Sugarcane tolerance to ratoon eradication with glyphosate determined by physiological responses

Abstract

-This study aimed to evaluate the tolerance of sugarcane cultivars to ratoon eradication under different glyphosate rates by means of physiological responses. Therefore, a trial was carried out in randomized complete blocks with 4 x 4 factorial design (cultivars x rates) totaling 16 treatments with four replicates. The cultivars IAC91-5155, IACSP93-3046, and IAC86-2480 and IAC87-3396 and the glyphosate rates 0 g ha were tested. The variables analyzed were percentage of tiller mortality, quantum efficiency of PSII (Fv/Fm) and SPAD index. The results showed that there are differences among sugarcane cultivars for tiller eradication and for physiological responses with glyphosate different rates. The rate of 2,880 g hawas the most efficient in eliminating sugarcane tillers. The cultivars IAC86-2480, IAC87-3396 and IACSP93-3046 were the most sensitive and the IAC91-5155 tolerated, for a longer period of time, the damage to the photosynthetic apparatus of the ratoons caused by glyphosate desiccation. Due to different responses, different managements should be considered for eliminating ratoons of different cultivars.Keywords: Saccharum spp., varieties, tillers, chlorophyll fluorescence, SPAD, herbicide. IAC91-5155, IACSP93-3046, IAC86-2480 RESUMO -O presente trabalho teve como objetivo avaliar a tolerância de cultivares de cana-deaçúcar à erradicação de soqueiras com diferentes doses de glyphosate por meio de respostas fisiológicas. Para isso, um ensaio foi desenvolvido no delineamento experimental de blocos ao acaso em esquema fatorial 4 x 4 (cultivares x doses), totalizando 16 tratamentos com quatro repetições. Foram utilizados os cultivares

Photochemical, Anatomical, and Growth Changes in Cassava Cultivars after Application of Post-Emergent Herbicides

“…The photosynthetic apparatus of both Campinas and Sergipana cultivars was more affected by the herbicides fomesafen and fenoxaprop-p-ethyl; in contrast, lower damage was observed for the quantum efficiency of the PSII of the Campinas cultivar, which requires a longer period of time to present Fv/Fm damage and is less intense (Figure 1G,H). Significant changes in the Fv/Fm rates after application of N-(phosphonomethyl)glycine in the Saccharum officinarum crop were also observed by Silva et al [31], which showed reductions in the maximum efficiency of the photosystem.…”