Reaction of Rice Varieties to the Phytotoxicity of a New Herbicide, Roundup

Abstract

The reaction of a japonica-type rice variety, Chianung 242, and an indica-type rice variety, IR 8, to the toxicity of a new herbicide, Roundup, was evaluated at the Chiayi Agricultural Experiment Station in September of 1967. Roundup exceeded the active rate of 2.0 kg per ha was highly toxic to rice plant. The phytotoxicity of rice plant was lighter when Roundup was applied at 3 days instead of 10 days after transplanting. Japonica rice variety, Chianung 242 appeared to be more tolerant to the toxicity of Rundup than indica variety, IR 8.

本試驗以測定不同型水稻品種對新殺草劑Roundup藥害之反應為目的。供試材料為日本型品種，嘉農242號，印度型品種，IR8等兩品種。Roundup由Ramrod（CP 31393）7.5%與2.4-D2.5%混合製成為有效成分10%之粒劑，是美國Monsanto公司為在臺灣試驗而特別製成之產品。其施用量分為對照，每公頃有效藥量0.5，1.0，2.0及4.0公斤，分別於挿秧後3日及10日撒施於盆栽水稻，並按各處理藥害之輕重分級計分。由此調查結果得知，Roundup對供試水稻品種均具藥害，惟日本型品種，嘉農242號呈現藥害之程度似較印度型品種，IR8者輕微。Roundup施用量若超過每公頃有效成分2.0公斤以上時，就能引起供試水稻品種嚴重之藥害，惟挿秧後3日施用者似較挿秧後10日施用者為輕。