Teste de condutividade elétrica e presença de patógenos em sementes de soja
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Data
2007-05-21
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Universidade Estadual Paulista (Unesp)
Resumo
O uso de procedimentos adequados para avaliar o vigor de semente é fundamental dentro do programa de controle de qualidade. No caso do teste de condutividade elétrica (CE) tem-se constatado efeito do patógeno sobre os resultados do mesmo. Assim, o trabalho teve como objetivo estudar a interferência dos fungos Phomopsis sojae e Colletotrichum dematium var. truncata nos resultados do teste em semente de soja. O trabalho foi conduzido usando-se sementes produzidas na safra 2005/2006. Estas foram inoculadas artificialmente com os fungos P. sojae e C. dematium var. truncata, utilizando-se meio de cultura BDA (batata, ágar e dextrose) acrescido de manitol (-1,0 MPa), por período de incubação de 20 horas, à temperatura de 25º C. Determinou-se o diâmetro de colônias, o índice de crescimento micelial; o teor de água da semente; a incidência de microorganismos (antes e após a inoculação) pelo teste de sanidade; o potencial fisiológico da semente pelos testes de germinação e de vigor (índice de velocidade de emergência, de frio, envelhecimento acelerado e condutividade elétrica) e a emergência de plântulas em campo. Determinou-se também a composição química da solução de embebição lixiviados (K+, CA+, Mg+ e Na+) e das sementes (K+, CA+, Mg+, Na+, P, C e N). Para análise estatística utilizou-se o delineamento inteiramente casualizado em esquema fatorial 2 x 4, (duas peneiras - 5,5 e 6,5 x quatro tratamentos - semente pura, semente em meio de cultura sem o fungo (- 1,0 MPa), semente inoculada com o fungo P. sojae(-1,0 Mpa) e semente inoculada com o fungo C. dematium var. truncata (-1,0 MPa), para as peneiras 5,5 e 6,5 mm, com oito e seis repetições respectivamente. Para o crescimento de colônias...
The use of adequate procedures to evaluate seed vigor is a very important tool within an assurance program of seed quality. Regarding the electrical conductivity test (EC) it has been verified the effect of some seedborn pathogens on the EC results. This research work was carried out in order to study the influence of the presence of Phomopsis sojae and Colletotrichum dematium var. truncata fungi on the EC results. The work was running using seeds produced in the agricultural year 2005/2006. The seeds were inoculated artificially with the fungi using the BDA (potato, agar and dextrose) medium with manitol (-1.0 MPa), incubated during 20 hours at temperature of 25o C. The colony diameter, index of micelial growth; seed water content; ocurrence of seedborn pathogens (before and after incubation); physiological potential of seeds using germination and vigor (speed germination index, cold test, accelerated aging and electrical conductivity) tests and seedling emergence in field were determined. Also, the composition of the soaked seed solution leachates (K+, Ca2+, Mg2+, Na+) and the seed (K+, Ca2+, Mg2+, Na+, P, C and N) were determined. A completely design in factorial 2 x 4 (two seed size 5.5 and 6.5 mm x four seed treatments purity seeds, seeds incubated in BDA without fungi, seeds incubated in BDA with Phomopsis and seeds incubated in BDA with Colletotrichum) arrangement, with eigth (5.5 mm) and six (6.5 mm) replications was used. The infection of soybean seeds with Phomopsis resulted on physiological seed quality reduction, but it did not xiii happen when the seeds were inoculated with Colletotrichum. There is no effect of seed inoculation in function of seed size. Based on the results is can be concluded that the occurrence of Phomopsis sojae fungi can interfere on the electrical conductivity results, but the same did not happen for the Colletotrichum dematium var. truncata fungi.
The use of adequate procedures to evaluate seed vigor is a very important tool within an assurance program of seed quality. Regarding the electrical conductivity test (EC) it has been verified the effect of some seedborn pathogens on the EC results. This research work was carried out in order to study the influence of the presence of Phomopsis sojae and Colletotrichum dematium var. truncata fungi on the EC results. The work was running using seeds produced in the agricultural year 2005/2006. The seeds were inoculated artificially with the fungi using the BDA (potato, agar and dextrose) medium with manitol (-1.0 MPa), incubated during 20 hours at temperature of 25o C. The colony diameter, index of micelial growth; seed water content; ocurrence of seedborn pathogens (before and after incubation); physiological potential of seeds using germination and vigor (speed germination index, cold test, accelerated aging and electrical conductivity) tests and seedling emergence in field were determined. Also, the composition of the soaked seed solution leachates (K+, Ca2+, Mg2+, Na+) and the seed (K+, Ca2+, Mg2+, Na+, P, C and N) were determined. A completely design in factorial 2 x 4 (two seed size 5.5 and 6.5 mm x four seed treatments purity seeds, seeds incubated in BDA without fungi, seeds incubated in BDA with Phomopsis and seeds incubated in BDA with Colletotrichum) arrangement, with eigth (5.5 mm) and six (6.5 mm) replications was used. The infection of soybean seeds with Phomopsis resulted on physiological seed quality reduction, but it did not xiii happen when the seeds were inoculated with Colletotrichum. There is no effect of seed inoculation in function of seed size. Based on the results is can be concluded that the occurrence of Phomopsis sojae fungi can interfere on the electrical conductivity results, but the same did not happen for the Colletotrichum dematium var. truncata fungi.
Descrição
Palavras-chave
Glycine max, Physiological seed quality, Seed vigor, Seedborn pathogens, Soja - Semente, Condutividade elétrica, Colletotrichum dematium, Phomopsis sojae, Patógeno
Como citar
TASSI, Adriana Luiza Wain. Teste de condutividade elétrica e presença de patógenos em sementes de soja. 2007. xiii, 41 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2007.