Germination Of Corn Research Articles

Effects of Italian ryegrass desiccation timing on corn performance: is growth inhibition due to the release of plant allelochemicals or nitrogen immobilization?

Context There is no consensus between farmers and researchers about timing for ryegrass desiccation before corn sowing, considering interactions between ryegrass straw, nitrogen immobilization, and allelochemical release impacting corn growth. Aims This study aims to assess the effects of different desiccation timings of annual ryegrass (Lolium multiflorum Lam.) and nitrogen management on corn. We sought to elucidate whether corn growth inhibition is attributable to allelochemical release or nitrogen immobilization. Methods A two-year field factorial experiment was conducted, with Factor A comprising fallow and three ryegrass desiccation timings before corn sowing, and Factor B involving two nitrogen fertilization methods to evaluate N immobilization. Laboratory experiments assessed allelopathic properties using a 3 (desiccation periods) × 5 (ryegrass extract concentrations) factorial design. Assessments included corn (Zea mays) germination, seedling radicle and coleoptile length, and germination speed. Results Ryegrass desiccation timing of less than 20 days before corn sowing reduced corn stature at the beginning of development and grain yield, due to nitrogen immobilization and allelopathic influences possibly exercised by caffeic acid and epicatechin present in roots and shoots, released as residues decomposed. Non-desiccated ryegrass aqueous extracts reduced germination speed and germinability. Root/shoot extracts reduced seedling elongation. Desiccated aqueous extracts at 15 and 30 days before corn sowing didn’t present inhibitory effects. Conclusion Nitrogen enhances corn growth regardless of ryegrass influence, under these experimental conditions. Ryegrass desiccation timing affects corn yield; and delaying corn sowing post-desiccation mitigates losses. Ryegrass extracts inhibit corn germination and viability, regardless of concentration, possibly due to phytotoxic compounds.

Optimization of Sargassum bovianum Extraction Techniques for Germination of Wheat, Canola, and Corn Under Different Salinity Stress

Seaweeds are a cheap, eco-friendly, and rich source of plant growth stimulators that can mitigate the adverse effects of salinity stress. This study examined the impact of Sargassum bovianum extracts obtained through different techniques using pressure, heat, and microwave radiations on the germination and growth of wheat, corn, and canola seeds under varying salinity levels (500, 3500, and 6500 µS cm−1). The findings showed that pressure, microwave, and acidic extraction methods were the most effective in extracting polysaccharides, alginate, and nutrients from S. bovianum. Seaweed extract significantly improved the mean germination time (MGT) and germination index (GI) of wheat under high salinity stress and had a positive effect on wheat plumule length (PL) and germination percentage (GP). However, seaweed extract had no significant impact on canola seeds in salinity stress, except for improved canola PL. The PL and seedling vigor index (SVI) of corn were enhanced in low salinity levels, but most treatments reduced PL and SVI in high salinity. This study suggests that using heat, pressure, and microwave techniques for seaweed extraction results in higher polysaccharides and alginate content, leading to improved germination and plant growth, particularly in wheat and canola. These findings can help growers optimize the germination and growth of these important crops.

Hydrolysates from cauliflower and artichoke industrial wastes as biostimulants on seed germination and seedling growth: a chemical and biological characterization.

Cauliflower (Brassica oleracea L.) and globe artichoke (Cynara scolymus L.) are vegetables with a high waste index mainly related to stems and leaves. In this study, enzymatic hydrolysates obtained from these wastes were proposed to be used as plant biostimulants. Life cycle assessment methodology was also applied to evaluate environmental performances related to cauliflower and artichoke byproducts. Hydrolysates (HYs) were chemically and biologically characterized. Amino acids, organic acids, amines, polyols, mineral elements, phenols, tannins, flavonoids and sulfur compounds were identified and quantified by means of NMR, inductively coupled plasma mass spectrometry and UV-visible analyses. Cauliflower leaf and flower HYs showed the highest concentration of free amino acids, whereas stems showed the highest concentration of Ca. Regarding artichoke, asparagine, glutamine and aspartic acid were exclusively detected in stems, whereas artichoke leaves showed the highest Mg and Mn levels together with the highest antioxidant activity. The HYs diluted in water were tested as biostimulants. The impacts of five concentrations of HYs (0.00, 0.28, 0.84, 2.52 and 7.56 g L-1) on seed germination and early seedling growth of crimson clover, alfalfa, durum wheat and corn were investigated. The application of artichoke biostimulant (0.28 g L-1) positively influenced the coefficient of velocity of germination in alfalfa, crimson clover and durum wheat, whereas cauliflower biostimulant significantly improved corn germination speed. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Sweet corn association panel and genome-wide association analysis reveal loci for chilling-tolerant germination

Sweet corn is highly susceptible to the deleterious effects of low temperatures during the initial stages of growth and development. Employing a 56K chip, high-throughput single-nucleotide polymorphism (SNP) sequencing was conducted on 100 sweet corn inbred lines. Subsequently, six germination indicators—germination rate, germination index, germination time, relative germination rate, relative germination index, and relative germination time—were utilized for genome-wide association analysis. Candidate genes were identified via comparative analysis of homologous genes in Arabidopsis and rice, and their functions were validated using quantitative real-time polymerase chain reaction (qRT-PCR). The results revealed 35,430 high-quality SNPs, 16 of which were significantly correlated. Within 50 kb upstream and downstream of the identified SNPs, 46 associated genes were identified, of which six were confirmed as candidate genes. Their expression patterns indicated that Zm11ΒHSDL5 and Zm2OGO likely play negative and positive regulatory roles, respectively, in the low-temperature germination of sweet corn. Thus, we determined that these two genes are responsible for regulating the low-temperature germination of sweet corn. This study contributes valuable theoretical support for improving sweet corn breeding and may aid in the creation of specific germplasm resources geared toward enhancing low-temperature tolerance in sweet corn.

Wavelength selection method for near-infrared spectroscopy based on Max-Relevance Min-Redundancy

Near-infrared spectroscopy (NIRS) is a rapid, nondestructive analytical technique utilized in various fields. However, the NIR data, which consists of hundreds of dimensions, may exhibit considerable duplication in the spectrum information. This redundancy might impair modeling effectiveness. As a result, feature selection on the spectral data becomes critical. The Max-Relevance Min-Redundancy (mRMR) method stands out among the different feature selection techniques for dimensional reduction. The approach depends on mutual information (MI) between random variables as the basis for feature selection and is unaffected by modeling methods. However, it is necessary to clarify the benefits of the maximum correlation minimal redundancy algorithm in the context of near-infrared spectral feature selection, as well as its adaptability to various modeling methods. This research focuses on the NIR spectral dataset of maize germination rate, and the mRMR method is utilized to select spectral features. Based on the preceding foundation, we create models for Support Vector Regression, Gaussian Process Regression, Random Forest, and Neural Networks. The experimental findings demonstrate that, among the feature selection methods employed in this paper, the Max-Relevance Min-Redundancy algorithm outperforms others regarding the corn germination rate dataset.

Germination and growth of corn submitted to sowing and cultivation management by subsurface drip irrigation in the North China Plain

Germination and growth of corn submitted to sowing and cultivation management by subsurface drip irrigation in the North China Plain

Potential of yeasts as biocontrol agents against Fusarium graminearum in vitro and on corn.

The antifungal effect of the yeast species Kluyveromyces marxianus, Meyerozyma caribbica, and Wickerhamomyces anomalus was evaluated against two Fusarium graminearum strains (FRS 26 and FSP 27) in vitro and on corn seeds. The antifungal effect of the yeasts against F. graminearum was evaluated using scanning electron microscopy and extracellular chitinase and glucanase production to further elucidate the biocontrol mode of action. In addition, the germination percentage and vigor test were investigated after applying yeast on corn seeds. All the yeast strains inhibited fungal growth in vitro (57.4%-100.0%) and on corn seeds (18.9%-87.2%). In co-culture with antagonistic yeasts, F. graminearum showed collapsed hyphae and turgidity loss, which could be related to the ability of yeasts to produce chitinases and glucanases. The three yeasts did not affect the seed corn germination, and W. anomalus and M. caribbica increased corn seed growth parameters (germination percentage, shoot and root length, and shoot dry weight). Meyerozyma caribbica and W. anomalus showed satisfactory F. graminearum growth inhibition rates and did not affect seed growth parameters. Further studies are required to evaluate the application of these yeasts to the crop in the field.

Effect of Modified Biochar Prepared by Co-pyrolysis of MgO on Phosphate Adsorption Performance and Seed Germination.

Biochar is currently used as a phosphate adsorbent in water and subsequently as a soil amendment. In this study, modified biochar was prepared directly by co-pyrolysis of MgO and rice straw, and a preliminary ecotoxicological assessment was performed before the application of modified biochar to soil. The effects of single factors, such as pyrolysis temperature, dosage, pH, and coexisting ions, on phosphate adsorption performance were investigated. In addition, after phosphate adsorption, the effects of modified biochar leachate on the germination of corn and rice seeds were examined. The results showed that phosphate adsorption by the modified biochar first increased and then decreased as the pyrolysis temperature increased, with modified biochar prepared at 800 °C showing the greatest adsorption. In addition, a comprehensive cost analysis showed that the best phosphate adsorption effect of modified biochar was achieved at a dosage of 0.10 g and a solution pH of 3. In contrast, the presence of competitive coexisting ions, Cl- , NO3 - , CO3 2- , and SO4 2- , reduced the phosphate adsorption capacity of the modified biochar. The adsorption kinetics results revealed that the process of phosphate adsorption by the modified biochar was more in line with the pseudo-second-order model and dominated by chemisorption. Moreover, the adsorption isotherm results indicated that the process was more in line with the Langmuir model and dominated by monomolecular layer adsorption, with a maximum adsorption of 217.54 mg/g. Subsequent seed germination tests showed that phosphate-adsorbed modified biochar leachate had no significant effect on the germination rate of corn seeds, whereas it improved the germination rate of rice seeds. Together, these results provide guidance for the application of modified biochar firstly as an adsorbent of phosphate and subsequently as a soil remediator.

Landscape position and cover crops affects crop yields in a terrace-tiled field

Cover crops (CC) provide soil ecosystem benefits including reduced soil erosion, improved soil health, and nutrient cycling. However, the effect of CCs on rotational commodity crop grain yields and nutrient uptake may vary at different landscape positions and under different soil moisture dynamics. The objectives of this study were to determine the influence of CCs in a terraced field on soil moisture at crop emergence and reproductive stages of corn (Zea mays L) and soybean (Glycine max L. Merr.) development, and evaluate CCmix (wheat (Triticum aestivum L.), radish (Raphanus raphanistrum subsp. Sativus), and turnip (Brassica rapa subsp. Rapa)) and cereal rye (Secale cereale L.) effect on corn and soybean grain yield and plant nutrient concentration, respectively. A randomized complete block design with two treatments including cover crop (CC) and no cover crop (no CC) and three replications was used. In this 4-year study, cereal rye produced 1.0–1.6 Mg ha−1 higher aboveground biomass compared to the CCmix species. Nutrient uptake in the CCmix biomass was greater than cereal rye. Soybean yield following cereal rye termination was not influenced by the CC treatment (P = 0.3229). Dry climatic conditions during the soybean growing period and landscape positions influenced grain yield and nutrient uptake. Average soybean yield at different landscape positions was ranked as shoulder (4.8 Mg ha−1) > backslope (4.4 Mg ha−1) > footslope (3.9 Mg ha−1) > channel (3.6 Mg ha−1). In 2021, corn yield was reduced 29% following the CCmix compared to no CC control, indicating a yield penalty when corn was preceded with the CCmix species. In this study, higher CC biomass production exacerbated soil wetness in a wet year (2021), resulting in uneven corn germination and excess soil water stress on plant growth. Increased soil wetness at channel and footslope positions in 2019 and 2021 reduced corn yield 45–70%. This study suggests that CCs in terraced fields can have a neutral or negative effect on the following commodity crop yield depending on the weather conditions.

Viabilitas Benih Jagung Lokal (Zea mays L.) Kabupaten Timor Tengah Utara Yang Diberi Perlakuan Kolkisin

Background: Colchicine is a chemical mutagen that has been widely used to increase the viability of a plant. Most of the people of the North Central Timor (TTU) Regency still depend on local agricultural products, so one of the crops cultivated during the rainy season is local corn. This study aimed to determine the viability of local maize seeds in North Central Timor Regency and the appropriate concentration of colchicine to increase local maize germination. Methods: used in this research is an experimental method that gives colchicine treatment to 3 local corn varieties. The colchicine used was 0% (control), 40%, and 60%. The viability parameters observed were maximum growth potential (PTM), germination capacity (DB), and vigor index (IV). Results: showed that there were variations in the measurement of viability parameters observed both at maximum growth potential (PTM JBa 16,6%, JBu 35%, JKa 10%, JKu 8,33%), germination (DB 70%, JBu 81,66%, JKa 60%, JKu 61,66%) and vigor index (IV 68,33%, JBu 78,33%, JKa 63,33%, JKu 68,33%). Conclusions: the appropriate concentrations of colchicine to increase local corn germination were 40% and 60%, respectively. This can be seen in the viability parameters that show differences, namely the maximum growth potential (PTM) of flower corn with a colchicine concentration of 40%, which is 35%, the germination capacity (DB) of flower corn with a colchicine concentration of 60%, which is 90%, and the vigor index (IV) of flower corn. The concentration of colchicine 60% is 90%.

Integrated metabolomics and transcriptomics analysis during seed germination of waxy corn under low temperature stress

BackgroundWaxy corn has a short growth cycle and high multiple cropping index. However, after being planted in early spring, late autumn and winter, it is susceptible to low temperature (LT), which reduces the emergence rate and yield. Therefore, it is important to analyze the response mechanism of waxy corn under LT stress.ResultsAll phenotype indexes of waxy corn inbred lines N28 were significantly higher than waxy corn inbred lines N67 under LT. With the increase of LT stress time, all physiological indexes showed an upward trend in N28 and N67. Differentially expressed genes (DEGs) 16,017 and 14,435 were identified in N28 and N67 compared with nongerminated control under LT germination, respectively, and differential metabolites 127 and 93 were detected in N28 and N67, respectively. In addition, the expression level of some genes involved in plant hormones and mitogen activated protein kinase (MAPK) signaling pathways was significantly up-regulated in N28. Compared with N67, flavonoid metabolites were also significantly enriched in N28 under LT germination.ConclusionUnder LT stress, the inbred lines N28 was significantly higher than the inbred lines N67 in the phenotypic and physiological indices of cold resistance. Compared with N67, the expression levels of some genes involved in the plant hormones and MAPK pathways were significantly up-regulated in N28, and flavonoid metabolites were also significantly enriched in N28 under LT stress. These genes and metabolites may help N28 to improve cold resistance and may be as potential target genes for cold resistance breeding in waxy corn.

Germination and Seedling Growth Rate of Corn (Zea mays L.) on Different Soil Media

Germination and Seedling Growth Rate of Corn (Zea mays L.) on Different Soil Media

Allelochemical of Archidendron jiringa Pods and Sorghum bicolor Biomass Extracts Combined with a Premixed Formulation of Atrazine and Mesotrione

The aim of this research was to evaluate the allelochemicals in jering pods and sorghum biomass extracts combined with premixed formulations of the herbicides, atrazine and mesotrione. The research was conducted in the laboratory and experimental field of the Department of Agronomy, University of Bengkulu, Indonesia, from December 2019 to July 2020. The allelochemicals in jering pods and sorghum biomass extracts and their combination with the herbicides were tested on seed germination, and weed control was tested on corn grown in polybags. The results showed that aqueous extracts of jering pods and sorghum biomass combined with the herbicide mixtures of atrazine and mesotrione did not inhibit the seed germination of corn but suppressed the length and the weight of the radicles and plumules. The study of the efficacy of jering pods and sorghum biomass extracts on the weeds (total of grasses and broadleaves) revealed that the two agents, when applied separately, suppressed weed biomass by 27 and 32%, respectively. When the two extracts were combined, their combined efficacy increased to 56%. Furthermore, the plant height, stem diameter, and corn stover weight increased with the allelochemicals and herbicide treatments. The cobs yield per plant increased from 19 to 22% with the separate application of the allelochemicals found in the jering pods and sorghum biomass, respectively, and from 27 to 34% when the allelochemicals were combined with the herbicides. This research provided a novel approach using the allelochemical extracts from jering pods and sorghum biomass as natural herbicides for weed control.

Bidens pilosa as potential biofungicide against postharvest pathogens on two agroforestry cash crops

An in vivo experiment was conducted at the College of Agriculture, CMU, Musuan, Bukidnon, Philippines on corn and peanut seeds in order to assess the antifungal effects of the different concentrations of powdered Bidens pilosa leaves against postharvest pathogens. B. pilosa powder was thoroughly mixed at varying amounts as treatments to corn and peanut seeds and observed for the presence of fungal growths during the observation period of up to 35 days. Data gathering revealed the occurrence of 5 fungal species namely Aspergillus flavus, A. niger, Fusarium sp., Rhizopus sp., and M. phaseolina. The best antifungal treatment is the chemical fungicide Captan, however, T5 (30 g of B. pilosa/kilo of seeds) shows the potential to inhibit the growth of A. flavus, Rhizopus sp., and A. niger in corn while T4 (20 g of B. pilosa/kilo of seeds) had the potential to inhibit or prevent the growth of the two Aspergillus spp. in peanut. It was also noted that for corn, the least fungal count with a value of 1.00 was noted in T5 (30 g of B. pilosa/kilo of seeds) while for peanut, T4 (20 g of B. pilosa/kilo of seeds) had the potential to limit the growth of pathogenic fungi with a fungal count value of 1.33. The application of B. pilosa did not affect significantly the percentage germination of corn but with peanut, T5 (30 g of B. pilosa/kilo of seeds) shows a promising performance. On Seedling Vigor Index (SVI), the application of B. pilosa did not significantly influence the SVI of corn but for peanut, T5 (30 g of B. pilosa/kilo of seeds) has shown potential as it shows a better performance as compared with the other treatments. In this research, B. pilosa exhibited its potential as a biofungicide.

Lactobacillus helveticus EL2006H cell-free supernatant enhances growth variables in Zea mays (maize), Glycine max L. Merill (soybean) and Solanum tuberosum (potato) exposed to NaCl stress.

Plant growth promoting microorganisms and their derived compounds, such as cell-free supernatant (CFS), enhance plant growth under stressed and non stressed conditions. Such technology is sustainable and environmentally friendly, which is desirable amidst the climate change threat. The current study evaluated the effect of CFS obtained from Lactobacillus helveticus EL2006H on its ability to enhance mean percentage germination and mean radicle length of corn and soybean, as well as growth parameters of potato, using treatment formulations that consisted of 0.2 and 1.0% [v/v] L. helveticus EL2006H CFS concentrations and 100 mM NaCl and 150 mM NaCl levels. Results show that treatment with 100 mM NaCl lowered percentage germination of corn by 52.63%, at 72 h, and soybean by 50%, at 48 h. Treatment with 100 NaCl +0.2% EL2006H enhanced percentage germination of soybean by 44.37%, at 48 h, in comparison to that of the 100 mM NaCl control. One hundred mM NaCl lowered radicle length of corn and soybean by 38.58 and 36.43%, respectively. Treatment with 100 Mm NaCl +1.0% EL2006H significantly increased radicle length of corn by 23.04%. Treatment with 100 mM NaCl +0.2% EL2006H significantly increased photosynthetic rate, leaf greenness and fresh weight of potato. Increasing NaCl concentration to 150 NaCl lowered the effectiveness of the 0.2% EL2006H CFS on the same growth variables of potato. In general, the lower CFS concentration of 0.2% was more efficient at enhancing germination in soybean while the higher concentration of 1.0% was more efficient at enhancing radicle length of corn. There was an observed variation in the effectiveness of L. helveticus EL2006H CFS across the different CFS concentrations, NaCl levels and crop species studied. In conclusion, based on findings of this study, CFS obtained from L. helveticus can be used as a bio stimulant to enhance growth of corn, soybean and potato. However, further studies need to be conducted, for validation, especially under field conditions, for commercial application.

Experimental explore of the impact of MF 9108 VE planter settings on corn yield

The explore is devoted to the impact of row unit down force, planting depth, planting rate, singulation and planting velocity on corn germination and yield. Planting depth is crucial for technological operations of planting corn. The explore of planting corn seeds at a depth of 2.5 cm, 5.1 cm, 7.6 cm and 10,1 were fulfilled using the MF 9108 VE planter. Down force on planter row unit is also significant at planting operation. Inadequate down force conduct to deprivation of planting depth, planting of seeds in soil with low humidity and deprivation of the yield. Planting with superfluous down force on the row unit, conduct to compaction of the root zone for plants and as a result the crop deprivation. The planting explores of down force on the row unit have been made with help of Delta Force system from Precision Planting company. The equipment has been regulated to the pressing mode 200 kg, 20 kg, automatic mode (the contact force of the row unit depth wheels with soil at level 50 kg). Doubles and skips also have impact on yield of corn. Therefore, explore of singulation is extremely significant. If we have the doubles, we will have battle between plants, stress for them and a great decline of the yield. If we have skips, we will have the planting rate decline, reducing of corn kernels quantity in the row, and yields reduction. The explores of corn planting have been made with singulation 93.5 % and the control plot with a singulation 99. 5%. The explores of impact of planting velocity 8 and 16 km/h on quality of planting and corn yield have been made. The explores of impact of planting rate 70 000 seeds/ha and 80 000 seeds/ha on corn yield have been made. According to results of MASSEY FERGUSON MF 9108 VE planter with Delta Force and SpeedTube system study, the following operating adjustments could be recommended: plating depth – 5 cm, panting velocity – 16 km/h, Delta Force in automatic setting with depth wheel force to the soil 50 kg, 99.5 % level of singulation. Such modes of the planter allows to raise yield up to 2.06 t/ha. Keywords: down force, planting velocity, Delta Force, planting depth, planting rate, singulation, corn yield.

Aged sweet corn (Zea mays L. saccharata Sturt) seeds trigger hormone and defense signaling during germination

Abstract: Seed ageing during storage or shipping can affect the yield and cost of agricultural production. Sweet corn is a naturally mutated corn cultivar with weak seed vitality during storage. In this study, we have shown that endogenous hormone level dynamics of fresh and aged sweet corn seeds were different during early geminating process. Transcriptomic assembling uncovered several novel transcripts during early stage of sweet corn germination in signal transduction and RNA processing pathways. Comparative transcriptomic profiling revealed that expression of many genes was activated earlier in aged seeds than fresh ones. Functional analyses showed that, as two major networks, plant hormone signaling and defense pathways were different between fresh and aged sweet corn seeds. Auxin, cytokinin, gibberellin, salicylic acid and jasmonic acid signaling pathways were activated earlier in aged seeds than fresh ones on the first day after imbibition. These results provided knowledge for understanding the ageing process of sweet corn seeds and several candidate genes for genetic study of seed ageing mechanism.

The Effect of Nanofertilizer in Grain Corn Germination and Growth Rate

The Effect of Nanofertilizer in Grain Corn Germination and Growth Rate

Transcriptome Analysis Identifies Novel Genes Associated with Low-Temperature Seed Germination in Sweet Corn.

Typically, sweet corn, particularly sh2 sweet corn, has low seed vigor owing to its high sugar and low starch content, which is a major problem in sweet corn production, particularly at low temperatures. There is considerable variation in the germination rates among sweet corn varieties under low-temperature conditions, and the underlying mechanisms behind this phenomenon remain unclear. In this study, we screened two inbred sweet corn lines (tolerant line L282 and sensitive line L693) differing in their low-temperature germination rates; while no difference was observed in their germination rates at normal temperatures. To identify the specifically induced genes influencing the germination capacity of sweet corn at low temperatures, a transcriptome analysis of the two lines was conducted at both normal and low temperatures. Compared to the lines at a normal temperature, 3926 and 1404 differently expressed genes (DEGs) were identified from L282 and L693, respectively, under low-temperature conditions. Of them, 830 DEGs were common DEGs (cDEGs) that were identified from both L282 and L693, which were majorly enriched in terms of microtubule-based processes, histone H3-K9 modification, single-organism cellular processes, and carbohydrate metabolic processes. In addition, 3096 special DEGs (sDEGs), with 2199 upregulated and 897 downregulated, were detected in the tolerant line L282, but not in the sensitive line L693. These sDEGs were primarily related to plasma membranes and oxygen-containing compounds. Furthermore, electric conductivity measurements demonstrated that the membrane of L282 experienced less damage, which is consistent with its strong tolerance at low temperatures. These results expand our understanding of the complex mechanisms involved in the cold germination of sweet corn and provide a set of candidate genes for further genetic analysis.

Inhibitory Effect of Oregano and Laurel Essential Oils and Their Main Com-ponents on Seed Germination of Some Weed and Crop Species

The essential oils from oregano (Origanum syriacum L.) and laurel (Laurus nobilis L.), and their main components, namely, carvacrol, 1,8-cineole and α-pinene, were tested to determine their inhibitory effects on the seed germinations of three different weeds [redroot amaranth (Amaranthus retroflexus L.), wild licorice (Glycyrrhiza glabra L.), curled dock (Rumex crispus L.) and cutleaf ground-cherry (Physalis angulata L.)] and three crops [(wheat (Triticum aestivum L.), corn (Zea mays L.) and cotton (Gossypium hirsitum L.)]. Gas chromatography/mass spectroscopy (GC-MS) analysis showed that 1,8-cineole and carvacrol were the major components of laurel and oregano essential oils, respectively. An in-vitro bioassay seed germination test showed that oregano essential oil and carvacrol completely inhibited the germination of weeds at all the concentrations ranging from 1 to 5 µl/Petri dish, while seed germination of test weeds significantly decreased with increasing of the concentrations of laurel essential oil and its main components, 1,8-cineol and α-pinene ranging from 5 to 20 µl/Petri dish. Oregano essential oil and carvacrol were totally ineffective on cotton and corn germination (except for the concentration of 5 µl/Petri dish of cavracrol), whereas they had a strong inhibitory activity against wheat seeds. On the other hand, the laurel essential oil and its main component, 1,8-cineole, showed less selective action on test crop species. It could be concluded that volatile oil from O. syriacum and its main component, cavracrol, possessed a strong inhibitory effect on germination of the weeds and was totally selective action on some crops, and could be utilized as bioherbicide for future weed management programmes.