Screening of weed-competitive variety of transplant aman rice, its optimum nitrogen dose and plant spacing for effective weed management

Two experiments were conducted at the Bangladesh Agricultural University, Mymensingh to screen

out the highly competitive variety of transplant aman rice and to find out its appropriate weed

management practices. Twelve varieties namely BR22, BR23, BRRI dhan30, BRRIdhan31,

BRRIdhan32, BRRIdhan34, BRRIdhan37, BRRIdhan38, BRRIdhan39, BRRIdhan40, Binasail and

Binadhan-4 were grown in presence and in absence of the weed Echinochloa crusgalli. Monoculture

of the weed was also maintained. The aggressivity of rice varieties was measured against the weed.

The study was further expanded in finding out the best nitrogen dose and plant spacing for providing

the selected variety with more competitiveness. Finally the yield performance of the selected rice

under the selected management practices was assessed. Variety BRRI dhan30 was found to be the

most competitive (aggressivity = 0.43) and Binadhan4 was the least competitive variety (aggressivity

= 0.05). The nitrogen dose of 80 kg N ha-1

competitiveness (aggressivity = 0.60) to the variety under the condition of experiments. The variety

BRRI dhan30 also produced the highest grain yield (5.2 t ha-1

due to weed competition under the management practices.

and plant spacing of 25 cm X 15 cm rendered the best