Near-infrared (NIR) spectroscopy has emerged as a promising tool for saving time and resources in both industrial and seed testing laboratories, as it enables the rapid pre selection of seed lots without the need for chemical reagents or the generation of waste. The application of this technique allows for the fast and accurate discrimination of seed lots according to their physiological potential. This study aimed to assess the feasibility of using the NIR technique, in combination with traditional physiological tests, to detect differences and classify crambe seed lots based on their physiological potential. Seeds from four crambe lines, including original (non-aged) seed lot and those artificially aged at 42 °C for 48 and 96 h, were evaluated. Germination and vigor of both seeds and seedlings were assessed according to standardized physiological tests. NIR spectra were collected from intact seed samples. Artificial aging induced deterioration at varying levels among the lines, particularly in the seed lot aged for 96 h, revealing differences in seed physiological potential. The spectral region between 1300 and 1400 nm was identified as the most relevant for distinguishing physiological potential levels in crambe seeds. The wavelengths that contributed most to classifying the seed lots into different levels of physiological potential were associated with biochemical compounds essential for seed quality. Therefore, near-infrared spectroscopy demonstrates strong potential for use in classifying crambe seeds according to their physiological potential.

Approximately 85000 hectares of popcorn, which is a C4 glycophytic and salt-sensitive crop, is cultivated in Brazil. Agricultural land area is decreasing because of increasing population and salinity stress, leading scientists to devise a means to develop salt-tolerant crops using genetic approaches. This study was carried out to determine the most suitable NaCl concentration for screening popcorn inbred lines for salt tolerance. Four NaCl solutions (0, 60, 120, and 180 mmol L-1) were used on four popcorn inbred lines in a completely randomized design. The experimental treatments were replicated four times in a seed-germinating chamber over seven days. Twenty-five seeds from each line were treated with Maxim® before being placed on germination paper and soaked in an appropriate NaCl solution. Significant (p < 0.05) responses of the inbred lines to different NaCl concentrations in terms of shoot length, root length, fresh and dry shoot and root weight, root diameter, root surface area and germination percentage were observed. The salt tolerance index based on dry seedling weight was significantly correlated with the other traits under 60 and 120 mmol L-1 NaCl. The most concentrated NaCl solution (180 mmol L-1) resulted in the greatest reduction in the performance of the inbred lines, indicating that NaCl is toxic to the inbred lines evaluated. Regression analysis indicated that shoot length and root length are the most significant traits for assessing salt stress tolerance in popcorn inbred lines. The results suggest that NaCl solutions of 60 and 120 mmol L-1 could be used for screening salt tolerance in popcorn, as these provide a strong ability to distinguish among the inbred lines studied.

The cultivation of Physalis peruviana has emerged as a promising alternative for small- and medium-sized producers due to its high added value and low production cost. However, information on the cultivation of this vegetable crop under Brazilian edaphoclimatic conditions is still scarce. Seedling production is one of the most critical stages for crop development, as this species does not establish well from seeds under field conditions. Therefore, this study aimed to evaluate seed germination and seedling growth of P. peruviana under different container volumes and substrate compositions. The experiment was carried out from February to March 2020 in a screened greenhouse environment, using a completely randomized factorial design. The treatments consisted of different container volumes and substrate compositions, including commercial containers of varying sizes and soil-based substrates formulated with mineral components and organic manures. Four replications were used, each consisting of seven plants. Seed emergence was favored by substrates containing well-composted cattle manure, whereas smaller container volumes reduced the emergence of P. peruviana. The greatest seedling growth, including higher stem base diameter, number of leaves per plant, leaf area, and shoot and root dry mass, was obtained in larger-volume containers filled with soil-based substrates enriched with well-composted cattle manure. Therefore, for the production of high-quality P. peruviana seedlings, the use of 400 cm3 polyethylene containers filled with a mixture of soil, sand, commercial substrate, and well-composted cattle manure in a 1:1:1:2 ratio is recommended.

ABSTRACT: Chickpea (Cicer arietinum L.) cultivation in Brazil has expanded as a winter or second-crop option, increasing demand for superior quality seeds. This study evaluated physiological performance, biochemical parameters and storability of BRS Aleppo seeds harvested at different maturation stages. Field production was performed at DAA/UFV from April to September 2020. Harvests were carried out at stages R11, R11.5, R12 and R12+7 (with 50%, 75% and 90% of pods with golden-yellow color and seven days after R12, respectively). The seeds were sealed in paper bags and stored at 23 °C ± 1.8 and 66% RH. At 0, 3, 6 and 9 months, samples were evaluated for seed moisture content, germination, accelerated aging, seedling emergence, tetrazolium test, activity of antioxidant enzymes (CAT and APX) and protein content. Chickpea seeds with higher physiological quality and storage potential were obtained when harvesting was carried out at the R11.5 and R12 stages, equivalent to 75% and 90% of the pods with golden-yellow color, respectively. Harvest delay (R12+7) reduced seed germination, vigor and storage potential, also reducing protein content and activity of APX and CAT enzymes. Storage under laboratory environment conditions for nine months reduces physiological quality of seeds, regardless of the harvest time.

ABSTRACT: The use of high-quality seeds is essential in production systems. NIR spectroscopy, combined with chemometric methods, is a promising, rapid, nondestructive, and easy-to-use tool for assessing seed physiological potential. This study aimed to analyze the feasibility of NIR spectroscopy coupled with chemometric methods to detect differences in the physiological quality of canola seeds. Seeds from eight lots of the Nuola 300, Hyola 575, and Diamond cultivars underwent initial characterization tests, seedling length tests, and X-ray analysis. For spectral acquisition, random seed samples were selected, with 12 readings taken for each cultivar. The cultivars were categorized as high (C1) and low (C2) vigor. The spectra were preprocessed using methods such as Multiplicative Scattering Correction (MSC), Standard Normal Variance (SNV), and the first and second Savitzky-Golay derivatives. These data were subsequently used to build classification models using Partial Least Squares Discriminant Analysis (PLS-DA). The model demonstrated high accuracy and kappa coefficients, with the SNV method being the best suited for the dataset. The wavelength regions between 1,004-1,064 nm and 1,698-1,907 nm were the most relevant for distinguishing seed quality levels. Analysis of near-infrared (NIR) spectra, subjected to preprocessing based on derivative methods and dispersion correction, demonstrated high efficiency in detecting variations in the physiological quality levels of canola seeds.

ABSTRACT: Physalis ixocarpa is a Solanaceae species commonly consumed in Mexico and holds significant market value in horticulture in Brazil. Although seeds are the primary means of propagation for this species, there are few studies on seed quality assessment. The objectives of this research were: (i) to investigate the potential of X-ray imaging as a method for evaluating the morphological characteristics of P. ixocarpa seeds and as a complementary approach to verifying the quality of seed lots processed by a gravity table; and (ii) to correlate the data obtained from radiographic images with the physiological potential of the seeds. Seeds from two accessions were separated using a gravity table, generating seed lots of high, intermediate-high, intermediate-low, and low density. X-ray images of the seeds were acquired, and information on tissue filling and density was correlated with physiological performance. Seeds from the high-density discharge had intact and denser tissues, as well as higher primary root protrusion speed and germination rates. Seeds from the low-density lots exhibited embryo malformations and a lower proportion of reserve tissue, resulting in reduced germination percentages and a higher occurrence of abnormal seedlings. Through radiographic image analysis, it was possible to classify P. ixocarpa seeds based on their morphological characteristics and establish correlations with their physiological potential.

The cultivation and consumption of lentils has been gaining importance in recent years due to the high nutritional value of the grain. Research related to seed technology is therefore important in providing high-quality seeds for the market. The aim of this study was to adapt the accelerated ageing test and evaluate the potential of FT-NIR spectroscopy for classifying lentil seeds based on physiological potential. Seven batches of lentil seeds were subjected to tests to characterise their physiological potential. The accelerated ageing test included the traditional method (100% RH) with an alternative method using saturated saline solution (76% RH) at 41 degrees C for 24, 36, 48 and 72 hours. NIR spectra were also obtained, taking 200 spectral readings from each batch that were individually processed for 30 seconds. Following the spectral analysis, the seeds were submitted to tests of germination and accelerated ageing to validate the technique. The PLS-DA technique was employed, using 70% of the data for training and 30% for validation. Different pre-processing methods were used, including the standard normal variate (SNV), multiplicative scatter correction (MSC), and the 1st and 2nd Savitzky-Golay (SG) derivatives. It was concluded that the accelerated ageing test at 41 degrees C for 48 hours using the traditional method (100% RH) was the most efficient way of evaluating the physiological potential of the lentil seeds. The models derived from the FT-NIR spectral data were 99% accurate in predicting the class of physiological potential of the batches.

ABSTRACT: Cedrela fissilis Vell., commonly known as cedro-rosa, is a tree species native to Brazil, with ecological and economic relevance, that exhibits seed heteromorphism associated with seed coat color. In this study, the classification of light- and dark-colored seeds using near-infrared (NIR) spectroscopy and its relationship with physiological quality was evaluated. NIR spectra were obtained, reserve compounds were quantified, and germination and vigor tests were conducted. The NIR spectra, collected from individual seeds, were preprocessed and used to develop classification models based on the Partial Least Squares - Discriminant Analysis (PLS-DA) method. The physiological and biochemical composition data were analyzed using Student’s t-test. Dark seeds showed higher thousand-seed weight, total protein content, as well as greater germination and vigor. Light seeds exhibited higher levels of reducing sugars, suggesting a lower degree of maturity or the onset of deterioration. NIR spectroscopy demonstrated high accuracy in distinguishing between light and dark seeds, especially in the spectral band near 1938 nm, whose relevance may be mainly associated with variations in total protein content. Seed coat color proved to be a reliable indicator of the physiological quality of C. fissilis seeds.

ABSTRACT: Sweet corn seeds have one or more recessive genes that increase the concentration of sugars in the endosperm at the expense of starch, which contributes to greater susceptibility to deterioration. Therefore, it is important to have rapid and automated methods for assessing their physiological potential. This study aimed to evaluate the efficiency of computerized image analysis of seedlings and near-infrared spectroscopy for assessing the physiological potential of these seeds. Seeds from five lots of the sweet corn cultivars Doce Cristal BR-402 and Superdoce BRS-400 were subjected to tests for initial quality characterization. Using the SAPL® software, the shoot, root, and total seedling lengths, as well as the uniformity, growth, and vigor indices, were determined at 3, 4, 5, and 6 days after sowing. Spectra from individual seeds were also collected using an FT-NIR spectrometer, and the same seeds were evaluated by germination test to validate the technique and obtain predictive models through PLS-DA. The preprocessing methods SNV, MSC, and first- and second-order Savitzky-Golay derivatives were applied. The total seedling and root lengths, as well as vigor indices at 3 and 4 days obtained with SAPL®, allowed differentiation of Doce Cristal BR-402 cultivar seed lots according to vigor. For the Superdoce BRS-400 cultivar, root length at 3 days and the uniformity, growth, and vigor indices at 4 days were efficient for this purpose. Data obtained by FT-NIR enabled a rapid and non-destructive estimation of the physiological potential of sweet corn seed lots, especially using the second Savitzky-Golay derivative.

Seed deterioration is among the main causes of loss in physiological potential. This study aimed to investigate the potential of Fourier transform near-infrared (FT-NIR) spectroscopy to classify lentil seeds subjected to artificial aging at 41 degrees C and 100 % of relative humidity for 24, 48, 72, 96 and 120 hours, with unaged seeds used as control. After obtaining the spectra, the seeds were submitted to germination tests, and the percentages of normal, vigorous and weak seedlings, as well as dead seeds, were recorded. From the spectral data, models were obtained using the Partial Least 70 % of the data for training and 30 % for validation. Preprocessing using the second derivative of Savitzky-Golay (SG) and the combination of the second derivative of SG + multiplicative scatter correction resulted in accuracy and kappa values in training of 0.94 and 0.92, respectively. The FT-NIR spectroscopy showed to be a promising tool for classifying artificially aged lentil seeds, considering their physiological potential.

ABSTRACT: Cultivation of chickpea has been expanding in Brazil, and defining appropriate strategies for its preservation is essential. The aim of this study was to evaluate the biochemical and physiological changes in chickpea seeds stored in different packaging materials and environmental conditions. Seeds of the BRS Aleppo cultivar were placed in impermeable (plastic) and permeable (paper) packaging and then stored under the following conditions: cold and dry storage - CS (8 ± 1.0 °C and 35 ± 1.3% RH), cooled room - CR (18 ± 1.3 °C and 62 ± 4.0% RH), and ambient conditions without climate control - AMB (24 ± 1.8 °C and 68 ± 6.7% RH). At the beginning of storage and at 3, 6, 9, and 12 months, the seeds were evaluated regarding moisture content, germination, first germination count, seedling length, accelerated aging, electrical conductivity, malondialdehyde content, and superoxide dismutase and catalase enzyme activity. Storage under CR conditions, regardless of the packaging, and under AMB conditions in impermeable packaging (plastic) maintained seed germination for up to twelve months, although vigor decreased after nine months. The physiological quality of the seeds stored under AMB conditions in porous packaging (paper) declined from six months on, showing that this condition is unsuitable for storage for 12 months. Under this condition, biochemical changes harmful to seed quality occurred, such as lipid peroxidation and reduction in SOD and CAT enzyme activity.

Abstract: Creation, adjustments and adoption of tests and tools that help in the prediction of seed storability have been highly demanded. Therefore, this work aimed to analyze the efficiency of different artificial aging times in predicting the performance of soybean seeds after storage, using the GGE biplot method. Seeds of six genotypes were subjected to storage, under refrigerated and non-refrigerated conditions, and artificial aging, being artificially aged for periods of 0, 48, 96 and 144 hours. Seeds freshly harvested and after natural and artificial aging were subjected to germination and vigor tests. The experiments were analyzed separately, using means test, regression analysis and model identity test, and together, using the GGE biplot method. Artificial aging at a temperature of 41 °C for 96 hours has the potential to be used to predict the performance of soybean seeds after eight months of storage. The GGE biplot is a method that can be used as a tool to analyze the relationships between aging environments and visualize the ranking of genotypes regarding the performance of seeds subjected to natural and artificial aging.

ABSTRACT The drying process is paramount for maintaining seed quality, where the temperature during this process directly influences germination and vigor, especially for vegetable species harvested with high moisture content. This research aimed to determine and model the drying curves of S. aethiopicum (cultivar Tinguá-verde-claro) seeds at temperatures of 35, 38, 41, and 44 ºC, as well as to evaluate the physiological quality of the seeds after drying. A completely randomized design was used, with four drying temperatures (35, 38, 41, and 44 ºC) and four replicates. Nine mathematical models were fitted using the non-linear regression analysis by the Gauss-Newton method, and the goodness of fit was assessed based on the magnitude of the coefficient of determination (R2), chi-square test (χ2), relative mean error (P), and estimated mean error (SE). Seed quality was evaluated by germination test (G), electrical conductivity (EC), and accelerated aging (AA). The Modified Midilli model best represents the drying curves of S. aethiopicum seeds at the studied temperatures. Seeds with higher germination and vigor, meaning lower electrical conductivity values and higher germination rates after accelerated aging, are achieved through drying at 35 and 38 ºC.

Understanding cultivars' physiological traits variations under abiotic stresses is critical to improve phenotyping and selections of resistant crop varieties. Traditional methods of accessing physiological traits in plants are costly and time consuming, which prevents their use in breeding programs. Spectroscopy data and statistical approaches such as partial least square regression could be applied to rapidly collect and predict several physiological parameters at leaf-level, allowing phenotyping several genotypes in a high-throughput manner. We collected spectroscopy data of twenty soybean cultivars planted under well-watered and drought conditions during the reproductive phase. At 20 days after drought was imposed, we measured leaf pigments content (chlorophyll a and b, and carotenoids), specific leaf area, electrons transfer rate, and photosynthetic active radiation. At 28 days after drought imposition, we measured leaf pigments content, specific leaf area, relative water content, and leaf temperature. Partial least square regression models accurately predicted leaf pigments content, specific leaf area, and leaf temperature (cross-validation R2 ranging from 0.56 to 0.84). Discriminant analysis using 54 wavelengths was able to select the best-performance cultivars regarding all evaluated physiological traits. We showed the great potential of using spectroscopy as a feasible, non-destructive, and accurate method to estimate physiological traits and screening of superior genotypes.

The identification of soybean genotypes tolerant to soil compaction makes it possible to reduce productivity loss under stress conditions. Added to this, the prior selection of these genotypes will result in greater assertiveness in the positioning of cultivars in the field. Thus, the objective was to evaluate the susceptibility of soybean genotypes to compaction in greenhouse and field conditions; verify which characteristics of seedlings under high resistance to root penetration are correlated with crop production in compacted soil; and to validate the substrate mechanical impedance method for evaluating the susceptibility of plant genotypes to soil compaction. Seeds of 20 genotypes were sown in a substrate mechanical impedance system under controlled conditions. The characteristics evaluated were total root length, total root surface area, mean root diameter, total root volume, taproot length, shoot length, root dry matter and seedling shoot dry matter. In the field experiment, half of the planting area was compacted, constituting two treatments, soil with and without compaction. The percentage of seedling emergence, initial plant height, stem diameter, number of nodes, internode length, number of lateral branches, shoot dry matter, final plant height, absolute and relative growth rate, number of pods, weight of 100 seeds and grain yield. In addition, the number of days between soybean sowing until plant flowering and grain harvest was recorded according to genotype and soil compaction level. In a controlled environment, genotypes tolerant to soil compaction show greater plasticity of root characteristics and smaller alterations in the shoot of seedlings. In the field, these genotypes show smaller reductions in growth rate, height, number of pods and grain yield. The shoot dry matter and the root dry matter of soybean seedlings in a mechanical impedance system present a positive and negative correlation, respectively, with soybean yield in compacted soil, indicating that the genetically determined susceptibility to soil compaction stress was similar throughout ontogenesis. The substrate mechanical impedance system used to evaluate the performance of soybean seedlings under stress, facilitates the decision-making in breeding programs focused on identifying genotypes expressing soil compaction tolerance.

Water deficit is the main limiting factor in rainfed agricultural production, negatively affecting germination and vegetative development. The objectives of this work were to characterize inbred lines for drought tolerance, to identify the most important root and shoot morphological traits for discriminating genotypes, to compare the efficiency of identifying contrasting inbred lines using uni- and multivariate methods, and to evaluate the effectiveness of identifying drought-tolerant genotypes at seedling and vegetative stages. We assessed 28 popcorn inbred lines and three maize single crosses, two drought-tolerant and one drought-sensitive. At the seedling stage, drought was induced on germitest paper moistened with polyethylene glycol 6000. At the vegetative stage, we applied water stress using lysimeters. We measured root and shoot morphological traits under water stress and no stress and processed the relative values. Uni- and multivariate methods, alone or in combination, were equally efficient for identifying contrasting inbred lines for drought tolerance. The confidence interval and Dunnett’s test worked very well when contrasting controls were included. Principal component analysis allowed to discriminate genotypes and identify the most important traits for discriminating them. At the seedling stage, inbred line 22-1824-2 was the most drought-tolerant and 22-1877-3 the most sensitive. At the vegetative stage, inbred lines 22-1920-1 and 22-1867-4 were the most tolerant and 22-1860-5 was the most sensitive. Root length, volume, dry weight, and surface area, as well as water content, were the most important traits for discriminating genotypes. Due to distinct tolerance mechanisms, drought tolerance should be assessed at both stages.

Physalis peruviana holds significant economic value, making it crucial to determine optimal cultivation conditions, particularly concerning seed germination under varying water and temperature conditions. Therefore, this study aimed to assess the impacts of heat and water stress on the germination and vigor of P. peruviana seeds. The study was divided into two trials: the first examined the effect of constant temperatures of 10, 15, 20, 25, 30, 35, and 40 °C and alternating temperatures of 20 °C during the dark period and 30 °C during the light period (control) on seed germination and vigor. The second trial investigated germination and vigor under different water and thermal conditions using various osmotic potentials (0; −0.3; −0.6; and −0.9 MPa) and two temperatures (constant 30 °C and alternating 20 °C during the dark period and 30 °C during the light period). Both trials used a 16 h photoperiod. The germination tests revealed optimal (30 °C), moderate (20/30 °C), minimal (20 °C), and inhibited (40 °C) temperatures for the species’ germination. It was found that the first germination count could be conducted on the seventh day after sowing. Low water availability had negative effects on seed germination and vigor, especially at osmotic potentials below −0.45 and −0.61 MPa, combined with temperatures of 30 and 20/30 °C, respectively. Severe water stress, with osmotic potentials equal to or below −0.9 MPa, completely inhibited seed germination and vigor. Reduction in water potential and increased temperature resulted in a significant decrease in the percentage, speed, and quality of P. peruviana germination. These findings indicate that the species does not tolerate extreme temperatures, whether low (less than 15 °C) or high (greater than 35 °C), nor water stress with osmotic potentials lower than −0.45 MPa, much less the combination of these factors.

ABSTRACT: Near-infrared (NIR) spectroscopy is a promising tool for optimizing seed analyses quickly and assertively. The aim of this study was to investigate the viability of NIR in association with chemometric methods in classification of soybean seed lots regarding their physiological potential. We evaluated 372 soybean seed lots for vigor and obtained NIR spectra from seed samples. The original spectra were pre-processed by the following methods: Standard Normal Variate (SNV), SNV + 1st and 2nd derivatives, Gap-segment derivative, and Savitzky-Golay for the first- and second-degree derivatives, as well as combinations of the methods. The lots were divided into Class I (≥ 85% germination after accelerated aging) and Class II (< 85% germination after accelerated aging); and the pre-processed spectra were used to build classification models through the following methods: K-nearest neighbors (KNN), Partial Least Squares - Discriminant Analysis (PLS-DA), Naive Bayes (NB), Random Forest (RF), and Support Vector Machine (SVM). The PLS-DA model showed greater classification accuracy and kappa, followed by SVM. The lowest accuracy values were obtained for the NB and RF models. The regions between the wavelengths 1,000-1,200 nm and 2,200-2,500 nm were the most important for distinguishing the quality levels of soybean seeds.

Understanding cultivars' physiological traits variations under abiotic stresses is critical to improve phenotyping and selections of resistant crop varieties. Traditional methods of accessing physiological traits in plants are costly and time consuming, which prevents their use in breeding programs. Spectroscopy data and statistical approaches such as partial least square regression could be applied to rapidly collect and predict several physiological parameters at leaf-level, allowing phenotyping several genotypes in a high-throughput manner. We collected spectroscopy data of twenty soybean cultivars planted under well-watered and drought conditions during the reproductive phase. At 20 days after drought was imposed, we measured leaf pigments content (chlorophyll a and b, and carotenoids), specific leaf area, electrons transfer rate, and photosynthetic active radiation. At 28 days after drought imposition, we measured leaf pigments content, specific leaf area, relative water content, and leaf temperature. Partial least square regression models accurately predicted leaf pigments content, specific leaf area, and leaf temperature (cross-validation R2 ranging from 0.56 to 0.84). Discriminant analysis using 54 wavelengths was able to select the best-performance cultivars regarding all evaluated physiological traits. We showed the great potential of using spectroscopy as a feasible, non-destructive, and accurate method to estimate physiological traits and screening of superior genotypes.

This work aimed at investigating the viability of near infrared spectrometry (NIR), associated with chemometric methods, in order to identify differences at the levels of vigor of naturally and artificially aged soybean seeds. Seeds of six soybean genotypes were analyzed when freshly harvested, after natural aging in storage for eight months, and after artificial aging at the temperature of 41 °C for 96 hours. The seed moisture content, germination potential and vigor were evaluated. Also, there were measured the content of protein, oil and of the fatty acids: palmitic, stearic, oleic, linoleic and linolenic. The NIR spectra were obtained from the freeze-dried and grinded seeds. The natural and artificial aging of the seeds promote deterioration at distinct levels, reflecting in differences in seed vigor. The regions of the electromagnetic spectrum between wavelengths of 1000-1200 nm, 1350-1450 nm, 1800-1900 nm and 2300-2400 nm are important to distinguish the levels of quality of the soybean seeds. The contents of oil and protein have a relationship with the physiological quality of the seeds. Also, the most relevant wavelengths for the classification of seed vigor present a relationship with these compounds. NIR spectroscopy, in combination with chemometric methods, presents potential to be used in the classification of soybean seeds regarding their physiological quality.