The aim of this study was to evaluate the effect of industrial seed treatments on the physiological potential of soybean seeds over storage. Four mixtures of agrochemical products in association with two fertilizers were tested. The agrochemical product mixtures were carbendazim/thiram + imidacloprid/thiodicarb; pyraclostrobin, thiophanate-methyl, and fipronil; thiophanate-methyl/fluazinam + bifenthrin/imidacloprid; and metalaxyl-m/fludioxonil + thiamethoxam. The two fertilizers were 7% N, 16% P2O5, 0.6% Co, and 2.5% Mo; and 1% Co, 10% Mo, and 7% P2 O5. The experiment was carried out in a completely randomized design in a split-plot arrangement in time, with four replications. The treatments were allocated in the plots, while the storage periods (0, 30, 60, 90, and 120 days) constituted the split-plots. The following tests were carried out in each period: first count of germination, germination, accelerated aging, emergence speed index in sand substrate, and final seedling emergence in sand substrate. Seed germination and vigor declined over the storage period, especially after industrial treatment. Pesticide mixtures of a carbendazim/thiram fungicide base and an imidacloprid/thiodicarb insecticide base most impaired seed physiological potential throughout storage, regardless of fertilizer use in the industrial treatment.

The objective of this work was to evaluate the degree of linear association between field emergence with the results of germination and vigor of corn seeds belonging to different initial vigor and submitted to agrochemical treatment. Following seed treatments with (i) carbendazim/thiram + imidaclopride/tiodicarbe; (ii) piraclostrobine, methyl tiophanate and fipronil; (iii) methyl tiophanate/fluazinam + bifentrine/imidaclopride; and (iv) metalaxyl-m/fludioxonil + thiamethoxam, seeds belonging to four different corn cultivars were assessed for their physiological potential. The strength of the Pearson correlation between germination and vigor tests with field emergence decreased after the chemical treatment, to a degree depending on the slurry composition, initial vigor and the test’s substrate.

This study aimed to evaluate the effect of different slurry volume of imidacloprid insecticide on the physiological potential during the storage of seeds of three soybean cultivars. A completely randomised experimental design was adopted, in a 6 × 3 × 2 factorial scheme, which treatments were six slurry volumes with imidacloprid insecticide (0, 200, 500, 800, 1 100 and 1 400 mL/100 kg of seeds), 3 soybean cultivars (SYN15630, M5947, and NS5959) and 2 storage periods (0 and 30 days after seed treatment), with four replications. The treated seeds were stored in kraft paper bags with controlled temperature and humidity. The physiological potential of the seeds was evaluated by standard germination test, electrical conductivity, accelerated aging, seedling emergence in the sand seedbed, and the field. The germination and vigor of soybean seeds were reduced during storage, especially with the increase in the volumes of the insecticide solution.

Corn has shown different degrees of positive response to inoculation with the nitrogen- fixing bacteria of the genera Azospirillum. Part of it has been attributed to the plant genotypic variation, including the root exudates, that are used by the bacteria as energy source. In this study, we grew two corn hybrids that differ for their response to Azospirillum, to investigate the effect of different exudates profiles on the bacteria growth and nitrogenase activity. Employing high performance liquid chromatography, we identified nine amino acids (asparagine, aspartic acid, serine, glutamic acid, valine, phenylalanine, threonine, tryptophan and alanine), six sugars (glucose, sucrose, xylose, arabinose, fructose and galactose) and four organic acids (citrate, malate, succinate and fumarate). The less responsive corn genotype showed reduced plant growth (root volume, shoot dry mass and shoot N content), a lower concentration of Azospirillum cells within the root tissues, a higher content of asparagine and glucose and a reduced amount of metabolites that serve as bacterial energy source (all organic acids + five sugars, excluding glucose). The genotypes did not interfere in the ability of Azospirillum to colonize the substrate, but the metabolites released by the less responsive one reduced the nitrogenase activity.

The present work aimed to evaluate the agronomic performance of wheat grown under no-tillage system and submitted to different doses and methods of inoculation with Azospirillum spp. Eight treatments were tested: 1) control; 2) half N dose; 3) full dose of N; 4) half N dose + standarded inoculation by seeds (200 mL ha-1); 5) half N dose + in-furrow inoculation (200 mL ha-1); 6) half N dose + in furrow inoculation (300 mL ha-1); 7) half N dose + inoculation by foliar spraying (200 m ha-1) and 8) half N dose + inoculation by foliar spraying (300 mL ha-1). The following parameters were evaluated: number of tillers per plant, number of grains per spike, shoot dry biomass, weight of thousand seed mass, hectoliter weight, nitrogen content in grains, nitrogen content in shoot dry matter as well as crop yield. Our results showed that the supply of the half dose of mineral N associated to foliar inoculation with Azospirillum at the dose of 300 mL ha-1 provided positive results on wheat yield, confirming the bacterial ability to fix N. However, only the full mineral N fertilization stood out as the best N fertilization management.

The objective of this work was to investigate the impact of pesticides on the survival of the plant growth-promoting bacteria Azospirillum in the surface of coated seeds as well as in the maize rhizosphere. Our results showed that the greater the time that the bacteria are in contact with the seed surface, the higher the cell mortality. In uncoated maize seeds, inoculation increased bacterial concentration in root tissues and ensured superior plant growth up to 12 hours of Azospirillum contact with the seed surface, while for the coated seeds, a similar performance was observed only up to six hours of exposure.

This study aimed to relate the smallest set of variables that compose the quality of soybean seeds lot under study, as well as to evaluate the influence of four industrial seed treatments and their respective slurry volumes on the physiological potential. The experiment was carried out in a completely randomized block design with 4 replicates and 24 treatments. The chemical treatments were: control (T1), micronutrient + polymer + drying powder (T2), bioregulator + polymer + drying powder (T3) and micronutrient + bioregulator + polymer + drying powder (T4). The seeds were stored for periods of 0, 15, 30, 45, 60 and 90 days and were subsequently evaluated for their physiological potential. In each storage period, the variable germination, first count, accelerated aging, emergence speed index, final emergence in the sand substrate, aerial part length, root length and total seedling length were evaluated. The main components of the standard germination test and first count were the ones that most contributed to explaining the variability of the original data. Increasing the volume of the slurry in the industrial seed treatment reduces the physiological quality of soybean seeds during storage.

This study aimed to compare the results of germination, vigor, and yield of high- and low-vigor soybean seeds submitted to on-farm application of biostimulant with its application via industrial treatment 60 days before sowing. The experimental design was a factorial arrangement of 6 × 2 × 2 (technology × vigor level × strategy of biostimulant application) for the laboratory experiment and of 6 × 2 (technology × strategy of biostimulant application) for the field experiment. Germination, accelerated aging, emergence in sand, seedling dry biomass, and electrical conductivity were assessed in the laboratory, while stand, one thousand-grain weight, and yield were assessed in the field. Biostimulant application in soybean seeds not coated with pesticides did not affect the physiological quality regardless of the application moment (at the day of sowing or at 60 days before sowing). However, when applied in seeds coated with fungicides and insecticides, better results of germination, vigor, and yield were obtained with the on-farm use of biostimulant.