24th December sowing dates. Low grain yield resulted
from stress is caused by higher temperatures that prevailed during grain filling; despite
senescence rate was increased under late sowing (ILS) condition due to the temperature
shock. | en_US |
