Mayra Juline Gonçalves

Effect of four training systems on the temporal dynamics of downy mildew in two grapevine cultivars in southern Brazil

The aim of this study was to evaluate the temporal dynamics of downy mildew epidemics under four training systems: vertical shoot positioning (VSP), Geneva Double Curtain (GDC), Simple Curtain (SC) and Tendone in two cultivars (‘Cabernet Sauvignon’ and ‘Merlot’). Experiments were conducted at commercial vineyards in southern Brazil, during the 2012–2013 and 2013–2014 growing seasons. Downy mildew incidence and severity were quantified on a weekly basis from the first symptoms appearance until harvest. Training systems and cultivars were compared based on the following variables of downy mildew progress curves: a) beginning of symptoms appearance (BSA); b) maximum disease incidence and severity (Imax, Smax); c) time to reach maximum disease incidence/severity (TRMDI and TRMDS); and d) area under incidence and severity disease progress curve (AUIDPC and AUSDPC). The training systems significantly affected AUSDPC and Smax. AUSDPC was lowest in the VSP system in all cultivars and growing seasons. In addition, ‘Merlot’ showed significantly lower AUIDPC and AUSDPC than ‘Cabernet Sauvignon’ in both growing seasons. The Tendone and GDC systems showed significantly higher AUSDPC in all cultivars and growing seasons. Our results suggested that the use of the VSP system contributes to reduce downy mildew severity on ‘Merlot’ and ‘Cabernet Sauvignon’ in southern Brazil.

Protocolo para micropropagação de marmeleiro BA29 em meio semissólido

Micropropagation is a technique widely known for its ability to produce large numbers of plants in a short period of time. It is essential for breeding programs and to establish micropropagation protocols for economically important species. The aim of this study was to establish a micropropagation protocol for quince BA29, aiming at mass production of plantlets. The explants of quince BA29 were cultured on MS and WPM media (original and 1/2) in combination with BAP (0, 0.5, 1, 2 and 4 mg L-1) for the in vitro multiplication and cultured in MS medium with sucrose (15 and 30 mg.L-1) combined with IBA (0, 0.12, 0.25, 0.50, 1.0 and 2.0 mg L-1) for in vitro rooting. After 45 days, the culture media which provided the best results for growth and multiplication of BA29 explants was the MS original with 2.68 mg L-1 of BAP and the culture media which provided the best results for rooting of BA29 explants was MS with 15 g L-1 of sucrose and 1.25 mg L-1 of IBA.

Distribution and phylogenetics of whiteflies and their endosymbiont relationships after the Mediterranean species invasion in Brazil

The Bemisia tabaci is a polyphagous insect and a successful vector of plant viruses. B. tabaci is a species complex and in Brazil native species from the New World (NW) group, as well as the invasive species, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) were reported. For better understanding the distribution of the different species four years after the Mediterranean species invasion in Brazil, whiteflies were collected from 237 locations throughout the country between the years of 2013 and 2017, species were identified and the facultative endosymbionts detected. The survey revealed that MEAM1 was the prevalent species found on major crops across Brazil. It is the only species present in North, Northwestern and Central Brazil and was associated with virus-infected plants. MED was found in five States from Southeast to South regions, infesting mainly ornamental plants and was not associated with virus-infected plants. The prevalent endosymbionts identified in MEAM1 were Hamiltonella and Rickettsia; and the mtCOI analysis revealed low genetic diversity for MEAM1. In contrast, several different endosymbionts were identified in MED including Hamiltonella, Rickettsia, Wolbachia and Arsenophonus; and two distinct genetic groups were found based on the mtCOI analysis. Monitoring the distribution of the whiteflies species in Brazil is essential for proper management of this pest.

Relationship among Entomosporium severity, defoliation, and vegetative-reproductive variables in pear in Brazil

The objective of this work was to evaluate the relationship among Entomosporium severity, defoliation, and vegetative-reproductive variables of three European pear cultivars in Southern Brazil. The Packham’s Triumph, Abate Fetel, and Williams pear cultivars were assessed regarding Entomosporium severity, defoliation, and natural leaf fall every two weeks, from the appearance of the first symptoms at the beginning of January until the end of April, during the 2012/2013 and 2013/2014 crop seasons. The vegetative and reproductive variables were evaluated in July, during the dormant period. Data on Entomosporium severity were integrated over time and converted into the area under the disease progress curve (AUDPC). The coefficient of determination (R2) of the linear regression of Entomosporium severity versus defoliation was significant for all studied cultivars and crop seasons. Defoliation in trees affected by Entomosporium was significantly higher than natural leaf fall in the control trees protected by fungicides. A negative correlation was observed among defoliation, branch fertility index, and plant height, indicating that the higher the defoliation, the lower the development of the vegetative and reproductive variables plant height and vigor. Entomosporium severity differed significantly among cultivars when the AUDPC was considered the differentiating epidemiological variable. The Abate Fetel and Williams pear cultivars are the most susceptible and resistant to Entomosporium, respectively.

Basidiomycetes biodiversity founded in a fragment of Araucaria Forest

No que se refere a biodiversidade fungica do Parana, o estado e considerado entre os mais estudados, onde mais de 1.700 especies sao conhecidas, no entanto nao ha relatos da micota da regiao sudoeste do estado. Este trabalho teve como objetivo, coletar e identificar a biodiversidade de fungos macroscopicos em um fragmento de floresta ombrofila mista. As coletas foram realizadas mensalmente, de agosto de 2009 a outubro de 2010, abrangendo todos os periodos climaticos. Os basidiomas foram coletados ao longo da area, abrangendo plato, vertente e baixio. O procedimento de coleta foi realizado seguindo a metodologia adotada por Souza (1980). Apos a coleta, os fungos foram fotografados, coletados com auxilio de canivetes, depositados em sacos individuais de papel ou recipientes plasticos, sendo identificados quanto ao habitat e o substrato. Foram encontrados dezenove generos pertencentes a treze familias de Ganodermataceae, Polyporaceae, Coprinaceae, Strophariaceae, Phuteaceae, Bolbitaceae, Agaricaceae, Maramiaceae, Suillaceae, Tricholomataceae, Ramariaceae, Auriculariaceae, Sclerodermataceae. Dentre estes generos, tres no solo, um encontrado na grama, quinze generos encontrados em tronco de arvores (saprofitas), Amauroderma, Auricularia, Coprinus, Laccaria, Leucoagaricus, Leucocoprinus, Microporellus, Mycena, Panaculos, Phuteos, Polyporus,