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ABSTRACT The traditional wheat plot seed-metering device is hampered by poor seed dispersion uniformity and a long seed falling time. To improve upon these characteristics, in this paper, we designed a double-cone combined seed-metering device. Motion analysis was conducted of wheat seeds sliding down the device, and it was concluded that the motion of wheat seed grains is affected by the cone diameter (D), cone angle (θ), and cone compartment tray rotational speed (n). The D, θ, and n were listed as test factors, and the variation coefficient of seed dispersion uniformity (VCU) and the speed of seed entry into the compartment tray (SC) were used as test indexes to conduct a test with discrete element simulation software. The results of the simulation test showed that the best performance of the seed-metering device, a VCU of 8.75% and an SC of 1.03 m s-1, was obtained when the D was 173.23 mm, θ was 45.78°, and n was 4.43r min-1, and the bench verification test was carried out under the optimal parameters, a VCU of 9.10% and an SC of 1.05 m s-1. It was shown that the simulation test was consistent with the bench test. The results of this paper provide a reference for optimizing the design of the seed-metering device and improving the seed dispersion uniformity of the wheat plot seeder.

Response of foliar rates of macronutrients in corn under nitrogen fertilization and the effects of waste of co-inoculation with Azospirillum brasilense in soybeans are evaluated. Soybean was planted in two treatments, namely, inoculation of seeds with Bradyrizobium japonicum, with and without co-inoculation with Azospirillum brasilense, followed by corn. Treatments for corn crop consisted of a combination of residual inoculation of Bradyrhizobium japonicum and the residual co-inoculation with Azospirillum brasilense within the band (main factor) applied to soybean seeds and five doses of N (0, 50, 100, 150 and 200 kg ha-1) applied to second harvest, consorted with Urochloa ruziziensis in the splits (secondary factor). Foliar rate of N, P, K, Ca, Mg and S for corn crops was determined. Efficiency of nitrogen usage (EUN), recovery of applied nitrogen (RNA), agronomic efficiency of applied N (EA) and physiological efficiency (EF) were determined. Data underwent analysis of variance and means of quality factor (inoculation) were compared by F test, whilst polynomial regression was applied for quantitative factor (N doses). Corn inoculation residue did not increase the rate of corn foliar N. However, there was an increase according to the dose of applied N. In the case of other nutrients (P, Ca, Mg), foliar increase of nutrients was detected in most doses when compared to co-inoculation and interaction between inoculation factors and N doses. There was no increase in K and S when compared to co-inoculation residue. Residual co-inoculation with Azospirillum brasilense in soybean improves corn physiology cultivated in succession and generates plants with greater production potential coupled to greater stress tolerance. [ABSTRACT FROM AUTHOR]

Rapid methods to determine the physiological quality of seeds are demands of the productive chain of this sector, in order to identify lots of low germinative potential already in its reception and/or processing. Thus, the objective was to investigate the pH test of exudate to estimate the viability of wheat seeds and to verify if it has a correlation with the standard germination test by the correlation with the germination test. It was used 10 lots of wheat seeds, from three cultivars, evaluated for the initial quality by determining the water content and viability by the germination test. The pH test of exudate was conducted with four repetitions of 50 seeds, soaked in individual cells containing 1.5 mL of deionized water, in the periods of two, three and four hours, at 20, 25 and 30 °C. After each period, a drop of indicator solution phenolphthalein was added and read the results according to the staining of the exudate present in each cell. For greater reliability, after reading the results of each tested combination, the seeds were placed to germinate. Low correlation of the exudate pH test with germination was verified for wheat, in all tested combinations, even exhibiting negative coefficients depending on the temperature/soaking period used. It can be inferred that the pH test of exudate is not efficient for a quick evaluation of the viability of wheat seeds. [ABSTRACT FROM AUTHOR]

The tetrazolium test can be an alternative to obtain fast results of the physiological potential of wheat seeds. In this context, the objective of the present study was to evaluate the efficiency of the tetrazolium test through the evaluation by analysis of digitized images in the determination of the physiological quality of wheat seeds. The experiment was carried out with 22 lots of wheat seeds, submitted to the determination of the physiological potential, including the tetrazolium test evaluated by means of digitized image analysis. For digitization, after longitudinal bisection, and staining in 0.075% tetrazolium solution, the seeds were grouped on tabletop scanner glass, stored and classified into four vigor classes. Data were submitted to analysis of variance, with means grouped by the Scott-Knott test, at 5% of significance; we also performed an analysis of the simple correlation coefficients between tetrazolium test results and other tests. The evaluation of the tetrazolium test through the analysis of digitized images grouped the lots in three levels of vigor. The method is effective in determining the vigor and viability of wheat seeds, because the possibility of expanding the images that allows precise analysis of the embryonic axis structures. [ABSTRACT FROM AUTHOR]

The application of nitrogen (N) in the correct dose and at the right time can favor the productivity and quality of wheat seeds. In this sense, the aim was to evaluate the effect of splitting and doses of nitrogen fertilization on the productivity and physiological quality of seeds of wheat cultivars. The seeds were produced at the National Soybean Research Center, in Londrina-PR, in a randomized block experimental design in a 2 × 7 factorial scheme, with four replications. The factors were constituted by two cultivars (BRS Gralha-azul and BRS Sabiá) and seven combinations of doses and splitting of nitrogen fertilization (0 kg ha-1, 40 kg ha-1 at tillering, 80 kg ha-1 at tillering, 40 kg ha-1 at sowing, 80 kg ha-1 at sowing, 40 kg ha-1 at sowing + 40 kg ha-1 at tillering, 20 kg ha-1 at sowing + 60 kg ha-1 at tillering). The following were evaluated: productivity, germination, first germination count, length and dry mass of seedlings, emergence of seedlings in sand and emergence speed index. The data were subjected to analysis of variance with comparison of means by the F test, between genotypes, and Scott-Knott, between N combinations. The effect of nitrogen fertilization on seed productivity varies with the cultivar. The application of 80 kg ha-1 N at sowing favors the vigor of the seeds for BRS Gralha-azul, and the application of 40 kg ha-1 N at sowing, or 80 kg ha-1 N at tillering favors the production of quality seeds for BRS Sabiá. The inadequate supply of N impairs the physiological quality of seeds produced. [ABSTRACT FROM AUTHOR]

The objective was to study the effectiveness of treatments to overcome dormancy of Triticum aestivum L. seeds used four seed lots (1, 2, 3 and 4), BRS Guamirim with an initial moisture content of 12.5%. The treatments were: pre-cooling temperature of 5 to 10 °C; pre-drying temperature of 30 to 35 °C; pre-drying at 50 °C for a period of undergoing exposure 72 and 96 h; imbibition of the germination test substrate using solution of gibberellic acid and potassium nitrate and untreated seeds (control). Time of radicle protrusion was assessed by soaking curve. The experimental design was completely randomized in a 4 x 6 factorial (seed lots x treatments to overcome dormancy), with five repetitions. In conclusion, lots 2 and 4 had similar performance in the imbibition curve, having a water content of 43.2 and 40.7%, respectively, after a 16 h period due to the higher degree of dormancy of lots with 30 and 38% germination; method using the thermal temperature of 30 to 35 and 50 °C (72 h) has increased efficiency in overcoming wheat seed dormancy being performed in less time when compared with test currently recommended precooling. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the use of the water restriction technique as an alternative to deep freezing for inhibiting wheat seed germination during blotter test incubation. The two techniques were compared using sixty seed samples collected in different areas of Minas Gerais state and other regions of Brazil. The water restriction established was determined by using manitol, at a potential of -1.10 MPa, based on the results of preliminary essays. The mean incidence of B. sorokiniana was not affected by any of the two techniques. Values for the incidence of Pyricularia grisea, Aspergillus ochraceus, Cladosporium cladosporioides and Epicoccum purpuracens were higher when water restriction was used. On the other hand, values for the incidence of Alternaria alternata, Drechslera triticirepentis and Fusarium graminearum were lower with water restriction. Elongation of the seed radicle can be tolerated to a certain degree during blotter test incubation and the water restriction technique is a potential alternative of the freezing technique for detecting most of the fungi associated with wheat seeds. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of seed treatment with zinc in zinc content and storability in seed as well as the components of yield of crops whose seeds were coated with doses 0, 1, 2, 3 and 4mL zinc sulfate (ZnSO4 kg-1) more fungicide, polymer and water, then were stored for six months in the environment without control of temperature and relative humidity. Before sowing the seeds were evaluated by germination test, and yield components were evaluated: number of spikelets per plant, number of grains per spikelet and grain weight per plant. After storage for six months assessed the zinc content in the seeds. The zinc coating shall not affect the viability of wheat seeds stored for six months, and further increases in the number of grains per spikelet and grain weight per plant. The zinc content in the seeds increased linearly with increasing doses of ZnSO4 via seed coating. [ABSTRACT FROM AUTHOR]

Besides increasing productivity, nitrogen fertilization may have positives effects on seed physiological quality. The objective of this study was to evaluate the effect of different forms and levels of urea in top dressing fertilization on the physiological quality of wheat seed genotypes. Seeds of three wheat genotypes (BRS 208, BRS Pardela and IWT 04008) were evaluated for four levels of nitrogen fertilization (0, 40, 80 and 120 kg.ha-1) in three forms of urea (conventional urea, urea with urease inhibitor and protected urea). The nitrogen fertilization was applied during tillering, 20 days after emergence. The seed nitrogen content, 1000 seed mass, germination and vigor (germination first count, cold test, seedling emergence in the field, dry weight of seedlings, accelerated aging and electrical conductivity) were evaluated. The IWT 04008 line and the cultivar BRS Pardela had seeds with a higher physiological quality than those of the cultivar BRS 208. The forms of urea and levels of nitrogen in topdressing did not affect seed physiological quality of the different wheat genotypes. [ABSTRACT FROM AUTHOR]

The study aimed to evaluate the influence of different concentrations of the fungicide Carboxim Tiram on the physiological quality of wheat cultivars CD 111 and CD 108 of COODETEC. The seeds were treated with the fungicide, inp the recommended commercial doses (270 mg ai L-1) at a dose above (360 mg ai L-1), below (180 mg ai L-1) and control (0 mg ai L-1) with untreated seeds. The seeds with and without treatments were planted in paper rolls and taken to the biological growth chamber (BOD) at 25 º C ± 1. The experiment was conducted in an experimental randomized block design with 4 treatments and three replications of 50 seeds per replicate. The following tests were made: germination test (TG), first count germination (PCG), electrical conductivity (EC), shoot length (SL) and root length (RL), fresh matter of shoot (FMAP) and fresh mass of root (MFR), dry matter of shoot (SDM) and root (MSR). It was observed that the fungicide produced negative interference in the germination, and that different doses of fungicide affect the performance of genotypes. In addition, the electrical conductivity increased in function of the concentration of the fungicide Thiram carboxim. [ABSTRACT FROM AUTHOR]