Banca de DEFESA: FERNANDO RAMOS DE SOUZA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : FERNANDO RAMOS DE SOUZA
DATE: 24/03/2022
TIME: 13:00
LOCAL: Vídeo conferência - meet.google.com/ksy-tbkq-msa
TITLE:

Herbicides applied pre-emergence induce different responses in soybean plants

KEY WORDS:

Burndown, Biological nitrogen fixation, Resistance management, Antioxidant Enzymes, Reactive Oxygen Species

PAGES: 126
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Matologia
SUMMARY:

The objective of the present work was to evaluate the responses of soybean plants subjected to herbicides applied pre-emergence at different times before sowing. Two trials were conducted, in 2019/2020 and in 2020/2021 in a greenhouse. The herbicides triclopyr (0.72 and 0.96 kg and ha-1), diuron + sulfentrazone (0.35 + 0.175 kg ha-1), imazethapyr + flumioxazine (0.12 + 0.06 kg ha-1) were used. 1), diclosulan (0.035 kg ha-1) and imazapique + imazapique (0.078 +0.026 kg ha-1) in a factorial scheme (5 x 5 + 1), with factor A being herbicides and factor B, five application times before soybean sowing (0, 3, 5, 7 and 10 DAS), with controls without herbicides. At time zero, soybean was sowed. Phytotoxicity, chlorophyll a fluorescence, SPAD index and photosynthetic pigment content were evaluated at 7, 14, and 28 days after emergence (DAE). At 10 days DAE, the accumulation of H2O2, TBARS, SOD, CAT, APX, GSH, and soluble foliar proteins were evaluated, and at 40 DAS, the number and dry mass of nodules, part area and roots and nodular occupancy rate. At the end of the cycle, the crop production components were evaluated. It was also evaluated the growth of the strains in media containing different concentrations of the herbicides. The data obtained were submitted to anova and Tukey's test for comparison between means at 5% probability. The herbicides caused phytotoxicity in soybean plants in all evaluations carried out, promoting variations in chlorophyll a fluorescence parameters. There was no impact on chlorophyll and carotenoid concentrations. In the experiment conducted in 2019/2020, triclopyr caused an increase in nodulation at zero DAS, while the mixture imazapique + imazapyr caused a reduction in nodulation and in the accumulation of shoot dry mass, effects that were not observed in plants grown in the 2020/21 harvest. . Triclopyr and the imazapique + imazapyr mixture cause a reduction in plant root growth. Higher H2O2 content was observed in plants sown three DAA of diuron + sulfentrazone. Higher TBARS content was observed in plants submitted to diuron + sulfentrazone and imazapique + imazapyr at the three DAS. No differences in GST concentration were observed. SOD, CAT and APX. It was concluded that the evaluated herbicides and application times did not cause oxidative stress in soybean plants. There were reductions in grain production. Triclopyr herbicides and imazapique + imazapyr mixture applied at intervals of up to 20 days before soybean sowing can negatively impact soybean nodulation parameters, affecting crop development.

BANKING MEMBERS:
Interno - 1905333 - AROLDO FERREIRA LOPES MACHADO
Interna - 2466219 - CAMILA FERREIRA DE PINHO
Interno - 387256 - JORGE JACOB NETO
Externa à Instituição - CLÁUDIA POZZI JANTALIA - EMBRAPA
Externo à Instituição - MARCO ANTÔNIO MOREIRA DE FREITAS - IFGO