Banca de QUALIFICAÇÃO: MARIA TEREZA DE ALBUQUERQUE E NASCIMENTO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : MARIA TEREZA DE ALBUQUERQUE E NASCIMENTO
DATA : 20/12/2024
HORA: 14:00
LOCAL: Sala 02 - PPGFITO
TÍTULO:

Título 1: Postharvest rot of watermelons caused by Fusarium species

Título 2: Alternatives to conventional fungicide for the control of watermelon fruit rot

PALAVRAS-CHAVES:

Palavras-chave 1: Citrullus lanatus, fruit rot, molecular phylogeny

Palavras-chave 2: Citrullus lanatus, alternative treatment, salts, essential oils

PÁGINAS: 75
RESUMO:

 

Watermelon (Citrullus lanatus), it’s an important fruit in Brazil, producing 1.9 million ton/year, occupies the fifth place in the world, but post-harvest diseases are a major limitation, leading to losses of up to 15%. In 2022, 65 fresh and healthy watermelons cv. Harmonium (BASF^®) were collected from fields of Rio Grande do Norte and Ceará state, Brazil. After one week in a humid chamber, 51% showed lesions and mycelial growth, mainly in the peduncular area. Subsequently, small pieces (5 × 5 mm) of diseased tissues were placed on potato dextrose agar (PDA) and incubated at 25 ± 1 °C for 7 days. 16 single-spores isolates were obtained, which presented abundant colonies of aerial mycelium, with coloration ranging from white to dark orange. Based on these morphological features, the isolates were identified as Fusarium spp. The isolates were sent for further molecular analysis and two species were identified. F. falciforme to FSSC complex and F. pernambucanum belonging to FIESC complex. Koch's postulates were assessed on healthy watermelons cv. Harmonium and the reisolation confirmed were identical to the original isolates, fulfilling the postulates. To our knowledge, this is the first report of species of FSSC and FIESC complex causing postharvest rot in watermelons in Brazil and this information is important for the management of strategies to control the disease.

 

Watermelon fruit rot is one of the major causes of postharvest losses during their supply chain. The use of synthetic fungicides is increasingly questioned due to consumer concerns, increasing the challenging for alternative, safe, effective and sustainable methods to control pathogens both during watermelon cultivation and post-harvest. Two experiments were carried out to manage the disease, the first in vitro and the second in vivo. For the in vitro tests, the mycelial growth of F. falciforme, the most present and aggressive found in previous tests, was measured in nine different products and 5 doses each (1 to 5% or mg.L^-1), all of them included in the GRAS (Generally Recognized As Safe) list, including: Potassium Iodate (PI), Potassium Sorbate (PS), Sodium Benzoate (SB), Iodine (Io), Sodium Bicarbonate (SBC), Essential Oils of Fennel (EO Fe), Lemongrass (EO Lg) and Palmarosa (EO Pr), comparing the results with the synthetic post-harvest chemical registered for the crop in Brazil, Graduate A+^® (Azoxytrobin + Fludioxonil) and control (PDA only). For the in vivo test, the five products with the best responses from the previous test were used: PS, SB, OE Fe, OE Lg and OE Pr in 5 doses (1 to 5%) plus a negative treatment (Graduate - 1 to 5 mg.L ^-1) and a positive treatment (distilled water) on fruits of cv. Ana^® (Origene Seeds). After harvesting, the fruits were treated in the peduncular region and stored in a cold room (10 ± 1.5 °C) for 23 days. Graduate A+^® showed 100% control at all doses tested. SB and EO Pr achieved 90% control from 4%, while PS, EO Lg and EO Fe achieved 90% at 5% doses. However, essential oils caused damage to fruit tissues at concentrations ≥ 3%. SB and PS stood out as promising alternatives for managing stem rot in watermelons, especially at higher doses.

MEMBROS DA BANCA:
Externa à Instituição - CYNTHIA PATRICIA DE SOUSA SANTOS ALVES
Externa à Instituição - KAMILA CÂMARA CORREIA
Interna - 1544411 - MARCIA MICHELLE DE QUEIROZ AMBROSIO
Presidente - 1445570 - RUI SALES JUNIOR