Banca de QUALIFICAÇÃO: LUCAS SILVA DA SILVEIRA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : LUCAS SILVA DA SILVEIRA
DATE: 10/07/2025
TIME: 13:00
LOCAL: Sala 04 do IA
TITLE:

Adaptive cost of resistance to ACCase- and EPSPS-inhibiting herbicides in goosegrass

KEY WORDS:

Eleusine indica, ACCase, glyphosate, growth analysis

PAGES: 22
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Matologia
SUMMARY:

Resistant biotypes of Eleusine indica may exhibit adaptive costs, such as physiological and developmental changes compared to susceptible plants. This study aims to evaluate the adaptive cost of E. indica biotypes resistant and susceptible to the herbicides glyphosate, clethodim, and haloxyfop. Four experiments (E1, E2, E3, E4) will be conducted in a greenhouse and laboratories of the Weed Plants and Pesticides in the Environment (PDPA/UFRRJ) group in Seropédica, RJ. In E1, a screening will be conducted with four treatments and four replications: an untreated control and commercial doses of glyphosate (1.4 L a.e. ha⁻¹), haloxyfop (0.23 L a.e. ha⁻¹), and clethodim (0.45 L a.e. ha⁻¹). Visual injury assessments will be performed at 7, 14, 21, 28, and 35 days after application (DAA) using a scale from 0% (no symptoms) to 100% (plant death). E2 will consist of a dose–response assay using six biotypes selected from E1, with 10 treatments (control, D/16, D/8, D/4, D/2, D, 2D, 4D, 8D, 16D, where D is the dose used in E1 for each herbicide) and four replications. Visual injury and aboveground dry mass (ADM) will be evaluated at 35 DAA to calculate resistance factors (R/S) based on 50% visual control and ADM reduction. In E3, DNA from susceptible and resistant populations of six biotypes from E2 will be extracted, amplified, and sequenced by PCR, analyzing two ~500 bp fragments of the CT domain of the ACCase enzyme and one ~300 bp fragment of EPSPS. E4 will assess growth and metabolic characteristics of six biotypes from E2. A 6×8 factorial design with four replications will be used: factor A will consist of six biotypes (five resistant and one susceptible), and factor B will include eight sampling times (10, 20, 30, 40, 50, 60, 70, 80 days after emergence). Absolute growth rate, relative leaf growth rate, leaf area ratio, net assimilation rate, CO₂ assimilation, and chlorophyll a fluorescence transient will be analyzed. The results are expected to demonstrate adaptive costs in resistant E. indica biotypes, with physiological and growth differences, contributing to the development of more effective herbicide resistance management strategies.

COMMITTEE MEMBERS:
Interna - 2466219 - CAMILA FERREIRA DE PINHO
Externo ao Programa - 1905333 - AROLDO FERREIRA LOPES MACHADO - UFRRJExterna à Instituição - GABRIELA DE SOUZA DA SILVA - UFRRJ