Qualidade de sementes de plantas de soja infectadas com Macrophomina phaseolina (Tassi) Goid. em estádios fenológicos reprodutivos
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Data
2020-08-28
Autores
Sanches, Ana Clara Nobre
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Universidade Estadual Paulista (Unesp)
Resumo
Macrophomina phaseolina infecta diversas espécies, entre elas a soja, produz microescleródios capazes de permanecer viáveis no solo por longos períodos, dificultando o controle desse patógeno após sua introdução na área. O fungo pode ser introduzido em novas áreas a partir de sementes obtidas de plantas infectadas, promovendo a invibialização de sementes e de plântulas, ou originando novas plantas infectadas. Deste modo, a produção das sementes de soja deve atender aos padrões de sanidade para garantir a qualidade das sementes produzidas. Para evitar a disseminação da doença na lavoura destinada à produção de sementes, é imprescindível realizar o manejo adequado ao estágio da planta evitando perdas de qualidade das sementes. Diante do exposto, a pesquisa realizada teve o objetivo de avaliar o efeito da infecção de M. phaseolina em plantas de soja em estádios reprodutivos para mensurar o impacto do patógeno nos componentes de produção, qualidade fisiológica e sanitária das sementes produzidas. O experimento foi realizado em três cultivares de soja (BMX-Potência, BS 2606 IPRO, M5947 IPRO), em casa de vegetação, entre novembro de 2018 a março de 2019. As plantas foram inoculadas nos estádios R5, R6 e R7 com discos de BDA colonizados com micélio de M. phaseolina presos à haste. Constatada a infecção, ao atingir o estádio R9, as sementes foram colhidas manualmente e avaliadas em laboratório. A sanidade foi avaliada pelo método de papel filtro. Para avaliar a qualidade fisiológica foram realizados os testes de germinação, vigor (primeira contagem de germinação - PCG, T50, crescimento de raiz e parte aérea) e foi avaliado o teor de água. As cultivares responderam de maneira diferente ao período da inoculação. Para a cultivar BMX-Potência, a inoculação não interferiu na produtividade, germinação, PCG, T50 e comprimento na raiz. Para essa cultivar, verificou-se menor comprimento da parte aérea quando as plantas foram inoculadas no estágio R7. Para a cultivar BS 2606 IPRO, não houve interferência na germinação e PCG, sendo os piores resultados de T50 e comprimentos de raiz e parte aérea obtidos com a inoculação em R7, sem diferir de R6. A menor produção para esta cultivar foi observada com a inoculação em R6, sem diferir de R7. Na cultivar M5947 IPRO, a inoculação em R6 resultou em menor porcentagem de germinação, seguida de R7. A inoculação não interferiu na produção e no vigor (PCG e T50) dessa cultivar, mas resultou menor comprimento de planta com a inoculação em R7, sendo que os estádios de inoculação não diferiram entre si. Quanto à sanidade das sementes, a inoculação em R6 resultou em maior incidência de M. phaseolina, seguida de R7. Os resultados evidenciam que a infecção de M. phaseolina nos estádios R6 e R7 compromete, em maior dimensão, a qualidade das sementes de soja produzidas.
Macrophomina phaseolina infects many species, including soybean, and produces microesclerotia capable of remaining viable in soil for long periods, making it difficult to control this pathogen after its introduction in an area. The fungus can be introduced in new areas through seeds obtained from infected plants, promoting seeds and seedlings death, or originating new infected plants. This way, soybean seeds production must follow sanitary standards in the fields to assure seed sanitary quality. To avoid dissemination of the disease in the seed production fields, it is essential to manage it according to the plant stages avoiding seed quality losses. Therefore, this research aimed at evaluating the effect of M. phaseolina infection in soybean plants in reproductive stages to measure the impact of the pathogen on production components, as well as physiological and sanitary quality of the produced seeds. The experiment was performed with three soybean cultivars (BMX-Potência, BS 2606 IPRO, M5947 IPRO), in greenhouse, between November/2018 and March/2019. The plants were sowed in autoclaved soil and inoculated with PDA disk containing M. phaseolina mycelium, attached to the stem in R5, R6 and R7 stages. After the infectionwas confirmed, as it reached the R9 stage, the seeds were manually harvested and evaluated in the lab. The sanitary quality was evaluated with blotter test method. To evaluate physiological quality, germination, vigor (first count of germination - FCG, T50, root and stem growth) and water content tests were performed. The cultivars had different reaction to the inoculation. Regarding BMX-Potência, the inoculation did not interfere with productivity, germination, FCG, T50 and root growth. Smaller stem growth was verified when the plants were inoculated in R7. Concerning cultivar BS 2606 IPRO, there was no interreference in germination nor FCG. The worst T50 and root and stem growth were observed in inoculation in R7, which did not differ from R6. The lowest yield to this cultivar was observed in R6, without differing from R7. In cultivar M5947 IPRO, the inoculation in R6 resulted in the lowest germination, followed by R7. The inoculation did not interfere with production and vigor (FCG and T50) of this cultivar, but resulted in smaller height in R7 inoculation, the inoculated stages did not differ. Regarding seed sanitary quality, inoculation in R6 resulted in higher incidence of M. phaseolina, followed by R7. The results highlight that M. phaseolina infection in stages R6 and R7 severely compromisethe quality of soybean seeds produced.
Macrophomina phaseolina infects many species, including soybean, and produces microesclerotia capable of remaining viable in soil for long periods, making it difficult to control this pathogen after its introduction in an area. The fungus can be introduced in new areas through seeds obtained from infected plants, promoting seeds and seedlings death, or originating new infected plants. This way, soybean seeds production must follow sanitary standards in the fields to assure seed sanitary quality. To avoid dissemination of the disease in the seed production fields, it is essential to manage it according to the plant stages avoiding seed quality losses. Therefore, this research aimed at evaluating the effect of M. phaseolina infection in soybean plants in reproductive stages to measure the impact of the pathogen on production components, as well as physiological and sanitary quality of the produced seeds. The experiment was performed with three soybean cultivars (BMX-Potência, BS 2606 IPRO, M5947 IPRO), in greenhouse, between November/2018 and March/2019. The plants were sowed in autoclaved soil and inoculated with PDA disk containing M. phaseolina mycelium, attached to the stem in R5, R6 and R7 stages. After the infectionwas confirmed, as it reached the R9 stage, the seeds were manually harvested and evaluated in the lab. The sanitary quality was evaluated with blotter test method. To evaluate physiological quality, germination, vigor (first count of germination - FCG, T50, root and stem growth) and water content tests were performed. The cultivars had different reaction to the inoculation. Regarding BMX-Potência, the inoculation did not interfere with productivity, germination, FCG, T50 and root growth. Smaller stem growth was verified when the plants were inoculated in R7. Concerning cultivar BS 2606 IPRO, there was no interreference in germination nor FCG. The worst T50 and root and stem growth were observed in inoculation in R7, which did not differ from R6. The lowest yield to this cultivar was observed in R6, without differing from R7. In cultivar M5947 IPRO, the inoculation in R6 resulted in the lowest germination, followed by R7. The inoculation did not interfere with production and vigor (FCG and T50) of this cultivar, but resulted in smaller height in R7 inoculation, the inoculated stages did not differ. Regarding seed sanitary quality, inoculation in R6 resulted in higher incidence of M. phaseolina, followed by R7. The results highlight that M. phaseolina infection in stages R6 and R7 severely compromisethe quality of soybean seeds produced.
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Palavras-chave
Macrophomina phaseolina, Soja, Sanidade de sementes, Germinação, Vigor de sementes, Seed sanitary quality, Germination, Seeds, Soybean