The objective of this work was to evaluate the productive performance of soybean crops, in response to the use of seeds from lots with increasing vigor levels. The study was developed during the 2014/2015 and 2015/2016crops. In the first period, 14 treatments were evaluated, consisting of two factors, two genotypes (Syn 1059RR and NK7059RR), and seven seed lots. In the second seven treatments were considered, involving one genotype (Syn 1158RR) and seven seed lots. In both crop years, seed lots had vigor levels of 65, 70, 75, 80, 85, 90 and 95%, as determined by the accelerated aging test. The experiment was performed in a randomized block design, with a factorial scheme and five replications. Plant height, yield components, and grain yield were assessed throughout the culture cycle. The reflex of seed vigor in crop performance depended on the genotype employed. Also, there was an increase in both vegetative and reproductive performances of the crop as a function of seed vigor level. In this sense, every percentage point augmented in the vigor level of the lots resulted in a grain yield expansion of up to 28 kg.ha^-1.

The use of high-quality seeds is an important factor in the crop production system. Its benefits to the performance of plants and possible interactions with other factors - such as nitrogen fertilization - could be better understood from a multivariate analysis perspective. With this approach, the objective of this work was to evaluate the impacts of wheat seed vigor and possible interactions with nitrogen fertilization on the performance of wheat plants. The data analyzed were obtained from the average results gathered through three experimental environments, located in the department of Alto Paraná, Paraguay. High-vigor seeds with provided a better plant stand and also a greater growth in the formed tillers stage. This category also provided plants with higher performance - a condition found for dry matter weight - in the booting, flowering and milk seed stages, in the presence and absence of nitrogen fertilization. The multivariate analysis showed that plants originating from high-vigor seeds that had not been fertilized with N showed a similar performance to that of low-vigor plants, but fertilized with N. High-vigor wheat seeds provide plants with superior performance.

Seed processing is a crucial stage in obtaining high-quality seed lots. The use of spiral separator is a common method for classification of soybean seeds by shape. The objective of this work was to evaluate the effect of processing soybean seeds in a static spiral separator on their physical and physiological quality, considering prior seed size classification. A randomized block experimental design was used, in a 2 × 4 factorial arrangement consisted of two soybean cultivars (60I62 IPRO and 62R63) and four seed size classifications (unclassified, and classified in 5-, 6-, and 7-mm mesh sieves), with three replicates. The samples were cleaned, separated, and individually processed in a static spiral separator with capacity of up to 1,200 kg h^-¹. The results indicated that the 60I62 IPRO cultivar had higher percentage of discarded seeds, but better physiological potential than those of the 62R63 cultivar, denoting lower efficacy of the separator for this cultivar. Classified seeds, especially those in the 7-mm mesh sieve, had higher percentage and quality of qualified seeds. Discarded seeds from the 6- and 7-mm mesh sieves showed better physiological quality. The seed shapes of the evaluated soybean cultivars showed varied responses to processing in the static spiral separator.

Uneven maturation and green stem syndrome compromise harvest efficiency and the physiological quality of soybean seeds. Pre-harvest desiccation is a strategy to mitigate these problems, but its effectiveness depends on the interaction between herbicide, genotype, and environment. The objective of this study was to evaluate the impact of pre-harvest desiccation strategies on two soybean genotypes, NA 5909 RR (uniform maturity) and M 5947 IPRO (uneven maturity and green stem retention), in Paraguay, over two growing seasons. The strategies involved Photosystem I (PSI) inhibitors, Glutamine Synthetase (GSI) inhibitors, and Protoporphyrinogen Oxidase (PPO) inhibitors, applied alone or in combination. The PSI herbicides anticipated harvest by up to 10 days, resulting in seeds with greater germination and vigor, especially in the M 5947 IPRO genotype. Principal component analysis confirmed the superior efficacy of PSI, while Random Forest analysis highlighted that environmental factors, such as temperature and precipitation, were the main modulators of seed yield and quality, outweighing the effects of herbicides and genotypes. Rapid desiccation with contact herbicides proved to be the best strategy for advancing harvest and preserving seed quality, reducing exposure to environmental stresses. GSI showed intermediate performance, and their efficacy varied among genotypes, being less effective in preserving seed longevity due to the risk of sublethal phytotoxicity. It is concluded that herbicide selection should consider the genotype-environment interaction to optimize high-quality seed production, particularly in genotypes with uneven maturation.

The aim of this work was to evaluate the impact of soybean sowing in soil with low water availability, under two management systems, using seeds with and without chemical treatment, on the physiological quality of seeds and seedling emergence. For this, two experiments were set up, one under no-tillage system (NTS) and the other under conventional tillage system (CTS), in a randomized block design, both in a 2x6 factorial scheme, with two seed treatment conditions (with and without) and six periods of seed permanence in the soil (0, 24, 48, 72, 96 and 120 h), with four replications. Germination, vigor, percentage of abnormal seedlings and percentage of dead seeds were evaluated. Seed treatment made it possible to maintain germination at acceptable levels for up to five days of permanence of the seeds in the soil, even in CTS. Sowing in soils with low water availability can lead to reductions of 0.2 and 0.5 percentage points per hour of exposure to dry soil in germination and vigor of soybean seeds, respectively.