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Physiological potential of soybean seeds treated in the industry with and without the application of dry powder

Potencial fisiológico de sementes de soja tratadas industrialmente com e sem a aplicação de pó secante

Abstract:

In soybean crops, industrial seed treatment is widely adopted, and it has allowed the development of new technologies, such as the use of dry powders. This work aimed to evaluate the effect of the industrial treatment, with and without the additional application of dry powder, on the physiological potential of soybean seeds. The experimental design was completely randomized, in a 4×2 factorial scheme, with four replications. Four chemical treatments were evaluated: 1) control, 2) carbendazim + thiram + thiamethoxam, 3) carbendazim + thiram, 4) thiamethoxam. Each trial was divided into one group that was treated and the other that remained untreated with the dry powder. The cultivars BRS 360 RR and BRS 284 were used and analyzed separately. The physiological potential of the seeds was determined by the following assessments: germination, first germination count, seedling emergence in sand, seedling total length, shoot length, and root length. Soybean cultivars respond differently to seed chemical treatments, regarding the effects on physiological potential. Using the dry powder results in problems in seed germination speed in the cultivar BRS 284. In the cultivar BRS 360 RR, the use of dry powder associated with thiamethoxam treatment reduces the physiological potential of the seeds.

Index terms:
Glycine max (L.) Merrill.; fungicides; insecticides; germination; emergence of seedlings

Resumo:

Na cultura da soja, o tratamento industrial de sementes é amplamente realizado e tem propiciado o desenvolvimento de novas tecnologias, como a utilização de pó secante. O objetivo deste trabalho foi avaliar o efeito do tratamento industrial de sementes, com e sem a aplicação de pó secante, sobre o potencial fisiológico de sementes de soja. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 4x2, com quatro repetições, sendo avaliados quatro tratamentos químicos de sementes: 1) testemunha, 2) carbendazim + thiram + tiametoxam, 3) carbendazim + thiram, 4) tiametoxam; todos na ausência e na presença de pó secante. As cultivares utilizadas foram a BRS 360 RR e a BRS 284, que foram analisadas separadamente. O potencial fisiológico das sementes foi determinado por meio das seguintes avaliações: germinação, primeira contagem de germinação, emergência de plântulas em areia, e comprimentos total, da parte aérea e da raiz das plântulas. As cultivares de soja respondem de forma diferenciada aos tratamentos químicos de sementes, quanto aos efeitos no potencial fisiológico. O pó secante resulta em problemas na velocidade de germinação das sementes da cultivar BRS 284. Na cultivar BRS 360 RR, o uso de pó secante associado ao tratamento com tiametoxam reduz o potencial fisiológico das sementes.

Termos para indexação:
Glycine max (L.) Merrill.; fungicidas; inseticidas; germinação; emergência de plântulas

Introduction

Soybean is a prominent culture in Brazil and worldwide. Within the agrobusiness scope, it is one of the economic activities that has increased the most in the last decades. This can be attributed to several factors, such as the development of technologies that boosted productivity, and also made the cultivation in different regions possible (Sediyama et al., 2013SEDIYAMA, A.F.; CASTRO JUNIOR, L.G.; CALEGARIO, C.L.L.; SIQUEIRA, P.H.L. Análise da estrutura, conduta e desempenho da indústria processadora de soja no Brasil no periodo de 2003 a 2010. Revista de Economia e Sociologia Rural, v.51, n.01, p.161-182, 2013. http://www.scielo.br/scielo.php?pid=S0103-20032013000100009&script=sci_arttext&tlng=pt
http://www.scielo.br/scielo.php?pid=S010...
; Hirakuri and Lazzarotto, 2014HIRAKURI, M.H; LAZAROTTO, J.J. O agronegócio da soja nos contextos mundial e brasileiro. Londrina: Embrapa Soja , 2014. 70p. (Documentos 349). https://ainfo.cnptia.embrapa.br/digital/bitstream/item/104753/1/O-agronegocio-da-soja-nos-contextos-mundial-e-brasileiro.pdf
https://ainfo.cnptia.embrapa.br/digital/...
).

Among these technologies, seed treatment stands out as an important way of controlling pathogens transmitted by seeds, and of ensuring the establishment of adequate plant populations. This is particularly relevant when the edaphoclimatic conditions during sowing are not favorable to germination and emergence of seedlings (Mertz et al., 2009MERTZ, L.M.; HENNING, F.A.; ZIMMER, P.D. Bioprotetores e fungicidas químicos no tratamento de sementes de soja. Ciência Rural , v.39, n.1, p.13-18, 2009. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782009000100003
http://www.scielo.br/scielo.php?script=s...
; Balardin et al., 2011BALARDIN, R.S.; SILVA, F.D.L.; DEBONA, D.; CORTE, G.D.; FAVERA, D.D.; TORMEN, N.R. Tratamento de sementes com fungicidas e inseticidas como redutores dos efeitos do estresse hídrico em plantas de soja. Ciência Rural, v.41, n.7, p.1120-1126, 2011. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782011000700002&lng=pt&tlng=pt
http://www.scielo.br/scielo.php?script=s...
; Pereira et al., 2011PEREIRA, C.E.; OLIVEIRA, J.A.; GUIMARÃES, R.M.; VIEIRA, A.R.; EVANGELISTA, J.R.E.; OLIVEIRA, G.E. Tratamento fungicida e peliculização de sementes de soja submetidas ao armazenamento. Ciência e Agrotecnologia , v.35, n.1, p.158-164, 2011. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542011000100020&lng=pt&tlng=pt
http://www.scielo.br/scielo.php?script=s...
).

Traditionally, seed treatment used to be performed before sowing, with proper machines, either at the resale or at the farmer’s property. However, seed companies, especially those who deal with soybean and corn seeds, have been adopting the seed treatment in the industry (STI), in which seeds are treated on the processing line, before storage, or at the moment of delivery. This form of treatment associates equipment and techniques of great efficiency and precision, and it allows the use of new chemicals and formulations. Furthermore, it provides a greater protection to the operators, and reduces the contamination of the environment (França-Neto et al., 2015FRANÇA-NETO, J.B.; HENNING, A.A.; KRYZANOWSKI, F.C.; HENNING, F.A.; LORINI, I. Adoção do tratamento industrial de sementes de soja no Brasil, safra 2014/2015. Informativo Abrates, v.25, n.1, p.26-29, 2015. http://www.abrates.org.br/img/informations/644f0c7f-9b60-4872-ba90-78622c333dd0_IA%20v25%20n1.pdf
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).

The treatment of soybean seeds in the industry showed physiological and sanitary advantages (Ludwig et al., 2011LUDWIG, M.P.; LUCCA FILHO, O.A.; BAUDET, L.; DUTRA, L.M.C.; AVELAR, S.A.G.; CRIZEL, R.L. Qualidade de sementes de soja armazenadas após recobrimento com aminoácido, polímero, fungicida e inseticida. Revista Brasileira de Sementes, v.33, n.3, p.395-406, 2011. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-31222011000300002
http://www.scielo.br/scielo.php?script=s...
; Brzezinski et al., 2015BRZEZINSKI, C.R.; HENNING, A.A.; ABATI, J.; HENNING, F.A.; FRANÇA-NETO, J.B.; KRZYZANOWSKI, F.C.; ZUCARELI, C. Seeds treatment times in the establishment and yield performance of soybean crops. Journal of Seed Science, v.37, n.2, p.147-153, 2015. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2317-15372015000200147&lng=en&tlng=en
http://www.scielo.br/scielo.php?script=s...
; Conceição et al., 2016CONCEIÇÃO, G.M.; LÚCIO, A.D.; MERTZ-HENNING, L.M.; HENNING, F.A.; BECHE, M.; ANDRADE, F.F. Physiological and sanitary quality of soybean seeds under different chemical treatments during storage. Revista Brasileira de Engenharia Agrícola e Ambiental, v.20, n.11, p.1020-1024, 2016. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016001101020&lng=en&tlng=en
http://www.scielo.br/scielo.php?script=s...
; Ferreira et al., 2016FERREIRA, T.F.; OLIVEIRA, J.A.; CARVALHO, R.A.; RESENDE, L.S.; LOPES, C.G.M.; FERREIRA, V.F. Quality of soybean seeds treated with fungicides and insecticides before and after storage. Journal of Seed Science , v.38, n.4, p.278- 286, 2016. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2317-15372016000400278&lng=en&tlng=en
http://www.scielo.br/scielo.php?script=s...
). However, problems were also reported, mainly in lots of low vigor seeds that had been submitted to excessively high volumes of slurry, resulted from the use of technological packs provided by the companies (Brzezinski et al., 2017BRZEZINSKI, C.R.; ABATI, J.; HENNING, F.A.; HENNING, A.A.; FRANÇA-NETO, J.B.; KRZYZANOWSKI, F.C.; ZUCARELI, C. Spray volumes in the industrial treatment on the physiological quality of soybean seeds with different levels of vigor. Journal of Seed Science , v.39, n.2, p.174-181, 2017. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2317-15372017000200174
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). To solve this problem, companies have used dry powder in order to induce seeds to dry fast and evenly. Thus, it is necessary to study the effects of the dry powder and its interaction with the chemical treatments on the physiological quality of the seeds.

On account of that, the objective of the present work was to assess the effect of the seed treatment in the industry, with and without the application of dry powder, on the physiological potential of soybean seeds.

Material and Methods

The experiment was conducted in the Laboratory of Physiology and Technology of Seeds, at the Technological Center of Seeds and Grains of Empresa Brasileira de Pesquisa Agropecuária, Embrapa Soja, located in the city of Londrina, state of Paraná (PR). The cultivars BRS 360 RR and BRS 284 were used, and they presented similar physiological quality prior to the treatments, with germination values of 96% and 93%, respectively, and moisture content of 11.5%, in both cultivars.

The experimental design was completely randomized, in a 4x2 factorial scheme, with four replications. The factors were composed by four seed chemical treatments: T1) control (no chemical treatment); T2) fungicide carbendazim + thiram (Derosal Plus®) + insecticide thiamethoxam (Cruiser®), dose 200 + 200 mL. 100 kg-1 seeds; T3) carbendazim + thiram (Derosal Plus®), dose 200 mL. 100 kg-1 seeds; T4) thiamethoxam (Cruiser®), dose 200 mL. 100 kg-1 seeds. All trials were performed with and without the application of the dry powder (dose 200 g. 100 kg-1 seeds).

The seeds were treated (1 kg per treatment) in a BMC (Batch Modular Coater) machine, similar to those used in industrial treatment (STI), but designed for small quantities. The seeds were put inside the machine, and then the chemicals (fungicides and insecticides), and for last, the dry powder were added.

Right after the industrial treatment, the physiological potential of the seeds was determined through the following evaluations:

Germination: it was performed with two subsamples of 50 seeds per replication, in a total of 400 seeds per treatment. The seeds were distributed on germitest paper rolls, moistened with distilled water in the proportion of 2.5 times the substrate dry mass. Next, the paper rolls were placed inside germinator at 25 ºC for 8 days. After that period, the normal seedlings were counted, and the result was expressed as percentage (Brasil, 2009BRASIL. Ministério da Agricultura, Pecuária e Abastecimento. Regras para análise de sementes. Ministério da Agricultura, Pecuária e Abastecimento. Secretaria de Defesa Agropecuária. Brasília: MAPA/ACS, 2009, 395p. http://www.agricultura.gov.br/arq_editor/file/2946_regras_analise__sementes.pdf
http://www.agricultura.gov.br/arq_editor...
).

First germination count: it was carried out jointly with the germination test. The evaluation was done five days after the test setup, when the normal seedlings were counted. The result was expressed as percentage (Brasil, 2009BRASIL. Ministério da Agricultura, Pecuária e Abastecimento. Regras para análise de sementes. Ministério da Agricultura, Pecuária e Abastecimento. Secretaria de Defesa Agropecuária. Brasília: MAPA/ACS, 2009, 395p. http://www.agricultura.gov.br/arq_editor/file/2946_regras_analise__sementes.pdf
http://www.agricultura.gov.br/arq_editor...
).

Seedling emergence in sand: it was conducted with 400 seeds per treatment, divided into four replications of 100 seeds. Sowing was performed in plastic trays (0.45 x 0.30 x 0.10 m dimensions) containing sand, in which the seeds were planted to a depth of 3 cm. The test was carried out under oven conditions, and the moisture was maintained through irrigation, according to the seedlings’ needs. The final count of emerged normal seedlings was done on the twelfth day, and the results were expressed as percentage.

Seedling total length, shoot length and root length: five subsamples of 20 seeds each were used, totalizing 100 seeds per treatment. The seeds were distributed on germination paper rolls, moistened with distilled water in the proportion of 2.5 times the dry paper mass. Then, they were kept in germinator at 25 ºC for five days (Nakagawa, 1999NAKAGAWA, J. Teste de vigor baseados no desempenho das plântulas. In: KRZYZANOWSKI, F.C.; VIEIRA, R.D.; FRANÇA-NETO, J.B. Vigor de sementes: conceitos e testes. Londrina: ABRATES, 1999. p. 2.1-2.24). Subsequently, the lengths of the seedlings (total), shoots and roots were measured with a millimeter ruler, and the results were expressed in centimeter per seedling.

The resulting data were analyzed as for normality and homoscedasticity by the Shapiro-Wilk and Hartley tests, respectively. Also, the analysis of variance was performed, and the means were compared by the Tukey’s test at a probability of 5%. The cultivars were assessed separately. The statistical analyzes were carried out with the computer software Sistema para Análise de Variância - SISVAR (Ferreira, 2014FERREIRA, D.F. Sisvar: a Guide for its Bootstrap procedures in multiple comparisons. Ciência e Agrotecnologia, v.38, n.4, p.278-286, 2014. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542014000200001&lng=en&tlng=en
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).

Results and Discussion

In the cultivar BRS 360 RR, the analysis of variance showed a significant interaction between the factors studied (seed chemical treatments and dry powder) in the variables germination, first germination count, seedling total length, shoot length, and root length. In the cultivar BRS 284, the interaction was significant in the variables seedling total length, shoot length, and root length. Additionally, it was possible to notice the independent effect of the seed chemical treatments on seedling emergence, in the cultivar BRS 360 RR, and the independent effect of the dry powder on the first germination count, in the cultivar BRS 284.

The outcome of the first germination count in the cultivar BRS 360 RR showed that seeds treated with thiamethoxam (T4) and dry powder presented a lower germination speed, in comparison with those untreated with the dry powder (Table 1). Also, seed treatment with thiamethoxam (T4) caused a reduction in the first germination count, compared to the control (T1) and the treatment with carbendazim + thiram + thiamethoxam (T2), when the dry powder was used (Table 1). On the other hand, Tavares et al. (2007TAVARES, S.; CASTRO, P.R.C.; RIBEIRO, R.V.; ARAMAKI, P.H. Avaliação dos efeitos fisiológicos de thiametoxan no tratamento de sementes de soja. Revista de Agricultura, v.82, n.1, p. 47- 54, 2007. http://www.uepg.br/Propesp/publicatio/exa/2007_3/artigo-3-Paulo-25-29.pdf
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) did not observe differences in germination nor vigor of soybean seeds treated with different doses of thiamethoxam. Similarly, Barros et al. (2001BARROS, R.G.; YOKOYAMA, M.; COSTA, J.L.S. Compatibilidade do inseticida thiamethoxan com fungicidas utilizados no tratamento de sementes de feijoeiro. Pesquisa Agropecuária Tropical, v.31, n.2, p.153-157, 2001. https://ainfo.cnptia.embrapa.br/digital/bitstream/item/28445/1/pat31n2Barros.pdf
https://ainfo.cnptia.embrapa.br/digital/...
) and Dan et al. (2011DAN, L.G.M.; DAN, H.A.; BRACCINI, A.L.; ALBRECHT, L.P.; RICCI, T.T.; PICCININ, G.G. Desempenho de sementes de soja tratadas com inseticidas e submetidas a diferentes períodos de armazenamento. Revista Brasileira de Ciências Agrárias, v.6, n.2, p.215-222, 2011. http://www.agraria.pro.br/ojs-2.4.6/index.php?journal=agraria&page=article&op=view&path%5B%5D=agraria_v6i2a939
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), in their works with beans and soybeans, respectively, verified that the germination of seeds treated with thiamethoxam did not differ in relation to the control treatment.

Table 1
Germination (G), first germination count (FC), seedling total length (STL), shoot length (SL), root length (RL) of soybean seeds from the cultivars BRS 360 RR and BRS 284 submitted to different chemical treatments, with and without the application of dry powder.

Still considering the variable first germination count, the results from the cultivar BRS 284 showed that the use of the dry powder reduced the germination speed in all treatments (Table 2). The dry powder has in its composition mica coated with titanium dioxide and natural talc-chloride, which, according to Clifton (1985CLIFTON, R.A. Talc and pyrophyllite. Washington: Bureau of Mines, 5 p, 1985. (Bulletim 675).), is a substance of hydrophilic nature. Therefore, applying dry powder over the seeds provides a fast drying of liquids, as result of a natural physical process. However, such absorption may cause water withdrawal from the seeds and damages related to imbibition. According to Toledo et al. (2010TOLEDO, M.Z.; CAVARIANI, C.; FRANÇA-NETO, J.B.; NAKAGAWA, J. Imbibition damage in soybean seeds as affected by initial moisture content, cultivar and production location. Seed Science and Technology, v.38, n.2, p.399-408, 2010. https://www.researchgate.net/profile/Jose_Franca-Neto/publication/263693071_Imbibition_damage_in_soybean_seeds_as_affected_by_initial_moisture_content_cultivar_and_production_location/links/54611bdd0cf27487b4526c72/Imbibition-damage-in-soybean-seeds-as-affected-by-initial-moisture-content-cultivar-and-production-location.pdf
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), these damages lead to problems in soybean seed germination, because they interfere in organelle structure, especially cell membranes. When the imbibition occurs fast, the cell membranes do not provide an efficient barrier against the release of solutes.

Table 2
First germination count (FC) of soybean seeds from the cultivar BRS 284, with and without the application of the dry powder.

For the variable germination, the results of the cultivar BRS 360 RR were similar to those observed in the first germination count, in which the application of the dry powder in the treatment with thiamethoxam (T4) reduced the percentage of germination, in comparison with the equivalent treatment without the dry powder (Table 1). Possibly, this has to do with a phytotoxic effect of these products when used combined, which compromised seed germination. As stated by França-Neto et al. (2016FRANÇA-NETO, J.B.; KRZYZANOWSKI, F.C.; HENNING, A.A.; PÁDUA, G. P.; LORINI, I.; HENNING, F.A. Tecnologia da produção de semente de soja de alta qualidade. Londrina: Embrapa Soja, 2016. 83p. (Documentos 380). https://ainfo.cnptia.embrapa.br/digital/bitstream/item/151223/1/Documentos-380-OL1.pdf
https://ainfo.cnptia.embrapa.br/digital/...
), the phytotoxic effect provokes atrophy of the root system, and also causes the epicotyl to get thicker, shorter, stiffer, and to present longitudinal fissures. These characteristics negatively affect the physiological quality of the seeds, as shown by the present study. Still, all germination values were above 80%, the minimum required by the Ministry of Agriculture for commercialization of soybean seeds in Brazil (MAPA, 2013MAPA - Ministério da Agricultura, Pecuária e Abastecimento. Instrução Normativa Nº 45, de 17 de setembro de 2013. Anexo XXIII - Padrões para produção e comercialização de sementes de soja. Disponível em: Disponível em: http://www.agricultura.pr.gov.br/arquivos/File/PDF/padroes_soja . Accessed on: 23 nov. 2017.
http://www.agricultura.pr.gov.br/arquivo...
).

For seedling emergence in sand, the seeds of cultivar BRS 360 RR treated with carbendazim + thiram + thiamethoxam (T2) and thiamethoxam (T4) showed a higher percentage of emergence when compared to the untreated ones (T1) (Table 3). This behavior is distinct from the all the other variables, and the difference is possibly related to the substrate: while sand was used in the emergence test, paper was used to assess the other variables. In the seedling emergence test, the contact between the chemicals on seed tegument and the developing structures of the seedling is minimized. This occurs both due to the leaching of the product in the sandy substrate, and also because of the release of the tegument in the substrate, so it does not keep direct contact with the seedling during germination, which reduces the phytotoxic effect of the products.

Table 3
Seedling emergence in sand (ES) of soybean seeds from the cultivar BRS 360 RR submitted to different chemical treatments.

As for the seedling growth, there was an interaction between the chemical treatments and the use of dry powder in both cultivars. In BRS 360 RR, the outcome was similar for the variables seedling total length and shoot length. In these cases, using dry powder favored seedling total growth and shoot growth in seeds treated with carbendazim + thiram + thiamethoxam (T2) and carbendazim + thiram (T3). However, it was harmful when associated with thiamethoxam (T4), compared to seeds untreated with the dry powder (Table 1). Also, it was possible to verify that the insecticide thiamethoxam (T4) reduced the seedling total length and the shoot length, in comparison with the other treatments that used the dry powder. Without it, the seeds treated with carbendazim + thiram (T3) presented the lowest values for the variables mentioned.

In the cultivar BRS 284, the application of the dry powder reduced seedling total length in the treatment with carbendazim + thiram (T3). On the other hand, it favored seedling growth in the treatment with thiamethoxam (T4). A comparison among the seed treatments allowed to notice that the products carbendazim + thiram (T3) and thiamethoxam (T4), respectively with and without the dry powder treatment, caused reduction in the length of the seedlings (Table 1).

Regarding the shoot length of the seedlings, in the cultivar BRS 284, the use of the dry powder in association with thiamethoxam (T4) resulted in a greater shoot growth, in relation to the equivalent treatment without the dry powder. Meanwhile, between the treatments with carbendazim + thiram (T3), the greatest values were observed in the one without the dry powder. Also, when associated with the dry powder, both carbendazim + thiram + thiamethoxam (T2) and carbendazim + thiram (T3) treatments reduced the shoot length. When the dry powder was not applied, the seeds treated with thiamethoxam (T4) showed seedlings with less shoot growth, in relation to the other treatments (Table 1).

Almeida et al. (2012ALMEIDA, A.S.; VILLELA, F.A.; MENEGHELLO, G.E. LAUXEN, L.R.; DEUNER, C. Desempenho fisiológico de sementes de aveia-preta tratadas com tiametoxam. Semina: Ciências Agrárias, v.33, n.5, p.1619-1628, 2012. http://www.uel.br/revistas/uel/index.php/semagrarias/article/view/7502
http://www.uel.br/revistas/uel/index.php...
) and Santos et al. (2014SANTOS, M.B.; SOUSA, R.M.; TEIXEIRA, W.F.; CABRAL, E.M.A.C.; CORREA, L.T.; REIS, M.R.; SOARES, J.N. Desenvolvimento inicial de plantas de soja em função do tratamento de sementes com tiametoxam. Cerrado Agrociências, v.5, p.91-97, 2014 http://revistaagrociencias.unipam.edu.br/documents/57126/579233/Desenvolvimento+inicial+de++plantas+de+soja+em++fun%C3%A7%C3%A3o+do+tratamento+de+sementes+com+tiametoxam.pdf.
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), in their respective studies on black oat seeds sowed in paper substrate, and soybean seeds planted in sand, verified that the treatment with thiamethoxam presented a phytotonic effect, which is characterized by a greater growth and development of the seedlings. According to Castro et al. (2008CASTRO, G.S.A.; BOGIANI, J.C.; SILVA, M.G.; GAZOLA, E.; ROSOLEM, C.A. Tratamento de sementes de soja com inseticidas e um bioestimulante. Pesquisa Agropecuária Brasileira, v.43, n.10, p.1311-1318, 2008. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2008001000008&lng=pt&tlng=pt
http://www.scielo.br/scielo.php?script=s...
), the insecticide thiamethoxam acts on the expression of genes responsible for the synthesis and activation of enzymes related to plant growth. Consequently, it alters the production of amino acids precursors of plants hormones that positively affect germination and vigor. Nevertheless, such effects were not observed in this work, since the results from the treatment with thiamethoxam (T4) were not superior to those of seeds untreated with this chemical. In the cultivar BRS 360 RR, the insecticide thiamethoxam (T4), whether with or without the dry powder, even damaged the physiological quality of the seeds in all variables assessed, except for the emergence in sand (Table 1).

As for the root length, seeds of the cultivar BRS 360 RR treated with carbendazim + thiram + thiamethoxam (T2) and carbendazim + thiram (T3), both added of dry powder, presented greater length in relation to the seeds untreated with the powder (Table 1). When the dry powder was used, the treatment with thiamethoxam (T4) provided lower values for the same variable, in comparison with the treatments with carbendazim + thiram + thiamethoxam (T2) and carbendazim + thiram (T3). In the seeds untreated with the dry powder, the use of carbendazim + thiram (T3) produced seedlings with smaller root length, in relation to the control treatment (T1) (Table 1).

In the cultivar BRS 284, the treatment with carbendazim + thiram (T3) and dry powder resulted in less root growth. Also, in seeds untreated with the dry powder, the treatments with carbendazim + thiram (T3) and with thiamethoxam (T4) generated the lowest values for this variable. Considering the use of dry powder within the same treatment, it was noticeable that the combination of carbendazim + thiram (T3) and dry powder reduced the root length, in relation to the seeds untreated with dry powder. In their turn, the combined use of thiamethoxam (T4) and dry powder on seeds produced the highest values of this variable (Table 1).

The cultivars exhibited different responses to the seed chemical treatments and to the use of dry powder. It probably occurred because the cultivars have distinct characteristics regarding tegument permeability, chemical composition, and other factors. Together, they might have contributed to the differences observed among the treatments.

Conclusions

The soybean cultivars showed different responses to the seed chemical treatments regarding the effects on the physiological potential.

The dry powder reduces the germination speed of seeds from the cultivar BRS 284.

In the cultivar BRS 360 RR, the treatment with thiamethoxam associated with the dry powder reduces the physiological potential of the seeds.

References

Publication Dates

  • Publication in this collection
    Apr-Jun 2018

History

  • Received
    30 Jan 2018
  • Accepted
    09 Apr 2018
ABRATES - Associação Brasileira de Tecnologia de Sementes Av. Juscelino Kubitschek, 1400 - 3° Andar, sala 31 - Centro,, CEP 86020-000 Londrina/PR - Londrina - PR - Brazil
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