Abnormal Seedlings Research Articles

Machine Learning Insights into Ascorbic Acid-Enhanced Germination of Black Cumin (Nigella sativa L.) under Cadmium Stress

AbstractThe objective of the present work is to study the impact of seed priming with varying concentrations of ascorbic acid (vitamin C) on the germination process of black cumin (Nigella sativa) under cadmium (Cd) stress. As expected, Cd had a great effect on germination rates and seedling growth. However, the application of ascorbic acid during seed priming effectively alleviated Cd stress and significantly increased seed vigor. Primed seeds exhibited markedly elevated final germination percentage, germination index, mean germination time, seedling length, seedling vigor index, and reduced abnormal seedling percentage. Additionally, vitamin priming reduced membrane lipid peroxidation, in treated seeds. Moreover, seed priming elicited a considerable increase in peroxidase and catalase activity, thus mitigating stress effects and augmenting seed vitality. Our experimental data allowed us to establish 100–150 mg/L as the optimal concentration range for ascorbic acid in seed priming of black cumin. These insights were further corroborated through modeling techniques based on supervised machine learning. Notably, XGBoost emerged as a proficient tool for predicting final germination percentage, mean germination time, seedling vigor index, abnormal seedling percentage, and peroxidase activity, while SVR demonstrated aptitude in forecasting catalase activity and germination index. The Gaussian method exhibited superior performance in predicting malondialdehyde content. These comprehensive findings substantiate the premise that vitamin priming with ascorbic acid serves as a promising strategy to ameliorate germination outcomes under Cd-induced stress conditions.

Conservation implications and genetic significance of abnormal seedlings: case studies from the Western Ghats, India

Conservation implications and genetic significance of abnormal seedlings: case studies from the Western Ghats, India

The effect of seed packaging materials, storage period and conditions on the physiological sorghum seedlings

Seed quality is fundamental to agricultural productivity and sustainability. Sorghum, as a versatile crop with a wide range of applications, requires high-quality seeds for optimal production. Understanding the seed storage condition, storage period and packaging materials on seed physiological quality is a basis of field crop establishment. This study aimed to evaluate the impact of packaging materials, storage conditions, and storage periods on the physiological quality of sorghum seedlings. One hundred grams of sorghum seed from 5.4 kg of cleaned sorghum seeds were packed in polyethylene bags, polypropylene bags, and aluminium foil. The seeds in packaging materials were stored at 3 different temperatures for 2, 4, and 6 months and the sample of ten grams was taken every 2 months of storage time for germination test. The data on normal seedlings, abnormal seedlings lengths, and seedling dry weight were recorded. The results showed that polyethylene bags at 10°C and 2 months of storage preserved seedling physiological quality more than aluminium foil and polypropylene bags. This may be attributed to the impervious properties of polyethylene hence preventing oxidative reactions and seed deterioration. To guarantee the successful field establishment and strong plant stand of sorghum crops, findings advise seed producers and farmers regarding appropriate seed storage procedures.

Time of Application of Desiccant Herbicides Affects Photosynthetic Pigments, Physiological Indicators, and the Quality of Cowpea Seeds.

Chemical desiccation is widely used in agriculture to anticipate harvest and mitigate the effects of adverse environmental conditions. It is applied to both grains and seeds. Although this practice is widely used, there are still significant gaps in understanding the effects of different herbicide application times on seed quality and plant physiological responses. The objective of this study was to evaluate the effects of different herbicide application times on cowpea, focusing on seed quality, physiological responses, and biochemical composition, including chlorophylls, carotenoids, sugars, and proline, under nocturnal desiccation. In the first experiment, eight herbicides and two mixtures were applied at night: diquat, flumioxazin, diquat + flumioxazin, glufosinate ammonium, saflufenacil, carfentrazone, diquat + carfentrazone, atrazine, and glyphosate. All of the tested herbicides caused a reduction in normal seedling formation, with the diquat + carfentrazone combination resulting in 100% abnormal seedlings. A significant decrease in chlorophyll levels (chlorophyll a: 63.5%, chlorophyll b: 50.2%) was observed using diquat, which indicates damage to photosynthetic processes, while the carotenoid content increased. Total soluble sugars and proline were also negatively impacted, reflecting physiological stress and metabolic changes in seedlings. In the second experiment, three application times were tested with diquat, diquat + flumioxazin, and diquat + carfentrazone. Nocturnal application showed the most significant reduction in chlorophyll levels and increased carotenoid levels. Application at noon and late afternoon also significantly changed the soluble sugar and proline levels. These results indicate that the herbicide application time directly influences the seeds' physiological quality.

The impact of chitosan nanoparticles on seedling and germination attributes and enzymatic activity of guar (Cyamopsis tetragonoloba L.) under osmotic stress

This research was conducted to examine the effects of nano chitosan particles on seed germination and seedling growth of guar (Cyamopsis tetragonoloba L.) under osmotic stress conditions. This experiment was conducted in a factorial layout based on a completely randomized design with two factors and four replications. The experimental factors included: osmotic stress at five levels (0, −3, −6, −9 and −12 bar) and seed priming with nano chitosan particles at five concentrations (0, 50, 100, 200, and 300 ppm). The evaluated parameters in this study were alometric traits and enzymatic activities including proline, catalase, ascorbate peroxidase, superoxide dismutase, and total soluble sugar, as well as the content of chlorophyll a, b, and carotenoids. The results indicated the significant effect of most of the studied quantitative and qualitative traits. The highest values of seedling, plumule and radicle length (48.20, 17.79 and 30.15 mm, respectively), and the fresh weight of seedlings and plumule (0.9743 and 0.9192 g, respectively) were observed at a concentration of 200 ppm of chitosan nanoparticles. The highest amount of all studied parameters observed under non-stress conditions (control), and the lowest values of them obtained in −12 bar of osmotic stress. Furthermore, by increasing of osmotic stress levels, germination percentage and rate and seed vigor showed a decreasing trend about 56, 83 and 95% compared to the control. Besed on the interaction effects, the maximum values of seedling and plumule length were achieved with the application of 200 ppm chitosan nanoparticles in combination with no osmotic stress. Under non-osmotic conditions, concentrations of 300, 100, and 200 ppm chitosan led to the highest values of germination percentage and rate and seed vigor, respectively. Additionally, the highest percentage of normal seedlings (94%) and the lowest percentage of abnormal seedlings (zero) were obtained under the application of 200 ppm of nano chitosan and no osmotic stress. In relation to qualitative traits, the lowest values of soluble sugar and proline were obtained at the osmotic level of −12 bar. Moreover, the application of 200 ppm of nano chitosan and −6 bar of osmotic stress resulted in the highest levels of catalase, superoxide dismutase, ascorbate peroxidase, chlorophyll a, b, and carotenoids. As a whole, the results of the study demonstrated that seed priming with chitosan nanoparticles can reduce the negative effects of drought stress on guar seedlings. In addition, application of 200 ppm of this substance was the most suitable treatments that improve most quantitative and qualitative indices of guar. Keywords: Enzymatic activity, Nano particles, Priming, Seed structure.

Pollen morphology and reproductive biology of Calophyllum brasiliense Cambess. (Calophyllaceae)

Pollen morphology and the reproductive biology of Calophyllum brasiliense were investigated in Parque Estadual das Fontes do Ipiranga, São Paulo, Brazil. The study encompassed pollen analyses using light, scanning, and transmission electron microscopy. Additionally, we collected data on reproductive biology, main visitors/pollinators, fruit set, and seed germination. The species exhibits individuals with perfect flowers (hermaphrodites) as well as male individuals with staminate and perfect flowers. Flowering occurs in October and November, and flowers have diurnal anthesis and pollen as a floral resource. Pollen grains are monads of medium size, isopolar, oblate-spheroidal to prolate-spheroidal, 3-(4)-zonocolporate, with exine fossulate-perforate with supratectal microechini. Hermaphrodite individuals have the highest proportion of malformed pollen due to their reduced grain size. The pollen grains from the hermaphrodite individuals displayed a low viability (0.06%), while those from male individuals had higher viability (66.38% and 55.78% for perfect and staminate flowers, respectively). The stigma was receptive throughout the anthesis period. Cross-pollination between perfect flowers of male and hermaphrodite individuals resulted in 8.80% success in fruit set, but led to the development of one abnormal seedling. Cross-pollination between staminate flowers and perfect flowers of hermaphrodite individuals showed a 7.70% success rate and the control group showed an 8.00% success rate, both groups leading to the development of normal seedlings. This tree species shows relatively low reproductive success and relies on pollinators (mainly Apis mellifera, Paratrigona subnuda, Tetragonisca angustula, and Halictidae sp. 1) for the setting of fruits and seeds.

Investigation of biological-rhythm patterns: physiological and biochemical effects in herbaceous plants exposed to low-level chronic radiation – part 1: nonirradiated seeds

Hypothesis Because reactive oxygen species are involved in the regulation of biological rhythms, we hypothesized that intra-annual variability of seed progeny quality at low doses of ionizing radiation (LDIRs) would differ from that of background plants. Materials and methods We conducted 12 consecutive experiments using the roll culture method by germinating seeds (monthly for 3 weeks) of six herbaceous plant species (Bromus inermis, Geum aleppicum, Plantago major, Rumex confertus, Silene latifolia, and Taraxacum officinale) growing under conditions of chronic radiation in the East Ural Radioactive Trace (EURT). We assessed physiological (seed viability and abnormality frequency) and biochemical (low-molecular-weight antioxidants, LMWAs) parameters of seedlings. Results Total absorbed dose rates of maternal plants (TADRplants) and seed embryos (TADRseeds) in the EURT exceeded background levels by 1–3 and 1–2 orders of magnitude, respectively. Nonlinear dependencies on TADR were mainly characteristic of physiological and biochemical parameters. For most populations of the studied species (B. inermis, G. aleppicum, R. confertus, and S. latifolia), seedling survival and root length decreased in the autumn–winter period, while the frequency of abnormal seedlings increased. The content of LMWAs could be ranked as R. confertus > B. inermis > G. aleppicum > S. latifolia, in good agreement with the presence of anthocyanin pigmentation in the plants. The lowest synthesis of antioxidants in seedlings was observed in winter. A high LMWA content promoted growth and reduced the frequency of abnormal seedlings. Conclusions These results underscore a multistage nature of the impact of LDIRs on intra-annual biological rhythms in plants. High heterogeneity in reference group ‘wild grasses’ and diversity of their radiobiological effects should help to develop methods of radiation protection for natural ecosystems and facilitate approaches used by the International Commission on Radiological Protection. Highlights Absorbed dose rates for six plant species in the East Ural Radioactive Trace (EURT) area range from 0.11 to 73.89 µGy h−s (plants) and 0.11 to 6.88 µGy h−s (seed embryos). Intra-annual rhythms of physiological and biochemical parameters in the EURT zone differ from those in background seedlings. Plants in the EURT area exhibit a wide range of trait variability, asynchrony of the manifestation of the effects, nonlinear dose–response relations, and hormesis. A high content of low-molecular-weight antioxidants (LMWAs) is associated with low frequency of developmental abnormalities and high viability of seed progeny.

Production of Seedlings of Corymbia citriodora Inoculated with Endophytic Bacteria

This study aimed to evaluate the effect of inoculants of endophytic bacteria producing indoleacetic acid (IAA) on the physiological quality of seeds and the production of seedlings of Corymbia citriodora (Hook.) KD Hill & LAS Johnson. In the physiological quality test of the seeds, the treatments used were individual inoculation with Priestia megaterium, Exiguobacterium sibiricum, Pantoea vagans strain 45URP4-1, and Bacillus sp.; joint effect of the four strains (mix); inoculation only with the carrier (cassava starch and activated charcoal); carrier with 1.0 μg mL−1 of IAA; and non-inoculated control without IAA and without a carrier. In the production of seedlings in a greenhouse, the treatments were the same, except for the mix, which was replaced by P. vagans strain 7URP1-6 (Pvs7), as inoculation with the mix increased the number of abnormal seedlings. In the physiological quality test of seeds, seeds inoculated with the bacteria individually did not have the physiological quality impaired and the carrier created a microenvironment around the seeds, benefiting germination percentage, germination speed index, average germination time, and average germination speed. In the greenhouse, seedlings inoculated with Pvs7, P. megaterium and E. sibiricum were taller, with a larger stem diameter and dry mass of shoot, roots, and total. Seeds inoculated with E. sibiricum had higher averages for height, chlorophyll b content, and shoot and total dry mass, as well as a greater ability to colonize the rhizosphere and roots of C. citriodora, resulting in the production of higher-quality seedlings. Inoculation of seeds of C. citriodora with endophytic bacteria proved to be a promising alternative for plant development.

Physiological quality of sunflower seeds under water stressed conditions

Water is one of the factors that most influences the seed germination process; however, its excess can cause injuries to cell membranes due to rapid imbibition. On the other hand, water restriction limits seed germination, promoting a reduction in cell water potential that disrupts physiological and metabolic reactions. Thus, the objective of this study was to evaluate the physiological quality of sunflower seeds subjected to water stress induced by polyethylene glycol 6000 (PEG 6000). The experimental design used was completely randomized, consisting of six treatments consisting of osmotic potentials (0; -0.3; -0.6; -0.9; -1.2; and -1.5 MPa) simulated with aqueous solutions of PEG 6000. Germination, radicle protrusion, first count, germination speed index, abnormal seedlings, shoot length, and root length were evaluated. Water stress induced by PEG 6000 solutions affects the physiological quality of sunflower seeds, being proportional to the reduction of osmotic potential. Germination and seed vigor decrease under water stress conditions from an osmotic potential of -0.4 MPa, with the most negative potentials (-1.2 and -1.5 MPa) preventing seed germination.

Exploring physiological variables and lipid fraction characteristics in chia nutlets: Correlations with biophysical techniques across varieties with varying germinative power and vigor

Understanding aging in seeds is vital for conservation and long-term preservation. This study examined the physiological and lipid characteristics of three chia varieties (WN, MNI, MNII) using conventional and biophysical methods to establish correlations and explore aging mechanisms. Variables assessed included thousand seed weight, moisture content (MC), and germination parameters, such as normal germination power (NGP), hypocotyl and radicle length, vigor, viability, as well as lipid characteristics, and thermal parameters. Physiological differences were prominent, especially in the MNII, with longer mean germination times (MGT = 2.11 d) and reduced NGP (63.24%). The WN variety exhibited superior germination (NGP = 95.9%), while MNI had an NGP of 93.2% and the highest vigor. Lipid analysis revealed significant differences, particularly in free fatty acid content (FFA). The oxidative status and tocopherol content were evaluated, with high germination in WN being associated with the combination of tocopherol isomers. The thermal analysis highlighted the predictive potential of ΔH for seed health and viability. Spectral analysis distinguished nutlets and oils, showcasing unique vibrational patterns. The correlation analysis revealed significant relationships crucial for conservation. MGT showed positive correlations with moisture content, electrical conductivity, and FFA, but negative correlations with germinated nutlets (GN) and normal seedlings (NS). MC positively correlated with FFA, abnormal seedlings (AS), and deteriorated nutlets, yet negatively correlated with GN and NS. Electrical conductivity emerged as a germination indicator, positively correlating with FFA and deteriorated nutlets, and negatively with GN and NS. δ-tocopherol content positively correlated with successful germination and NS, but negatively with AS. Thus, this research provides relevant knowledge on the conservation of chia nutlets by offering information on seed deterioration markers that can be obtained by FT-IR and DSC. This is particularly valuable for studying germplasm with a limited sample size, common in gene banks.

Analysis of seedling images to evaluate the physiological potential of soybean seeds

The use of artificial intelligence techniques collaborate in laboratory analysis of seeds. In this sense, the objective of this work was to verify the efficiency of the Ground Eye® equipment in evaluating the vigor of soybean seeds and the agronomic performance of soybean varieties 74I77 RSF IPRO and NT 1478SP. For this, experiments were carried out to analyze the germination of soybean seeds. The variables analyzed by the analyst and Ground Eye® equipment were the following: number of normal, intermediate, weak and abnormal seedlings. The tetrazolium, vigor and seedling emergence test under field conditions for soybean cultivars were also performed. For seedling emergence in the field, tetrazolium test and vigor there was no statistical difference between soybean cultivars. The Ground Eye Series L equipment showed a lower number of normal seedlings, number of intermediate seedlings, number of weak seedlings and a higher number of vigorous seedlings when compared to the analyzes carried out manually. Based on the results, the cultivar NT 1478SP showed better performance and may be promising in the field. The Ground Eye L Series equipment is an efficient tool for checking the vigor of soybean seedlings, helping the analyst to perform the tests more quickly.

Contribution to the Optimization of Methods for Vigor Seed Evaluation of Camelina sativa (L.) Crantz

Camelina, a traditional oil-producing plant, has gained global interest due to the high-quality oil found in its seeds. It has numerous applications, including human dietary consumption, aviation biofuel, and biodiesel production. Seed quality testing is crucial for identifying suitable seed batches for market sale. Currently, vigor tests have been established for a limited selection of commercially cultivated plant species, including camelina. This study aims to assess seed vigor and contribute to the development and validation of methods/tests for reliable vigor assessment. The experiment used two camelina genotypes developed at the Institute of Field and Vegetables Crops in Novi Sad, Serbia. The findings revealed a noteworthy reduction in germination percentages for both genotypes across all the conducted tests, as compared to the conventional laboratory germination. Simultaneously, there was a notable increase in abnormal seedlings. However, no statistically significant differences in the values of growth parameters were observed among the applied tests. In summary, the reduced seed vigor values indicate potential issues with this trait, despite generally sound germination. Additionally, the preliminary findings and methodology developed for testing the camelina seed vigor highlighted the need for optimization when applying these tests to other species to ensure their reliability and applicability.

Kvalitet semena lucerke iz različitih regiona Srbije u periodu čuvanja do 42 meseca

This study presents the findings from assessing the quality of alfalfa seeds collected from three Serbian regions: in each region, batches of seeds from six places were analyzed. The following criteria were investigated: the proportion of dormant seeds, the germinated seed content, the proportion of dead seeds, and the percentage of aberrant seedlings. Seed quality was assessed after six, eighteen, thirty, and forty-two months of storage. The highest seed quality was obtained after thirty and eighteen months of seed storage (91% and 89% of germination, respectively). During the 42-month storage period, the percentage of dead seeds (8%) and abnormal seedlings (7%) increased, while germination declined to 84%. In a storage period of six months, the participation of dormant seeds of 21% affected the germination rate, which was 77%, regardless of the low proportion of dead seeds (1%) and abnormal seedlings (2%).

Effect of treatment with thiamethoxam and cyantraniliprole on the germination and storage of forest tree seeds

ABSTRACT: Seed predation is a problem that limits the use of direct sowing of tree species, and it is necessary to develop studies involving products used in seed treatment. The objectives of this study were to evaluate the effects of treatment with insecticides on the storage and germination of seeds of six forest species. Seeds were treated with thiamethoxam and cyantraniliprole and germinated on paper and sand substrates at 25 °C under constant light. For storage, the seeds were treated and analyzed at 0, 3 and 6 months. For both tests, the following variables were evaluated: germination, mortality, hard seeds, abnormal seedlings, average length of shoot and primary root, and germination speed index (GSI). For Senna multijuga, treatment with insecticides had no effect. Peltophorum dubium and Enterolobium contortisiliquum showed positive effects of the treatments on seedling vigor and development, while Guazuma ulmifolia displayed a negative effect on primary root length. Bowdichia virgilioides and Hymenaea courbaril seeds were sensitive to the treatments. It is possible to treat and store P. dubium and E. contortisiliquum seeds with thiamethoxam for up to six months.

Assessment of Handroanthus impetiginosus (Mart. ex DC.) Mattos seed quality through X-ray testing

ABSTRACT: Several techniques are used to evaluate seed quality; however, most of them are destructive and require considerable execution time. The X-ray test has proven to be an efficient nondestructive technique for evaluating the quality of seeds. This study aimed to evaluate internal damage in ipê-roxo (Handroanthus impetiginosus) seeds through X-ray tests and to investigate how it affects seed germination. Samples from four lots of ipê-roxo seeds were exposed to radiation and, subsequently, the radiographs were analyzed using ImageJ software and the seeds divided into four classes based on their internal morphology: 1) seeds with an embryonic cavity filled with more than 50%; 2) an embryonic cavity filled up to 50%; 3) an embryonic cavity attacked by insects; and 4) an empty embryonic cavity. After that, the seeds were subjected to a germination test and, after 21 days, scored as germinated, nongerminated, dead, and normal and abnormal seedlings. The X-ray test proved to be effective in evaluating the internal morphology of ipê-roxo seeds and their relationship with physiological quality. Radiographic analysis enabled the precise identification of damage, such as embryonic malformation and damage by insects.

The allelopathic effects of aqueous Talinum triangulare (jacq.) willd extracts on the development of Lactuca sativa L. seedlings.

Plants that produce allelopathic compounds against weeds have emerged as a potential solution for the development of ecologically correct bioherbicides. Talinum triangulare is noteworthy in this regard, as its phytochemical composition encompasses flavonoids, alkaloids and other metabolites that can be used to develop inhibitory weed growth solutions. Lactuca sativa (lettuce) has been widely applied as a bioindicator species for bioherbicides and several chemicals, animal waste, water and soil quality, and atmospheric contamination, among others. In this context, this study aimed to assess the potential allelopathic effect of aqueous T. triangulare extracts on the development of L. sativa seedlings. A completely randomized design employing a 2x4 factorial scheme (shoot and root extracts) x the concentration of each extract (0, 2.5, 5, 7.5%) was applied, comprising four replications. Lactuca sativa seeds were sown on germitest papers soaked with the extracts in a germination chamber at 20°C. Physiological seed evaluations comprising the germination test, where normal and abnormal seedlings are counted on the seventh day after sowing, first normal seedling counts on the fourth day after sowing, and seedling and root length measurements. At the end of the germination test, L. sativa seedlings were separated for morphoanatomical characterizations and chlorophyll a fluorescence analyses. The T. triangulare extracts significantly influenced L. sativa root growth, with shoot extract exposure leading to more abnormal plants and lower root lengths at increasing concentrations and compared to the root extract. Root extract exposure led to evident cellular changes and lower non-photochemical quenching and unregulated dissipation quantum yields at a 5% exposure dose compared to shoot extract exposure. These findings suggest that both aqueous T. triangulare root and shoot extracts from 5% exposure doses exhibit high potential as bioherbicides, acting directly on plant structure, anatomy, quality, size and physiology.

Abordagem molecular em genitores elites de mamoeiro com foco na qualidade fisiológica das sementes

Abstract: Papaya seeds have natural barriers (phenolic compounds, seed structure and genetic factors) that make their germination difficult. And the use of seeds is the main means of propagating the species, whether for commercial cultivation, maintenance of germplasm or selection of genetic materials. Thus, the use of seeds with physiological quality (germination, normal seedlings and germination speed) is fundamental to the production of vigorous plants. However, few studies have been developed with the aim of evaluating and improving seed quality. From this perspective, the study aims to evaluate the quality of seeds in genetic materials widely used to obtain new genotypes, in order to identify superior materials and possible crosses between those that have high physiological seed quality. For this purpose, 44 genotypes were analyzed by molecular characterization, via microsatellite markers (observed and expected heterozygosity, number of alleles, information index, fixation index, inbreeding coefficient, genetic structure and genetic dissimilarity via UPGMA grouping), as well as determining physiological quality of the seed (germination speed index, percentage of germination and abnormal seedlings). Among the genotypes, 10 have germination above 60%, a high rate of germination speed and a low percentage of abnormal seedlings, and can be used in crosses to improve seed quality. The dissimilarity analysis was able to highlight the dissimilarity between the accessions of the Solo and Formosa groups. The use of the dissimilarity coefficient and the number of shared alleles made it possible to identify 18 possible crosses promising to improve the quality of papaya seeds.

Physiological quality of seeds of arabic coffee cultivars stored for a period of two years.

The rapid loss of viability, coupled with the difficulties and limitations in conserving coffee seeds, are some of the challenges that nurseries are currently facing. Thus, the objective of this work was to analyze the physiological quality of stored Arabica coffee seeds from cultivars recommended for planting in Brazilian mountainous regions. Seeds from 10 Arabica coffee cultivars were used: Catucaí-785/15, Catucaí-2SL, Catucaí-24/137, Japan, Arara, Acauã, Catuaí IAC-81, Mundo Novo IAC-379/19, Catuaí IAC-62, and Caturra IAC-479. The seeds were collected in the Arabica coffee seed production field, in the municipality of Marechal Floriano-ES. They were subsequently processed and dried in the shade, at room temperature, until reaching a humidity of 35 ± 1%, analyzed and stored in a natural laboratory environment (25 ± 2 °C), for 24 months. The following were analyzed: seed water content, germination, germination speed index, electrical conductivity and potassium leaching. The experimental design used was completely randomized, with ten cultivars, two storage times, with four replications of 25 seeds. Storing arabica coffee seeds for 24 months results in a drop in the germination percentage. Stored seeds of the Catucai 24/137 and Arara cultivars showed germination percentages similar to those of newly harvested seeds. Seeds of the Catuai IAC-62 cultivar maintain vigor during storage. The stored seeds of the Caturra IAC-476 and Japi cultivars showed a reduction in physiological quality. Electrical conductivity and potassium leaching tests are efficient in identifying seeds in an advanced state of deterioration. Seeds of Arabica coffee cultivars stored for 24 months, under the conditions of the present study, produce abnormal seedlings.

Efficacy and phytotoxicity of various thiabendazole and tebuconazole ratios in a fungicidal mordant

When developing combined preparations, a possible phytotoxic effect should be considered, depending on the dose of the mordant. Fusarium oxysporum and Pyrenophora graminea strains were cultured in a liquid enrichment culture with the addition of fungicides at a concentration of 1.5; 2.5; 3.3 ppm. Wheat grains of the Avesta variety were treated with thiabendazole and tebuconazole in the following doses: 20 g a.d./ t, 30 g a.d./t, 60 g a.d./t, 80 g a.d./t, 100 g a.d./t of grain. The effectiveness of tebuconazole and thiabendazole on mycelium growth slightly depended on their concentration. A.d. mutually reinforced each other. The synergism of the action of two a.d. is revealed. The analysis of variance showed that the effect of tebuconazole was greater than the thiabendazole effect. For both strains, the optimal ratios of tebuconazole and thiabendazole are 1.5:2.5 ppm. The addition of salicylic acid is effective at ratios of 2.5:0 and 2.5:3.3. The mixture of thiabendazole and tebuconazole reduced the germination energy of the grains mainly due to the appearance of abnormal seedlings. A composition of active substances for seed etching is proposed, including the following ratios of components, pts. wt.: tebuconazole 20-100, thiabendazole 20-150.

Genetic diversity in maize at germination and seedling stages under simulated drought conditions

Ninety seven maize (Zea mays) genotypes were evaluated for germination and early seedling characters under PEG6000 (8%) induced drought stress to identify drought tolerant genotypes. Descriptive statistics for percentage of seed germination and abnormal seedling, shoot length, root length, and shoot dry weight, root dry weight, seedling length, seedling dry weight, and vigor index revealed significant variation among the genotypes studied. The percentage of germination and abnormal seedlings varied greatly among the genotypes. The first and second principal components (PC) of PCA results accounted for 73.15 and 26.85% of the total variation of maize genotypes, respectively. The first PC variation consisted primarily of relative seedling shoot dry weight and relative seedling root dry weight. Cluster analysis grouped the genotypes into four clusters. Cluster III genotypes performed better in terms of relative shoot dry weight, relative root dry weight, and number of abnormal seedlings, indicating drought tolerance. Very poorly performance was shown by genotypes in cluster IV, whereas moderately performance was shown by genotypes in cluster II and I. The clusters differed significantly from one another, according to D2 and multivariate analysis. Thirty six genotypes viz. BD-814, BD-810, BD-812, BD-821, BD-815, BD-10015, BD-10238, CML-552, BD-822, BD-826, CML-341, CML-555, CML-591, CML-523, CML-564, BD-817, BD-10018, BD-10240, CML-577, CML-342, CML-556, BD-837, CML-544, BD-827, BD-806, BD-835, BD-840, BD-842, BD-10010, CML-562, BD-10239, BD-10016, CML-593, CML-568 and BD-10234 demonstrated relatively drought tolerance during the germination and early seedling stages might be used in future breeding program. Ann. Bangladesh Agric. (2023) 27 (2): 19-30