ABSTRACT: Yerba mate seedling production is inefficient and costly, as the seeds have slow and low germination (<20%) and are often embryoless. Because the plant is grown in low-fertility soils, particularly in terms of phosphorus, nutritional deficiencies in the mother trees likely contribute to poor seed quality. Therefore, this study investigates the impact of phosphorus fertilization on the seed quality of yerba mate (Ilex paraguariensis A. St.-Hil.). The experiment was conducted in a seed production area with 1,822 plants, using P2O5 doses of 0, 48, 96, 182, and 288 kg.ha-1. Seed quality was assessed by the 1% tetrazolium test, thousand-seed weight (TSW), and the seed phosphorus content was determined. The results indicated no difference between treatments in seed phosphorus content or 1,000-seed weight, which was 8.0 g. However, seed viability increased with phosphorus application, with the highest quality observed in the 288 kg P2O5 ha-1 treatment. Phosphorus-fertilized mother plants were 2.58 times more likely to produce seeds with embryos. The study demonstrated that phosphorus plays a fundamental role in seed quality, improving viability and embryo presence.

ABSTRACT: Erythrina velutina Willd. is a xerophytic plant native to the Caatinga, whose seeds show heteromorphism in seed coat color, varying between reddish and orangish. This study aims to analyze the influence of seed coat color on the physical characteristics, dormancy and physiological potential of the seeds of this species. The seeds were evaluated for length, width, moisture content, hundred-seed weight, water absorption curve, first count, germination, hard seeds, shoot and root length, and shoot and root dry mass. In addition, cross-sectional fragments of 10 seeds of each color were examined by means of a scanning electron microscope (SEM), which was used to visualize the epidermis, palisade layer and parenchyma cell layers. The experimental design was completely randomized with four replications of 25 seeds in a 2 x 2 factorial scheme, considering seed coat color (orangish and reddish) and dormancy overcoming (intact and scarified seeds). The data were subjected to analysis of variance and compared by Tukey test at 5% probability level. There was no significant influence of seed coat color on the physical characterization of the seeds. It was found that reddish seeds have greater dormancy and lower physiological potential when compared to orangish seeds.

RESUMO: O cultivo de grão-de-bico (Cicer arietinum) tem se expandido no Brasil, o que demanda a oferta de cultivares registradas, adaptadas às diferentes regiões. Assim, são necessários descritores seguros visando à distinção de cultivares para a habilitação destas para a produção, beneficiamento e comercialização de sementes. Objetivou-se avaliar descritores morfológicos e moleculares de proteínas e DNA para a identificação de 10 cultivares de grão-de-bico. Os descritores morfológicos, baseados nas diretrizes da UPOV, foram avaliados em plantas cultivadas em casa de vegetação, em parcelas contendo plantas com diferentes níveis de misturas destas cultivares, em diferentes estádios de desenvolvimento. Nesta avaliação, foram calculadas as porcentagens de acerto e erro de quatro especialistas da área de sementes que desconheciam a porcentagem de misturas das cultivares. Também foram avaliadas expressões de proteínas de armazenamento, resistentes ao calor e de enzimas, em sementes das diferentes cultivares, as quais foram produzidas sob dois níveis de nitrogênio (50 e 200 kg.ha⁻¹). A caracterização das cultivares também foi realizada por meio de marcadores SSR, simples sequencia repetida. Conclui-se que que a combinação de descritores morfológicos, proteicos e moleculares é importante para a diferenciação das cultivares de grão de bico. Para os marcadores SSR, foi possível discriminar o maior número de cultivares por meio do iniciador TA-203. A expressão das proteínas não foi influenciada pelos níveis de nitrogênio, e o estádio ideal para a avaliação da pureza genética variou entre as cultivares.

ABSTRACT: Fruit storage is beneficial to growers to avoid the exposure of fruits to adverse weather conditions and infestation by pests and diseases that may affect the seed quality. This study was conducted to evaluate the influence of fruit maturity and fruit storage on the germination and vigor of bell pepper. Fruits of California Wonder cultivar were evaluated. A storage of bell pepper fruits (green mature, half-ripe (green and red) and fully-ripe (red)) at room temperature was conducted for 0, 5, 10 and 25 days. The experiment was arranged in a Completely Randomized Design with four replications. Results showed that fruit weight was higher in green mature bell peppers without storage. However, fruit storage was advantageous due to the increase in total soluble solids and dry matter. Heavier dried seeds were obtained from fruits without storage. Half-ripe with five days of storage and fully-ripe without storage exhibited the highest germination percentage and germination index of bell pepper seeds, which was higher than the standard germination rate. However, a shorter mean germination time was observed in green mature and half-ripe fruits after five days of storage. Longer and vigorous seedlings were produced from half-ripe fruits with 25 days of storage.

ABSTRACT: Global warming significantly impacts the environment, directly affecting plant development. Neoglaziovia variegata (Arruda) Mez is a Bromeliaceae endemic to the Caatinga, has highly resistant fibers used for income generation and has landscaping and medicinal potential. The study aimed to identify the thermal and saline thresholds that influence the germination of this species. In different experiments, the seeds were placed to germinate at constant temperatures between 15 and 40 °C and in substrate soaked in NaCl solution from 0 to 14 dS.m-1. The combination of thermal and salt stresses and the recovery of seeds after stress were also evaluated. All experiments followed a completely randomized design, with four replications of 25 seeds and lasted 28 days. The data were analyzed by thermal time and halotime models, establishing the thresholds for germination. The minimum and maximum temperatures for germination were 14.3 and 41.7 °C, respectively, with the ideal temperature of 31.1 °C. The germination threshold in saline medium was 16.2 dS.m-1. The seeds showed viability after being removed from the stress condition. The wide temperature range and high saline threshold show that the species can survive the most pessimistic climate change scenarios.

ABSTRACT: The success of a crop begins with the use of high-quality seeds, especially with regard to the physiological potential for germination and vigor, as well as genetic and sanitary purity, and is also fundamental for the transfer of technological innovations and genetic gains resulting from breeding works, whether traditional or the result of genetic engineering, to the field. New techniques have been studied in order to mitigate possible damage that may affect seeds until planting in the field. Thus, the objective of this study was to evaluate the effect of salicylic acid on the physiological and sanitary quality of high- and low-vigor maize seeds. High- and low-vigor seeds of the maize hybrid B2315PWU were subjected to soaking at salicylic acid concentrations of 0, 500, 1000, 1500, 2000, 2500, 3000, 3500 and 4000 uM (Micromolar). Evaluations of first count, germination, cold vigor, seedling length and mass, and sanity test were carried out. Salicylic acid doses up to 2000 uM improve germination potential in maize seeds. Treatment of maize seeds with salicylic acid may be a promising alternative for the control of Fusarium spp.

ABSTRACT: Image analysis through X-ray technique has been receiving great attention due to its importance in identifying internal damage in seeds quickly and accurately, in addition to being a non-destructive method. The aim of this study was to assess the use of X-rays to evaluate the internal morphology of seeds of green manure species. Seeds of Lupinus albus L., Cajanus cajan (L.) Millsp., Canavalia ensiformis (L.) DC. and Stylosanthes spp. were radiographed. Two hundred seeds were studied for each species, and intact seeds, seeds with mechanical damage, damage caused by insects and deteriorated tissues were recorded, considering the severity and location of the damage. The same seeds were subjected to a germination test. It was concluded that image analysis using X-ray technique was effective in detecting internal damage in seeds of some green manure species and it has relationship with negative aspects in germination.

ABSTRACT: Seed quality is routinely evaluated in the laboratory through germination and vigor tests. Although efficient, the available test methods have limitations, which are mainly associated with long evaluation times. We aimed to verify whether near-infrared (NIR) spectroscopy can categorize soybean seed lots and genotypes into predefined vigor classes based on physiological and biochemical analyses. The classes were defined based on analyses of physiological potential; the antioxidant enzymes activities; and the contents of malonaldehyde, oil and protein. The NIR spectra of individual seeds were obtained, preprocessed, and used for modeling. Classification models using the K-Nearest Neighbors (K-NN) method, Partial Least Squares Discriminant Analysis (PLS-DA), and Support Vector Machine (SVM) were obtained. The low-vigor seeds had higher malonaldehyde and oil contents and, in general, lower antioxidative enzyme activities. The best model to classify the seed quality reached 99% accuracy. The wave-length region from 1,000 to 1,250 nm was the most important for distinguishing the levels of soybean seed quality.

ABSTRACT: The quality of soybean seeds is essential for the success of the crop, with the seed coat being a vital element in protecting the embryo. The objective of this study was to understand the chemical causes and dynamics of the formation of cracks in soybean seed coat. The seed coats of five lots, with and without cracks, were used, and chemical analyses were conducted to evaluate the contents of silicon, nitrogen, phosphorus, potassium, calcium, and magnesium. Anatomical analysis was also performed; for this, the seed coats were cut and observed under a microscope to identify the cell layers and the presence of cracks. The results showed that seeds with cracks had higher phosphorus and magnesium contents and lower calcium content. Seed coat thickness ranged from 47 to 230 micrometers, and the cracks occurred preferentially in the thicker regions. The crack initiates between the palisade cells and can extend, creating air pockets that accumulate water and chemicals. Thus, cracks in soybean seed coat are related to the contents of phosphorus, calcium, and magnesium, and variations in seed coat thickness contribute to their occurrence. Cracks affect permeability and can reduce the quality of the seeds.

ABSTRACT: Understanding the changes that occur in seeds during the maturation process is essential to determine the optimal harvest time and to obtain high quality seeds. In this study, anatomical, histochemical and physiological quality data of lentil seeds at different stages of maturation were evaluated. Lentil seeds, cv. Precoz, were produced in an experimental field at the Universidade Federal de Viçosa. Pods were harvested at five stages of maturity: super-green, green, green-yellow, yellow and brown. The anatomical and histochemical characterization of the seeds was performed by light microscopy, with sections stained with Toluidine Blue, Xylidine Ponceau (XP), Lugol and Ruthenium Red. The physiological quality of the seeds was evaluated by germination, seedling emergence index (IVG), seedling emergence, electrical conductivity and accelerated ageing. During lentil seed maturation, protein, and starch reserve deposition occurs when the pods are at the green stage and stabilizes from the yellow stage. Seed coat cracks were observed in seeds from brown pods. Seed germination was similar among the different stages of maturity. Seeds from yellow pods were more vigorous than those from green and brown pods.