EFFECT OF SEEDLINGS PER HILL AND WEED MANAGENMENT STRATEGIES ON GROWTH AND YIELD OF BRRI dhan50

Abstract

A field experiment was conducted at the farm of Sher-e-Bangla Agricultural University (90º33´ E longitude and 23º77´ N latitude), Dhaka, Bangladesh during November 30, 2012 to May 05, 2013 in boro season with a view to find out the performance of BRRI dhan50 with different seedlings per hill under different weed management strategies. The experiment was carried out with four plant population densities i.e. 2 seedlings hill-1 (P1), 4 seedlings hill-1 (P2), 6 seedlings hill-1 (P3) and 8 seedlings hill-1 (P4) in the main plot and five weed management strategies viz. no weeding (control) (W0), two hand weeding at 20 and 35 DAT (W1), Weeding by BRRI rice weeder at 20 and 35 DAT (W2), Topstar 400SC (Oxadiargyl 400 g L-1) @ 100 ml ha-1 as pre-emergence (W3) and Sunrice 150WG (Ethoxysulfuron 150 g L-1) @ 185 ml ha-1 as post-emergence herbicide (W4) in the sub plot in split plot design. Twenty two different weed species found in the field among which Cyperus michelianus (36.73%) at 30 DAT, Cyperus esculentus (25.13%) and Alternanthera sessilis (21.54%) at 60 DAT, Fimbristylis miliaceae (19.50%) at 90 DAT were dominant. Application of Sunrice 150WG showed highest weed control efficiency at 30 DAT 80.94% and 61.52% at 60 DAT. Two seedlings hill-1 (P1) showed highest weed control efficiency (58.92%) at 30 DAT and 4 seedlings hill-1 (P2) also showed highest weed control efficiency (39.18%) at 60 DAT. Both seedlings per hill and weed management strategies significantly influenced the growth, yield and yield contributing characters of BRRI dhan50. The result showed that 2 seedlings hill-1 (P1) performed highest grain yield (5.70 t ha-1), straw yield (7.81 t ha-1), biological yield (13.52 t ha-1) and harvest index (42.06 %) and post-emergence herbicide Sunrice 150WG control weeds very successfully resulting highest growth and yield contributing characters of rice. Among the weed management strategies Sunrice 150WG (W4) showed best in producing highest grain yield (5.36 t ha-1), straw yield (7.42 t ha-1), biological yield (12.77 t ha-1) and harvest index (41.63%). The interaction between seedlings per hill and weed management strategies showed that 2 seedlings hill-1 with Sunrice 150WG appeared as a good combination in producing highest grain yield (6.81 t ha-1), straw yield (8.69 t ha-1), biological yield (15.49 t ha-1) and harvest index (43.96%) in BRRI dhan50.