Banca de QUALIFICAÇÃO: IGOR NUNES BARCELLOS DA COSTA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : IGOR NUNES BARCELLOS DA COSTA
DATE: 03/07/2025
TIME: 14:00
LOCAL: Online
TITLE:

Characterization of NTSR resistance in Conyza sumatrensis under different temperatures

KEY WORDS:

Conyza, Conjugation, Vacuolar sequestration, Herbicide metabolism.

PAGES: 27
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Matologia
SUMMARY:

Weeds are highly detrimental to agricultural crops, causing considerable productivity losses and resulting in damage to production systems. One of the most harmful species is Conyza sumatrensis, known as horseweed, which stands out due to its high reproductive capacity, producing up to 60,000 seeds per cycle. In addition, the emergence of herbicide-resistant plants makes the management of these species even more difficult; currently, there are 21 reported cases of Conyza sumatrensis resistance worldwide. The aim of this research is to evaluate the metabolism of the herbicides 2,4-D and diquat and the influence of temperature on this process, as well as to assess whether different temperatures impact vacuolar sequestration and the resistance mechanism to glyphosate. The experiments will be conducted at UFRRJ, in the experimental area of the Weed and Pesticides in the Environment Research Group (PDPA). F3 generation seeds of horseweed, confirmed to be resistant to paraquat, diquat, saflufenacil, diuron, 2,4-D, and glyphosate, will be used. The seeds will be germinated in a growth chamber at a controlled temperature of 19°C in germination trays and then transplanted into 0.2 L plastic cups containing only substrate. Later, the seedlings will be transplanted into 1 L pots containing a mixture of 50% clay soil and 50% substrate. Three separate experiments will be conducted for the herbicides diquat, 2,4-D, and glyphosate. All will follow a 2x2 factorial design, with factor A being the two biotypes of Conyza sumatrensis (susceptible and herbicide-resistant) and factor B being the cultivation temperature conditions: cold (15°C) and warm (25°C). The experimental design will be completely randomized with four replications. Quantification of the enzymes catalase, superoxide dismutase, ascorbate peroxidase, glutathione-S-transferase, and glutathione reductase will be performed for the herbicides 2,4-D and diquat. For glyphosate, the activity of the enzymes carboxypeptidase and γ-glutamyl transpeptidase will also be assessed. All data will be subjected to a normality test (Shapiro-Wilk) and analysis of variance (ANOVA, p≤0.05), and if significant, mean comparisons will be conducted using Tukey’s test (p≤0.05). This study is expected to identify whether the resistance of Conyza sumatrensis to the herbicides 2,4-D, diquat, and glyphosate is of the NTSR (Non-Target-Site Resistance) type and how temperature influences this expression.

COMMITTEE MEMBERS:
Interna - 2466219 - CAMILA FERREIRA DE PINHO
Interno - 2181674 - LEONARDO OLIVEIRA MEDICI
Externo à Instituição - JUNIOR BORELLA - FURG