JAYADEVA, H. M.GURURAJ, SAJJAN2017-06-162017-06-162010-07-10TH-9663http://krishikosh.egranth.ac.in/handle/1/5810020967The field experiment was conducted during Kharif season of 2009 at Agricultural Research Station, Kathalgere, Channagiri taluk, Davanagere district, Karnataka state to find out the efficiency of Triasulfuron for weed control and grain yield in transplanted rice. Among the herbicides, Almix @ 4 g a.i. ha-1 caused the higher phytotoxicity followed by Triasulfuron @ 24 g a.i. ha-1 and resulted in stunted growth of the rice plants. Triasulfuron @ 24 g a.i. ha-1, Triasulfuron @ 12 g a.i. ha-1 and hand weeding twice recorded significantly lower density and dry weight of weeds at all growth stages of the crop as compared to other treatments. Hand weeding twice was found very effective against weeds upto 60 DAT thereafter its effect was suppressed and Triasulfuron @ 24 g a.i. ha-1 has become more effective. Grain and straw yields were higher in Triasulfuron @ 12 g a.i. ha-1 (6494 and 6930 kg ha-1, respectively). It was followed by hand weeding twice (6479 and 6893 kg ha-1 grain and straw yield, respectively). Among weed control treatments, the lower yield of grain and straw was recorded by Pyrazosulfuron 10 WP @ 25 g a.i. ha-1 (5828 and 6206 kg ha-1, respectively). Weed control efficiency was higher in Triasulfuron @ 24 g a.i. ha-1 followed by Triasulfuron @ 12 g a.i. ha-1 (93.67 and 91.45 %). Hand weeding twice was found on par with these two treatments with the WCE of 88.56 per cent. The significantly lower seed yield of all three test crops as obtained in pyrazosulfuron @ 25 g a.i. ha-1 followed by almix @ 4 g a.i. ha-1 is mainly due to the residual effect of these herbicides which resulted in lower germination and lower dry matter accumulation. Triasulfuron @ 12 g a.i. ha-1 resulted in higher B:C ratio (1.90) which was followed by Triasulfuron @ 10 g a.i. ha-1 (1.89) and Triasulfuron @ 24 g a.i. ha-1 (1.86).ennullThesis