Tolerância de genótipos de feijão ao herbicida sulfentrazone em condição de campo

Abstract

The Weeds are one of the main obstacles to achieving high levels of productivity and grain quality in bean crops. There are few herbicides registered for use in this cultivated species able to control weeds in pre-emergence. The study was conducted in the Experimental Area of the Universidade Tecnológica Federal do Paraná, campus Pato Branco, aiming to evaluate the tolerance of eight bean genotypes (Bico de Ouro, Moyashi, BRS Esteio, IAC Esperança, IAC Harmonia, IPR Tangará and IPR Uirapuru) to the herbicide sulfentrazone, an inhibitor of the enzyme protoporphyrinogen oxidase (Protox), applied in pre-emergence. The experiment was conducted in a randomized block design with subdivided plots, in which the eight different genotypes are placed in the plots, while in the subplots the treatments with and without sulfentrazone application (400g i.a. ha-1) were placed. The following determinations were performed during the cycle: (a) tolerance at 7, 14, 21 and 28 days after application (DAA); (b) stand and plant height at 7, 14, 21 and 28 DAA; (c) total chlorophyll at 14, 21 and 28 DAA; (d) leaf area index at 28 DAA; (e) dry mass of the aerial part (MSPA) at 28 DAA. At the time of harvest, the final stand (ESTF), final height (ALTF), stem diameter (DMC), number of branches per plant (NRP), number of pods per plant (NVP), mass of thousand grains (MMG), moisture (UMG) and grain yield (RG) of beans were determined. It was found, in the field experiment, that the genotypes Bico de Ouro and Moyashi of the bean genus Vigna spp. showed greater tolerance to the application of the herbicide compared to the other bean classes. The beans BRS Esteio and IPR Uirapuru of the black bean classes, were the least tolerant.