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- Campus Samambaia, Campus Colemar Natal e Silva, Campus Aparecida de Goiânia.
Submissões Recentes
Combining ability as a strategy for selecting common bean parents and populations resistant to white mold
(2018) Ferreira, Lenio Urzeda; Melo, Patrícia Guimarães Santos; Vieira, Rogério Faria; Lobo Junior, Murillo; Pereira, Helton Santos; Melo, Leonardo Cunha; Souza, Thiago Lívio Pessoa Oliveira de
Common bean parents and populations resistant to white mold (WM, caused by Sclerotinia sclerotiorum) were selected based on estimates of general combining ability (GCA) and specific combining ability (SCA) for WM severity in three field nurseries in Brazil. Twenty-seven populations were obtained by partial diallel crosses between parents from two groups: GI) three sources of partial resistance identified abroad and GII) nine Brazilian cultivars and elite lines. Populations were advanced in bulk up to the F6 generation. The overall mean of WM severity from combined analysis ranged from 2.83 to 5.03 (scale of 1 to 9 scores) in the F6 population. The score of the susceptible control BRS Requinte was 7.21. The GI parents K-59, in Oratórios, MG, and Viçosa, MG, and K-407 and PI204717, in Goianira, GO, contributed to increase resistance to WM. The most promising populations for obtaining elite lines resistant to WM were K-59/BRS Executivo, PI204717/BRS Campeiro, PI204717/Jalo Precoce, K-59/BRS Radiante, and K-407/BRS Cometa.
Relações entre testes com metabólitos e seleção de isolados de Trichoderma spp. antagônicos a Sclerotinia sclerotiorum
(2016-03) Louzada, Gisele Angélica de Souza; Barbosa, Hellen Nogueira; Carvalho, Daniel Diego Costa; Martins, Irene; Lobo Junior, Murillo; Mello, Sueli Corrêa Marques de
Fungi of the Trichoderma genus have a versatility of action, as they can act by direct and/or indirect mechanisms. In view of this, multivariate analysis has been used in order to summarize and identify correlations among different mechanisms of biological control. We aimed to evaluate the antagonism of 16 Trichoderma spp. isolates against Sclerotinia sclerotiorum and identify the variables that best explain the antagonistic activity of Trichoderma spp. isolates against the pathogen in vitro. For that, isolates were confronted with the pathogen in paired culture (PC) and had the effect of their metabolites on the pathogen growth evaluated in volatile (VM), thermolabile (TLM), and non-thermolabile metabolite (NTLM) assays. Isolate CEN654 allowed only 17.1, 9.5, and 0.3% of pathogen growth in relation to the control in the VM, TLM, and NTLM assays respectively, standing out from the other isolates in the principal component analysis (PCA). The PCA also suggested that the PC and TLM assays are more suitable for the in vitro selection of isolates with antagonistic activity against S. sclerotiorum than the VM and NTLM ones.
Potential worldwide distribution of Fusarium dry root rot in common beans based on the optimal environment for disease occurrence
(2017-11) Macedo, Renan; Macedo, Lilian Patrícia Sales; Yoshida, Fernanda; Abud, Lidianne Lemes Silva; Lobo Junior, Murillo
Root rots are a constraint for staple food crops and a long-lasting food security problem worldwide. In common beans, yield losses originating from root damage are frequently attributed to dry root rot, a disease caused by the Fusarium solani species complex. The aim of this study was to model the current potential distribution of common bean dry root rot on a global scale and to project changes based on future expectations of climate change. Our approach used a spatial proxy of the field disease occurrence, instead of solely the pathogen distribution. We modeled the pathogen environmental requirements in locations where in-situ inoculum density seems ideal for disease manifestation. A dataset of 2,311 soil samples from commercial farms assessed from 2002 to 2015 allowed us to evaluate the environmental conditions associated with the pathogen's optimum inoculum density for disease occurrence, using a lower threshold as a spatial proxy. We encompassed not only the optimal conditions for disease occurrence but also the optimal pathogen's density required for host infection. An intermediate inoculum density of the pathogen was the best disease proxy, suggesting density-dependent mechanisms on host infection. We found a strong convergence on the environmental requirements of both the host and the disease development in tropical areas, mostly in Brazil, Central America, and African countries. Precipitation and temperature variables were important for explaining the disease occurrence (from 17.63% to 43.84%). Climate change will probably move the disease toward cooler regions, which in Brazil are more representative of small-scale farming, although an overall shrink in total area (from 48% to 49% in 2050 and 26% to 41% in 2070) was also predicted. Understanding pathogen distribution and disease risks in an evolutionary context will therefore support breeding for resistance programs and strategies for dry root rot management in common beans.
Plasticidade dos estômatos em folhas de Ichthyothere terminalis (Spreng) Blake (Asteraceae) em diferentes estações do ano
(2020) Vieira Neto, Honório; Abdalla, Dayana Figueiredo; Moraes, Moemy Gomes de
Cerrado has a diverse flora that occurs in different physiognomies. One of the striking features of the biome is the occurrence of well-defined rainy and dry seasons. During drought, Cerrado plants are subject to water restrictions. Stomata, which are epidermal structures responsible for gas exchanges, are essential for maintaining the plant water status. Ichthyothere terminalis (Spreng.) Blake is an herbaceous Asteraceae widespread e in the open Cerrado physiognomies. The species has a thickened underground system, which contributes to the plant's persistence in the environment. At the end of the drought, the aerial organs resprout. The objective of this work was to evaluate the stomatal dimensions in leaves of Ichthyothere terminalis at different seasons. Collections were carried out in open Cerrado physiognomies in dry and rainy periods, in which the plants were in different phenological phases. The leaves were collected, preserved, and fixed following the usual methods for anatomical and histometric analysis. The epidermis was cleared, and measurements and counts were made under a light microscope. The leaves of Ichthyothere terminalis are amphistomatic, with higher stomatal density on the abaxial surface. The density of stomata on the abaxial surface was higher in the transition between dry and rainy seasons. The area of the stomatal pores was greater at the beginning of the drought on both epidermal surfaces. The species showed the ability to change the attributes of stomata in different seasons, and this can contribute to its occurrence in habitats subject to seasonal drought.
Órgãos subterrâneos de Espada de São Jorge são fontes promissoras de frutanos
(2019) Silveira, Amanda Batista; Soares, Khályta Willy da Silva; Aguiar, Jhenyfer Rodrigues; Abraão, Cinara Ferreira; Moraes, Moemy Gomes de
Snake plant is a widely cultivated ornamental plant belonging to the Asparagaceae family. The species in this family often have rhizomes as storage organs, and fructans as the main stored nonstructural carbohydrates. These compounds are sucrose-derived fructose polymers. Due to their various benefits, they are of great interest to the food and pharmaceutical industries. The objective of this work was to quantify the nonstructural carbohydrate contents and to verify the presence of fructans in snake plant rhizomes and roots. For this, the belowground organs of plants cultivated in a flower bed, but not irrigated, were collected. Water content and soluble carbohydrate content in both organs were evaluated. The rhizomes of the species had higher water content and soluble carbohydrate content than the roots. Qualitative analyzes of soluble carbohydrates by high performance anion exchange chromatography showed the presence of fructans in both organs, with a profile similar to that observed in onion bulb extracts. We conclude that the belowground organs of snake plant store fructans with diversified structures that correspond to the inulin neoseries and that especially the rhizomes of this species are promising source for obtaining fructans.