EFFICACY OF BRASSICA VARIETIES TO CONTROL WEEDS IN WHEAT

Abstract

The experiment was conducted at the Agronomy research field, Sher-e-Bangla Agricultural University, Dhaka from October, 2011 to March, 2012 to find out the efficacy of Brassica varieties to control weeds in wheat. The experiment was conducted in completely randomized block design with three replications. The experiment consisted of 12 treatments T1 : No Brassica + no biomass (Control), T2 : No Brassica + biomass of 5 varieties , T3 : Brassica (Tori 7) without biomass, T4 : Brassica (Tori 7) with biomass of same variety, T5 : Brassica (BARI sarisha - 8) without biomass, T6 : Brassica (BARI sarisha - 8) with biomass of same variety , T7 : Brassica (BARI sarisha - 11) without biomass, T8 : Brassica (BARI sarisha - 11) with biomass of same variety, T9 : Brassica (BARI sarisha - 13) without biomass , T10 : Brassica (BARI sarisha - 13) biomass of same variety, T11 : Brassica (BARI sarisha - 15) without biomass, T12 : Brassica (BARI sarisha - 15) with biomass of same variety. Results revealed that T1 treatment (no Brassica + no biomass) resulted the highest weed population at 30 DAS (days after sowing) (230.80 m−2) and at 60 DAS (300.70 m−2). On the other hand T6 treatment (BARI Sarisha-8 + biomass) resulted the lowest weed population at 30 DAS (100.40 m−2) and at 60 DAS (181.30) m−2 which was statistically similar with other Brassica crop with biomass treated plots. The highest dry weight of weed in wheat field was observed in T1 treatment (no Brassica + no biomass) at 30 DAS and (29.14 g m−2) and 60 DAS (57.51 g m−2). At 30 DAS the lowest dry weight of weed (8.33 gm−2) in wheat field was observed in T6 treatment, while at 60 DAS the lowest weed dry weight (22.98 g m−2) recorded from T12 treatment, which was statistically similar with other Brassica biomass treated plots. The highest number of effective tiller (42.67 m−1) and highest grain yield was found from T12 treatment (1.75 t ha-1) whereas, the lowest number of effective tiller (32.67 m−1) and the lowest grain yield (1.36 t ha−1) was found from T1 treatment. It appeared from the above results that, weed population did not differ for varietal effect but varied for biomass irrespective of variety. Incorporation of Brassica biomass reduced 35% and 21% weed population in wheat field compared to that of T1 (no Brassica crop and no Brassica biomass). It was also observed that the T1 treatment resulted 19%, 20% and 21% lower wheat grain yield compared to T8, T6 and T12 respectively. So, the treatments containing Brassica crop with Brassica biomass of the same variety not only controlled weed in the wheat field but also encouraged yield contributing characters of wheat and gave higher grain yield than the treatments containing no Brassica and no Brassica biomass.