Evaluation The Efficacy of New Herbicides to Control Weeds in Trade Inbred Lines of Corn (Zea mays L. SC704)

To control weed in SC704 corn inbred lines using new herbicides, an experiment was conducted in randomized complete block design with four replication and ten treatments in AgriculturalResearchCenter and Natural Resources of Khorasan Razavi Province, in Mashhad during 2010. The treatments consisted of Nicosulfuron (Cruz 4%SC, 80 g ha-1), Nicosulfuron + Bromoxynil + MCPA (Nicosclfuron 4% SC+ Bromicid MA® 4%EC, 80 + 400 g ha-1), Rimsulfuron + Nicosulfuron (Ultima® DF75%, 90 and 127.5 g ha-1), Foramsulfuron (Equip® 22.5% OD, 337.5 and 562.5 g ha-1), and Mesotrione + S-Metolachlor + Terbuthylazine (Lumax® 537.5 SE, 1344 and 1881 g ha-1). Two treatments weed free and weed infested were also included as checks. The most frequent weeds were Amaranthus retroflexus L., Portulaca oleracea L., Solanum nigrum L., and Chenopodium album L. The results showed that all herbicides could significantly reduce the density and dry weight of weeds. The most efficient treatment for the weed control was Nicosulfuron + Bromoxynil + MCPA with 76.7% and 80.9% reduction of weed density and weed dry weight, respectively. Further more Mesotrione + S-Metolachlor + Terbuthylazine (1344 g ha-1) was the most efficient in reducing weed density and weed dry weight. Combination of Rimsulfuron + Nicosulfuron (90 g ha-1) with 0.936 t ha-1 was the most inefficient treatment for hybrid seed yield.