HARVEST TIMES WITH CHEMICAL DESICCATION AND THE EFFECTS ON THE ENZYMATIC EXPRESSION AND PHYSIOLOGICAL QUALITY OF SOYBEAN SEEDS

Alan Mario Zuffo,Paulo Eduardo Teodoro,Everson Reis Carvalho,Jorge González Aguilera

doi:10.1590/1983-21252020v33n209rc

Alan Mario Zuffo, Paulo Eduardo Teodoro + Show 2 more

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https://doi.org/10.1590/1983-21252020v33n209rc

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Abstract

ABSTRACT This study aimed to evaluate the effect of chemical desiccants and harvest times on the enzymatic expression and physiological quality of soybean seeds. The experiment was carried out in a randomized block design with four replications, in a factorial scheme (4 × 3 + 1) with four desiccants (paraquat - 2 L ha-1, ammonium glufosinate - 2 L ha-1, diquat - 1.5 L ha-1, and saflufenacil - 40 g ha-1). These were applied at the phenological stage R7.1 (beginning of leaf yellowing) and at three harvest times (0, 14, and 28 days after the phenological stage R8). There was also a control treatment (no desiccant, harvested at R8). The physiological quality of soybean seeds and the enzymatic expressions of malate dehydrogenase, alcohol dehydrogenase, esterase, isocitrate lyase, and superoxide dismutase were evaluated in laboratory tests. Seeds harvested at the R8 + 14 stage led to the highest losses in seed quality. However, the 50 mm rainfall also affected seed deterioration. The desiccants diquat and paraquat provided the lowest and the highest damage to the seed physiological quality, respectively. The expression of the enzymes alcohol dehydrogenase, esterase, and isocitrate lyase were efficient and had an adequate correlation with the physiological quality. Malate dehydrogenase and superoxide dismutase had no satisfactory relation with the physiological tests performed with soybean seeds.

Highlights

IntroductionSoybean seed quality can be determinant in the expansion of current markets and depends on the field management and the ability of the producer to deal with biotic and abiotic stresses that affect the crop
Previous reports have shown the isolated effect caused by the harvest time delay on the soybean crop (XAVIER et al, 2015; ZUFFO et al, 2017a,b) and by the use of desiccants (MARCANDALLI; LAZARINI; MALASPINA, 2011; LAMEGO et al, 2013) as a management strategy
The use of desiccants and harvest times affects the physiological quality of soybean seeds regarding germination, electrical conductivity and accelerated aging

Summary

Introduction

Soybean seed quality can be determinant in the expansion of current markets and depends on the field management and the ability of the producer to deal with biotic and abiotic stresses that affect the crop. The vigor and germination of soybean seeds is influenced by the genetics of the crop, the environment, and agricultural practices, among other factors (MOREANO et al, 2013). Seed quality is related to the moisture content in the seed when it gets close to the harvest time. When the seed is near to its maturation, the water content naturally decreases, or artificially decreases when we apply desiccants to the plants to homogenize the crop and affect the moisture content of the seeds (MOREANO et al, 2013). The use of desiccants and the selection of the best harvest times are determinant factors at this stage (LIMA et al, 2007)

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