Diversidade e sensibilidade de Cyperus ferax ao herbicida Penoxsulam

Abstract

421Diversidade e sensibilidade de Cyperus ferax ao herbicida penoxsulam 1 Recebido para publicação em 27.4.2010 e na forma revisada em 6.5.2011. -1 ), comparativamente à testemunha sem aplicação. Existe diferença entre acessos de C. ferax quanto à sensibilidade ao herbicida penoxsulam. Os biótipos de C. ferax oriundos de lavouras de arroz irrigado da Depressão Central apresentam, em geral, maior acúmulo de massa seca da parte aérea e área foliar. Os biótipos C. ferax ocorrentes em lavouras de arroz do Rio Grande do Sul podem ser divididos em dois grupos, segundo características morfológicas.Palavras-chave: controle químico, Cyperaceae, Oryza sativa, planta daninha.ABSTRACT -The species of the genus Cyperus, Cyperaceae family, are the major weeds in the rice producing regions of the state of Rio Grande do Sul (RS). The objective of this study was to evaluate the diversity of Cyperus ferax in these regions and the sensitivity levels of this species to the herbicide penoxsulam. Thus, an experiment was conducted under greenhouse conditions in the Faculdade de Agronomia Eliseu Maciel. The experimental design was completely randomized, with four replications. Each experimental unit (plot) was composed of vases with a capacity of 0.55 dm 3 of soil, with seven plants. Treatments were arranged in a factorial design.Factor A evaluated the places of collection (origin) of the seeds of C. ferax, a weed in RS irrigated rice fields; and factor B evaluated susceptibility to the herbicide penoxsulam (125 g ha -1 ), compared to a control without application. Differences were verified between the accessions of C. ferax regarding sensitivity to the herbicide penoxsulam. The biotypes from the irrigated rice fields at Depressão Central show, in general, higher shoot dry mass accumulation and leaf area. The C. ferax biotypes at the RS rice fields can be divided into two groups, according to their morphological characteristics.

Control ofEchinochloasp. in the Irrigated Rice Crop

“…The penoxsulam herbicide is characterized as being selective in rice, controlling various weed species [13] and residual effect in the soil, which prevents the emergence of weeds new flow before establishment of flood irrigation [14]. In this context, the aim of the research was to evaluate the control of barnyardgrass in the irrigated rice cv Qualimax 1, depending on the time of onset of flooding, application times, and doses of penoxsulam.…”