Varietal response of different treatments on growth and yield attributes of paddy

Field experiments were conducted in two varieties of transplanted paddy (cv. Radha 4 and Neemai) during the rainy season of 2004–2005 in Mahendranagar, Nepal to assess the effect of weed management practice in growth and grain yield. Four experiments were conducted in randomized block design with three replicates viz. un-weeded (T₀), weed-free (TT), manured plus twice hand-weeded after 25 and 50 days of transplanting (T₁) and chemical fertilizer plus butachlor application (T₂). The mean maximum plant heights in weed-free plots were 108.27 cm and 138.01 cm in Radha-4 and Neemai respectively. This height was more or less similar to twice hand-weeded plots and herbicide treated plots being 11.8% lowering in both the varieties, compared to weed-free plots. The maximum grain yield in Radha-4 and Neemai was in weed-free plots 55.5 and 47.8 qha⁻¹ compared to 32.9 and 32.7 qha⁻¹ in unweeded plots, grain loss being 40.7% and 31.7% because of weeds in Radha-4 and Neemai varieties, respectively. Compared to weed-free plots the grain yield was 1.5% lower in twice hand-weeded plots in both varieties and 3.9% and 4.1% in herbicide treated plots in Radha4 and Neemai. The trend of varietal response in both the varieties were; weed-free (TT) > manured plus twice hand-weeded after 25 and 50 days of transplanting (T₁) > chemical plus butachlor application (T₂) > un-weeded (T₀).