Abstract:
Executive Summary
The experiment was conducted at the Research Farm of Sher-e-Bangla Agricultural
University, Dhaka-1207, Bangladesh, during October, 2021 to May, 2022 to assess effect of
source-sink manipulation on leaf chlorophyll content, grain filling duration and yield and
yield components in three elite rice varieties. BRRI dhan89, BRRI dhan96 and BRRI
dhan100 were subjected to source and sink manipulations (50% flag leaf cutting, 25 and
50% spikelet removal, and control). Partial source removal (50% flag leaf) increased the
chlorophyll retention capacity in the penultimate leaf toward maturity and reverse situation
also found in case of partial sink removal (25% and 50% spikelets). Impact of manipulation
on grains number has caused the lower grain yield of all rice varieties. In response to the
spikelet removal, the grain size of BRRI dhan100 and the filled grain in the basal spikelets of
two varieties (BRRI dhan89 and BRRI dhan100) increased about 2 - 6% and 7 - 13%,
respectively. With regard to the flag leaf cutting, the grain size (1000 grain weight) of
BRRIdhan89, and the filled grain in the apical spikelets of two varieties (BRRI dhan89 and
BRRI dhan96) reduced about 2 - 6% and 2 - 8%, respectively. Less than 80% of filled grain
suggested that the grain yield of BRRI dhan89, BRRI dhan96 and BRRI dhan100 were
limited by the source activity, more than sink capacity.
