Banca de DEFESA: CÍNTIA LUIZA BATALHA XAVIER

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : CÍNTIA LUIZA BATALHA XAVIER
DATA : 12/03/2020
HORA: 08:30
LOCAL: Sala 1 PPGF
TÍTULO:

Methodology for the Study of Clubroot in Vitro

PALAVRAS-CHAVES:

Plasmodiophora brassicae, cauliflower, nutritive solution, aluminum, root hair

PÁGINAS: 51
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitossanidade
ESPECIALIDADE: Fitopatologia
RESUMO:

Clubroot is one of the most limiting problems for the production of brassica in Brazil and in the world. It is caused by Plasmodiophora brassicae Wor., A phytopathogenic protozoan, inhabitant of the soil. Most of the information on the pathogen comes from temperate regions and few are the epidemiological studies on this disease in Brazil and other tropical regions. These soils, which are generally acidic and weathered, have high levels of exchangeable aluminum (Al ⁺⁺⁺) which negatively affects root development and accentuates the losses caused by the disease. The study of plant x pathogen x environment interaction, however, is difficult due to the biotophic nature of the pathogen and the complexity of its life cycle. Thus, the present work was designed with the objective of developing methodology for in vitro tests and investigating the effect of Al ⁺⁺⁺ in the process of infection and colonization of roots by the pathogen and development of cauliflower plants (Brassica oleraceae var. botrytis ). Four experiments were carried out with a randomized experimental design. The first one to evaluate tips as containers with 35 repetitions in a 4 x 1 factorial scheme, composed of the substrate factor with 4 levels (vermiculite, sand, vermiculite + sand and germitest paper) and the inoculation factor with one level with Plasmodiophora brassicae. In the second experiment there were 5 repetitions in a 2 x 2 x 3 factorial scheme composed of the substrate factor with two levels (vermiculite and germitest paper), the inoculation factor with 2 levels (control and inoculated) and the nutrient solution factor with 3 levels (pH 6.5, pH 5.0 and pH 5.0 + 30 µmol L^-1 Al). The third and fourth experiments had 4 repetitions and a 2 x 2 x 5 factorial scheme, where the substrate factor of the third was composed of two levels (vermiculite and germitest paper) and in the fourth by (sand and germitest paper), the factor inoculation with two levels (control and inoculated) and the nutrient solution factor with 5 levels (0, 20, 30, 40 and 60 µmol L^-1 Al). In all experiments, a cauliflower seed cv Juliana was sown by tip and they were inoculated with a spore suspension with a concentration of 10⁸ spores mL^-1. Then, the total fresh weight, fresh root weight and percentage of infected root hair were evaluated. The Winrhizo scanner was also used to analyze the physical characteristics of the roots and microphotographs of the roots were made. At the end of the tests, the data were tabulated and submitted to analysis of variance and the means compared by the Tukey test (p ≤ 0.005) using the Sisvar statistical program. The graphics were assembled using the Sigma-Plot program. It is concluded that the best substrates for the development of plants was vermiculite followed by vermiculite + sand, germitest paper and sand. For the visualization of root hair infection, the best substrate was the germitest paper. For the study of the interaction between plant development and the study of pathogen infection, the best substrate is the germitest paper. It was not possible in this study to observe a significant effect of the effect of aluminum on the development of roots and plants, and in the process of infection and colonization of roots of B. oleracea under greenhouse conditions.

MEMBROS DA BANCA:
Presidente - 1213072 - MARGARIDA GORETE FERREIRA DO CARMO
Externo ao Programa - 2213075 - EVERALDO ZONTA
Externo à Instituição - SILVALDO FELIPE DA SILVEIRA - UENF