Quality of soybean seeds with different lignin content obtained from desiccated plants

Abstract

Soybean farmers have been using desiccation to anticipate harvesting, however, this technique is frequently questioned when used in seeds production fields, since residues left by desiccants may harm the seeds quality, especially those with fragile tegument. The aim of this study was to evaluate how desiccants applied in different times affect the quality of soybean seeds with different lignin content in the tegument. Plants of cultivars BRS Silvânia RR, BRS Valiosa RR, BRS 245 RR, and BRS 247 RR were desiccated with three commercial herbicides, besides one control treatment, in three application times, when seeds showed 30, 40, and 50% of water content. Seeds quality was evaluated performing the tests of germination, emergence, emergence speed index, accelerated aging, electrical conductivity, tetrazolium and seed yield. The lignin content in soybean seeds has high negative correlation with seed yield and with traits related to the seeds quality. In general, the plants desiccation with the herbicide Finale ® harms the seeds quality.Qualidade de sementes de soja com diferentes teores de lignina obtidas de plantas dessecadas RESUMO: Produtores de soja tem utilizado herbicidas dessecantes para antecipar a colheita, entretanto, essa prática é frequentemente questionada quando utilizada em campos de produção de sementes, uma vez que os resíduos deixados pelos herbicidas dessecantes podem prejudicar a qualidade das mesmas, especialmente daquelas com tegumento frágil. O objetivo nesse estudo foi avaliar como dessecantes aplicados em diferentes épocas afetam a qualidade de sementes de soja com diferentes teores de lignina no tegumento. Plantas das cultivares BRS Silvânia RR, BRS Valiosa RR, BRS 245 RR e BRS 247 RR foram dessecadas com três herbicidas comerciais, além de um tratamento controle, em três épocas de aplicação, quando as sementes estavam com teores de água de 30, 40 e 50%. A qualidade das sementes foi avaliada pelos testes de germinação, emergência, índice de velocidade de emergência, envelhecimento acelerado, condutividade elétrica, tetrazólio e produtividade. Para o teor de lignina das sementes de soja há alta e negativa correlação com a produtividade e os caracteres relacionados à qualidade fisiológica das sementes. A dessecação das plantas com o herbicida Finale ® prejudica a qualidade das sementes. Palavras-chave: dessecantes; Glycine max; vigorQuality of soybean seeds with different lignin content obtained from desiccated plants Rev. Bras.

Glufosinate and diquat in pre-harvest desiccation of soybean at four phenological stages, and their impact on seed quality

“…Research into the use of these two herbicides in this manner should be intensified, given the ban on paraquat. The findings of the present study and of other studies confirm the efficacy of glufosinate and diquat in pre-harvest desiccation of soybean plants (Guimarães et al, 2012;Finoto et al, 2017;Botelho et al, 2019).…”

“…However, the results may vary according to the production environment, the cultivar, and the predominant climatic conditions. The application of glufosinate (Delgado et al, 2015;Botelho et al, 2019;Zuffo et al, 2020) or diquat (Finoto et al, 2017;Ergin and Kaya, 2020) can affect soybean seed quality, especially at stages before R7. Thus, it is recommended, as a precautionary principle (in view of the potential variations), to apply pre-harvest desiccants, such as glufosinate, paraquat, carfentrazone, and diquat, in seed production fields exclusively at R7.3, as shown by Pereira et al (2015b).…”

“…Diquat has been proposed as an immediate substitute of paraquat, as it has the same mechanism of action as that of paraquat and is reported to be effective at desiccating soybean plants without reducing the yield (Zagonel, 2005). Another herbicide that can be used for this purpose is glufosinate (Pereira et al, 2015b;Botelho et al, 2019).…”

“…Other authors have also reported the negative effects of the application of different desiccant herbicides, earlier than R7, on soybean yield and other parameters (Cella et al, 2014;Coltro-Roncato et al, 2015). Glufosinate may or may not have negative effects on seed quality, depending on the application timing and dose (Pereira et al, 2015a;Botelho et al, 2019;Zuffo et al, 2020). Many stressors, such as herbicides that cause changes in soybean physiology, can affect the seed quality (Albrecht et al, 2012;Marchi et al, 2021).…”

Harvest-aid herbicides influence soybean seed yield, quality and oxidative metabolism

“…Although the plant desiccation at the R 6 and R 7 growth stages with the herbicide paraquat increase the germination rate, the vigor of the seeds derived from the desiccation at the R 6 stage is lower (Lamego et al, 2013). If soybean seeds contain a large amount of water content during harvest-aid herbicide application, it can damage seed cells due herbicide translocation into the cells (Botelho et al, 2019).…”