The Feasibility Study of Utilizing Common Herbicides of Transplanted Rice for Direct Wet-Seeding of Hashemi Cultivar

To investigate some common herbicides of transplanted rice for direct wet-seeding of Hashemi cultivar, this study was conducted in a randomized complete block design with three replications. Treatments were as follow: (i) recommended dose of pretilachlor, (ii) oxadiargyl + bensulfuron-methyl, (iii-vi) adding propanil or thiobencarb to treatment (i) and (ii), (vii-x) adding cinosulfuron to treatment (iii) to (vi), (xi) weed free condition, and (xii) weed infested condition. The highest total weed infestations were observed when pretilachlor, oxadiargyl + bensulfuron-methyl and pretilachlor plus propanil or thiobencarb had been applied. The highest rice height was recorded in weed infested, but for other traits, comparison of herbicide treatments showed the least rice growth and yield for pretilachlor (due to the highest weed competition) and oxadiargyl + bensulfuron-methyl + thiobencarb. In the recent treatment panicle and grain number, and 1000-grain weight were lower than those for individual application of pretilachlor. Since applying oxadiargyl + bensulfuron-methyl suppressed weeds better than treatments containing pretilachlor, and also considering the effective control of nutsedge by bensulfuron-methyl, and barnyardgrass by thiobencarb, it seems that the phytotoxicity effects of oxadiargyl + bensulfuron-methyl + thiobencarb on rice are serious. In the herbicide applied treatments, the maximum number of tiller and panicle, and biological and grain yield were observed in oxadiargyl + Bensulfuron-methyl+ Propanile treatments. Despite the acceptable weed control, it seems that Hashemi cultivar was susceptible to herbicides in saturated soil condition and symptoms of phytotoxicity were appeared in crop plants.