TITLE:
Competitiveness of Winter Rice Varieties against Weed under Dry Direct Seeded Conditions
AUTHORS:
A. N. M. Atikur Rahman, A. K. M. Mominul Islam, Md. Altamas Arefin, Md. Rashedur Rahman, Md. Parvez Anwar
KEYWORDS:
Aerobic Rice, Rice-Weed Competition, Dryland Farming, Weed Pressure, Weed Management
JOURNAL NAME:
Agricultural Sciences,
Vol.8 No.12,
December
29,
2017
ABSTRACT:
Aerobic rice or dry direct seeded rice is highly vulnerable to weeds because of
lack of “head start” over weeds and standing water layer to suppress weeds.
The risks of chemical control and the huge cost involvement in mechanical
control demand an eco-friendly and cost-effective integrated weed management.
Weed competitive rice cultivar may be considered as a viable tool for
integrated weed management. In these circumstances, an experiment was designed
to evaluate weed competitiveness of some selected winter rice varieties
under aerobic soil conditions. The study was conducted during dry season
(February to June) 2016 at the Agronomy Field Laboratory and Weed Management
Laboratory, Bangladesh Agricultural University, Mymensingh. Fourteen
rice varieties namely, BRRI dhan28, BRRI dhan29, BRRI dhan47, BRRI
dhan50, BRRI dhan55, BRRI dhan58, BRRI dhan59, BRRI dhan67, Binadhan-5, Binadhan-6, Binadhan-8, Binadhan-10, BRRI hybrid dhan3 and Agrodhan-14 were grown under weedy and weed-free conditions. Plots with no rice were
also maintained to observe the natural growth of weed in absence of rice. The
experiment was conducted with split-plot design with three replications.
Weeding regime was allocated in main plot and rice variety was allocated in
sub-plot. Results showed that rice varieties varied widely in their yield performances
and weed competitiveness. Among rice varieties, BRRI dhan59 allowed
the minimum weed growth (19.2 g m-2) while Binadhan-5 allowed the
maximum weed growth (62.8 g m-2). Grain yield ranged from 1.85 t ha-1 (BRRI dhan55) to 3.92 t ha-1 (Binadhan-5) under weed-free condition and
between 0.41 t ha-1 (BRRI dhan55) and 2.06 t ha-1 (BRRI dhan59) under weedy
condition. Weed inflicted relative yield loss ranged from 43.4% to 82.1%
among the varieties. BRRI dhan59 allowed the least yield penalty (43.4%) while Binadhan-5 had the maximum yield penalty (82.1%) due to weed competition.
Although Binadhan-5 is the most productive variety (3.92 t ha-1) for
aerobic culture but its weed inflicted relative yield loss is higher (82.1%) than
many other varieties with low yield potential. On the other hand, BRRI
dhan59 appeared as the most weed competitive variety (only 43.4% relative
yield loss) with productivity of 3.84 t ha-1. Therefore, weed competitive variety
should be considered as a vital tool while designing integrated weed management
system for aerobic rice.