Productivity and physiological quality of seeds with burn down herbicides at the pre harvest of bean crops

Abstract

-The physiological quality of bean seeds is influenced by the production environment and management practices employed during cultivation. The objective of this study was to evaluate the productivity and physiological quality of bean seeds after desiccant applications at different times at pre-harvest. A randomized block design was used, with a factorial (3x3) + 1 arrangement, where the application of three desiccants was tested: glyphosate (960 g a.i. ha -1 ), paraquat dichloride (240 g a.i. ha -1 ) and glufosinate ammonium (400 g a.i. ha -1 ) + mineral oil, applied three times (days after flowering -DAF), and a control without herbicide in four replications. Seed quality was determined by the following tests: germination, first count, seedling emergence speed rate, accelerated aging, electrical conductivity and seedling dry biomass. Seed yield was not influenced by either herbicides or time of application. Regardless of time of application, the lowest percentage of normal seedlings after the germination, first count and accelerated aging tests was observed in seeds desiccated with the herbicide glufosinate ammonium. The herbicide glyphosate reduces seedling vigor. The times of application of the product paraquat dichloride did not affect the germination and vigor of bean seeds.Index terms: Phaseolus vulgaris L., herbicide, germination.Produtividade e qualidade fisiológica das sementes com dessecação na pré-colheita do feijoeiro RESUMO -A qualidade fisiológica de sementes de feijão é influenciada pelo ambiente de produção e por práticas de manejo empregadas durante o cultivo. O objetivo do trabalho foi avaliar a produtividade e qualidade fisiológica de sementes de feijão, após aplicações de herbicidas dessecantes em diferentes épocas na pré-colheita. Utilizou-se o delineamento de blocos ao acaso, em esquema fatorial (3x3) + 1, onde se testou a aplicação de três herbicidas dessecantes: glyphosate (960 g de ia.ha -1 ), dicloreto de paraquat (240 g de ia.ha -1 ) e glufosinato de amônio (400 g de ia.ha -1 ) + óleo mineral, aplicados em três épocas (dias após o florescimento -DAF), mais uma testemunha sem aplicação de herbicida, em quatro repetições. A qualidade fisiológica das sementes foi determinada por meio dos testes de germinação, primeira contagem, índice de velocidade de emergência de plântulas, envelhecimento acelerado, condutividade elétrica e biomassa seca de plântulas. A produtividade de sementes não é influenciada pelos herbicidas e épocas de aplicação. Independente da época de aplicação, a menor percentagem de plântulas normais no teste de germinação, envelhecimento acelerado e primeira contagem, é de sementes dessecadas com o herbicida glufosinato de amônio. O herbicida glyphosate reduz o vigor de plântulas. As épocas de aplicação para o produto dicloreto de paraquat não afetam a germinação e o vigor das sementes de feijão.Termos de indexação: Phaseolus vulgaris L., herbicida, germinação.

<b>Split application of molybdic fertilizer at the reproductive stage of common bean increases the molybdenum content in seed

“…For SMoC calculation, seed Mo concentration in μg g -1 was multiplied by the average mass of one dry seed (in g). Seed quality was evaluated by standard germination and accelerated aging tests according to methodology described by Pinto, Basso, Kulczynski, and Bellé (2014). In these two tests, a randomized complete block design with four replications was used.…”

Physiological Quality of Carioca Bean Seeds Submitted to the Application of Desiccant Herbicides in Two Periods

“…Lamego et al (2013), in studies with soybean seeds, also noticed a reduction in germination percentage in later desiccations. Pinto et al (2014) found a smaller amount of normal seedlings in the germination test when using the herbicide ammonio-glufosinate for bean desiccation. Domingos et al (1997) observed reduction in germination and vigor when this same herbicide was applied to carioca bean seeds with water content between 37% and 42%, using the dose of 400 g ha -1 .…”

“…There was no difference in the application of ammonium-glufosinate in relation to the additional (harvested with 18% water) at 50%, 75% and 100% doses compared to the recommended average dose of this herbicide (1.9 L ha -1 ), regardless of the time of application (Table 3). Pinto et al (2014) observed that ammonium-glufosinate reduces the number of normal bean seedlings, compared to the control treatment (without desiccant application, harvested together with the other treatments), for all application times. Tavares et al (2015) found a linear reduction in the percentage of normal bean seedlings in the first count, with increasing doses of the herbicide saflufenacil, in the evaluations performed after harvest, corroborating the results of the present study.…”

“…However, before opting for the application of these products, one should be aware of the mode of action and the possibility of accumulation of residues in the seeds, which may compromise the physiological quality and even make them unviable for commercialization (Bulow and Silva, 2012). In this sense, several authors evaluated the use of herbicides for desiccation and found damage to seeds of soybean (Marcandalli et al, 2011;Botelho et al 2016), beans (Kappes et al, 2012;Pinto et al, 2014) and wheat (Bellé et al, 2014).…”

The Time of Application of Maturing Herbicides Affects the Physiological Quality of Canola Seeds

“…These results corroborate with those found with Marcandalli (2011) when observing that glyphosate negatively influenced the physiological quality of soybean seeds. There were fewer normal seedlings in the germination test when the ammonium glufosinate was used in the bean crop (Pinto et al 2014 2014), where the minimum germination required for the marketing of canola seeds is 80%. With the exception of the additional control in the second season of application, which germinated 94%, all other treatments, in both seasons, obtained inferior results.…”