Influência da vernalização negativa na concentração de potyvírus em alho-semente e levantamento, caracterização de orthotospovírus e identificação de espécimes de tripes na cultura da soja
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Data
2023-06-02
Autores
Uzan, Juliana [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A cultura do alho, sendo originária das zonas temperadas da Asia Central, necessita do processo de vernalização para sua diferenciação, quando plantada na região central do Brasil. A vernalização convencional consiste em submeter os bulbos em uma câmara fria por 5±1°C, durante 45 dias. Entretanto, uma nova técnica de vernalização, chamada de negativa, vem sendo empregada por alguns produtores de alho. Na vernalização negativa os bulbos são submetidos a temperaturas em torno de -2±1°C por 50 dias, antes do plantio. Os vírus, principalmente os potyvirus, são muito frequentes infectando alho e acarretam principalmente em redução de produtividade e qualidade dos bulbos. No Capitulo 1 desta tese foram realizados ensaios com a finalidade de avaliar o efeito da vernalização convencional e negativa sobre a concentração de potyvírus e a produtividade do alho. Bulbos sabidamente infectados por potyvírus foram submetidos a vernalização convencional e negativa e plantados em uma área comercial na região de Santa Juliana, MG. Observou-se redução da concentração de potyvírus aos 30 dias após o plantio em bulbilhos de alho submetidos à vernalização negativa. O peso médio dos bulbos foi estatisticamente maior no tratamento com vernalização negativa e estes apresentaram menos defeitos de má formação, conhecido como “macaquinho”, quando comparados aos bulbos submetidos à vernalização convencional, concluindo-se que a vernalização negativa apresenta efeitos benéficos ao desenvolvimento do alho. No Capitulo 2 foi avaliada a ocorrência de orthotospovirus em soja (Glycine max L. Merril) e as espécies de tripes mais comuns associadas a cultura no Estado de São Paulo. Isolados de Groundnut ringspot orthotospovirus (GRSV) provenientes de soja também foram avaliados quanto a gama de hospedeiros e capacidade de transmissão por sementes de soja. Os dados foram obtidos durante as safras 2020/2021 e 2021/2022. Os resultados mostraram a distribuição do GRSV em diversas áreas do estado de São Paulo, além da incidência de espécimes de tripes pertencentes às espécies Caliotriphis phaseoli, Frankliniella schultzei e Frankliniella occidentalis. Sequências parciais do genoma de orthotospovírus indicam a ocorrência somente da espécie Groundnut ringspot orthotospovirus em soja. Ensaios biológicos usando quatro isolados diferentes de GRSV da soja mostraram que alguns isolados são facilmente transmitidos para plantas de pimentão e fumo, enquanto outros não foram capazes de serem transmitidos por esta técnica. Foi verificada uma taxa de 0,2% de transmissão do GRSV por sementes de soja, indicando que sementes podem servir como inóculo primário do vírus no campo.
The garlic culture, being originally from the temperate zones of Central Asia, needs the vernalization process for its differentiation, when planted in the central region of Brazil. Conventional vernalization consists of placing the bulbs in a cold chamber at 5±1°C for 45 days. However, a new vernalization technique, called negative vernalization, has been used by some garlic producers. In the negative vernalization, bulbs are subjected to temperatures around -2±1°C for 50 days, before planting. Viruses, mainly potyviruses, are very frequently found infecting garlic and causes a reduction of productivity and quality of bulbs. In Chapter 1 we evaluate the effect of conventional and negative vernalization of garlic bulbs on potyvirus concentration and garlic yield. Bulbs, known to be infected by potyvirus, were subjected to conventional and negative vernalization and planted in a commercial area in the region of Santa Juliana, MG. There was a reduction in potyvirus concentration 30 days after planting in garlic bulbs submitted to negative vernalization. The average weight of the bulbs was statistically higher in the treatment with negative vernalization and they showed less malformation defects, known as "macaquinho" when compared to bulbs submitted to conventional vernalization. We conclude that negative vernalization has positive effects on garlic development. In Chapter 2, we evaluate the occurrence of orthotospovirus in soybean (Glycine max L. Merril) and the most common thrips species associated with the crop, in the State of São Paulo. The host range of groundnut ringspot orthotospovirus (GRSV) isolates collected from soybeans, and the soybean seed transmission, were evaluated. The data were obtained from 2020/2021 and 2021/2022 soybean season. GRSV was detected in several soybean groying areas of São Paulo State, in addition of thrips belonging to the species Caliotriphis phaseoli, Frankliniella shultzei and Frankliniella occidentalis. Partial sequences of the orthotospovirus genome indicate the GRSV occurrence in soybean. Biological assays with four different GRSV isolates from soybean showed that some isolates are easily transmitted to sweet pepper and tobacco plants, while others were not able to be transmitted by this technique. A rate of 0.2% of GRSV transmission by soybean seeds was verified, indicating that seeds can serve as a primary inoculum of the virus in the field.
The garlic culture, being originally from the temperate zones of Central Asia, needs the vernalization process for its differentiation, when planted in the central region of Brazil. Conventional vernalization consists of placing the bulbs in a cold chamber at 5±1°C for 45 days. However, a new vernalization technique, called negative vernalization, has been used by some garlic producers. In the negative vernalization, bulbs are subjected to temperatures around -2±1°C for 50 days, before planting. Viruses, mainly potyviruses, are very frequently found infecting garlic and causes a reduction of productivity and quality of bulbs. In Chapter 1 we evaluate the effect of conventional and negative vernalization of garlic bulbs on potyvirus concentration and garlic yield. Bulbs, known to be infected by potyvirus, were subjected to conventional and negative vernalization and planted in a commercial area in the region of Santa Juliana, MG. There was a reduction in potyvirus concentration 30 days after planting in garlic bulbs submitted to negative vernalization. The average weight of the bulbs was statistically higher in the treatment with negative vernalization and they showed less malformation defects, known as "macaquinho" when compared to bulbs submitted to conventional vernalization. We conclude that negative vernalization has positive effects on garlic development. In Chapter 2, we evaluate the occurrence of orthotospovirus in soybean (Glycine max L. Merril) and the most common thrips species associated with the crop, in the State of São Paulo. The host range of groundnut ringspot orthotospovirus (GRSV) isolates collected from soybeans, and the soybean seed transmission, were evaluated. The data were obtained from 2020/2021 and 2021/2022 soybean season. GRSV was detected in several soybean groying areas of São Paulo State, in addition of thrips belonging to the species Caliotriphis phaseoli, Frankliniella shultzei and Frankliniella occidentalis. Partial sequences of the orthotospovirus genome indicate the GRSV occurrence in soybean. Biological assays with four different GRSV isolates from soybean showed that some isolates are easily transmitted to sweet pepper and tobacco plants, while others were not able to be transmitted by this technique. A rate of 0.2% of GRSV transmission by soybean seeds was verified, indicating that seeds can serve as a primary inoculum of the virus in the field.
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Palavras-chave
Potyvirus, Allium sativum, Glycine max, Groundnut ringspot virus, Levantamento, Survey