Banca de DEFESA: JOCILENE DOS SANTOS PEREIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: JOCILENE DOS SANTOS PEREIRA
DATA: 25/04/2025
HORA: 10:00
LOCAL: On line - meet.google.com/kdg-ohfv-pcd
TÍTULO:

GENETIC BREEDING AND MANAGEMENT FOR BIOTIC AND ABIOTIC STRESSES IN UPLAND RICE 

 

PALAVRAS-CHAVES:

Oryza sativa; drought stress; Cercospora janseana; fungicide.

PÁGINAS: 98
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitotecnia
ESPECIALIDADE: Melhoramento Vegetal
RESUMO:

Rice (Oryza sativa L.) is one of the most widely cultivated cereal crops in the world, representing a major food source for the global population. It can be grown under upland and flooded systems, both of which face challenges especially those related to environmental stressors that limit crop production. Among these, drought and the occurrence of diseases are particularly common. Therefore, this study aimed to investigate strategies for addressing both biotic and abiotic stresses in rice cultivation.Two distinct studies were conducted. The first focused on evaluating upland rice lines subjected to simulated drought stress under laboratory and greenhouse conditions, with the goal of selecting promising genotypes for drought tolerance in upland environments. The second project addressed biotic stress, specifically aiming to analyze the interaction between genetic resistance and fungicide application in the control of Cercospora in rice. The drought stress experiments were carried out at the Federal University of Lavras (UFLA), located in Lavras, Minas Gerais, Brazil. Upland rice lines were tested alongside reference checks for drought tolerance and sensitivity. In the laboratory, drought conditions were simulated using the PEG 6000 polymer, while field capacity measurements were taken in the greenhouse. Assessments were made at both seedling and full-cycle stages. Laboratory evaluations focused on root and shoot length, whereas agronomic, physiological, and biochemical traits were assessed in the greenhouse experiment. The biotic stress study was conducted at research stations of the University of Arkansas Division of Agriculture, in the state of Arkansas, USA. This part of the research focused on symptoms caused by Cercospora janseana. Three cultivars with contrasting resistance and susceptibility profiles were evaluated under different propiconazole application timings during the crop cycle. Disease symptoms and grain yield were recorded as response variables. All data were statistically analyzed using R software. The results demonstrated that both laboratory and greenhouse drought simulation methodologies were effective in identifying lines with superior performance and development, indicating a capacity for drought tolerance in upland rice. Selected lines exhibited traits such as deeper, more robust root systems and lower spikelet sterility. These findings allowed the identification of potential drought-tolerant genotypes for upland rice cultivation. Regarding C. janseana infection, symptoms were restricted to the plant tillers. Differences among cultivars were observed in terms of disease incidence and symptom expression. Propiconazole proved effective in reducing disease symptoms, which was associated with increased grain yield. Although further studies are needed, these findings offer valuable preliminary insights into narrow brown leaf spot—a reemerging and understudied disease in the U.S. In conclusion, the strategies explored in this thesis to manage biotic and abiotic stress in rice have shown significant potential for mitigating the negative impacts of these challenges on crop productivity.

MEMBROS DA BANCA:
Externo à Instituição - CAMILA PRIMIERI NICOLLI - UARK (Membro)
Externo à Instituição - JANINE MAGALHÃES GUEDES - EPAMIG (Suplente)
Externo à Instituição - WILSON VICENTE SOUZA PEREIRA - UFPI (Membro)
Externo ao Programa - HELOISA OLIVEIRA DOS SANTOS - DAG/ESAL (Membro)
Interno - EVANDRO NOVAES (Suplente)
Interno - WELISON ANDRADE PEREIRA (Membro)
Presidente - FLAVIA BARBOSA SILVA BOTELHO (Membro)