Search Results (67)

Salinity poses a significant challenge in modern agriculture, often inhibiting growth and yield, especially in sensitive crops like onions (Allium cepa L.). This study evaluated the effectiveness of a freshwater-algae-based biostimulant on two onion cultivars, Franciscana IPA-10 and Vale Ouro IPA-11, to mitigate saline irrigation’s adverse effects. Five biostimulant concentrations (0, 1, 2, 3, and 4 mL L⁻¹, applied to the soil) were tested, along with two foliar treatments at 2 mL L⁻¹ as controls. Our findings showed that applying 4 mL L⁻¹ to the soil boosted growth rates to 1.0 cm per day (1), increased the potassium-to-sodium ratio in bulbs, and improved both average bulb weight by 25.11% and overall productivity by 24.28%, relative to untreated conditions. These results suggest that the biostimulant at 4 mL L⁻¹ is an effective method to enhance resilience to saline stress and increase productivity in the IPA-10 and IPA-11 cultivars. However, while the biostimulant improved plant performance, it did not counteract the accumulation of salts in the soil. Therefore, additional management practices such as leaching and drainage are recommended to ensure sustainable onion production under saline water irrigation. Full article

Biostimulants play an active role in sustainable crop production. While biostimulants are thought to have long-term effects on plant growth, little research has been conducted to confirm this hypothesis. In this study, we investigated the long-term residual effects of biostimulants applied exclusively during the onion seedling stage on subsequent plant growth. Three onion cultivars (‘Carta Blanca’, ‘Don Victoro’, and ‘Sofire’) were evaluated with the application of nine microbial biostimulants (LALRISE Mycorrhizae, LALRISE Bacillus velezensis, Mighty Mycorrhizae, MycoApply, Spectrum, Spectrum DS, Spectrum Myco, Tribus Original, and Tribus Continuum), one seaweed extract (Kelpak), and two fertilizer types (conventional and organic fertilizer). Plant morphology and biomass were investigated during the early bulb stage of onion growth. Parameters such as plant height, neck diameter, bulb diameter, and the fresh and dry weights of the shoot, bulb, and root were measured. The results indicated significant cultivar-specific effects of microbial biostimulant and fertilizer type, as well as their interactions, on onion early bulb growth. While seaweed extract exhibited minimal residual impact, specific microbial biostimulants, such as Mighty Mycorrhizae and MycoApply, significantly enhanced bulb growth in the red onion ‘Sofire’. Tribus Continuum was found to increase bulb growth of the yellow onion ‘Don Victoro’. Positive effects of microbial biostimulants on onion growth were also observed with LALRISE Bacillus velezensis, Spectrum Myco, Spectrum, and LALRISE Mycorrizae. Furthermore, microbial biostimulants demonstrated more significant positive effects on onion growth when applied in conjunction with organic fertilizer. In conclusion, microbial biostimulants exhibited long-term positive effects on onion plant growth even when applied solely during the seedling stage prior to transplanting. However, these effects were significantly influenced by onion cultivar and fertilizer type, with the greatest benefits observed when combined with organic fertilizer. We recommend MycoApply and Mighty Mycorrhizae for growers seeking to enhance onion productivity, particularly in organic cultivation, as the two products enhanced bulb and leaf growth in ‘Sofire’ and ‘Don Victoro’. Full article

Background: The dark green coloration of bunching onion leaf blades is a key determinant of market value, nutritional quality, and visual appeal. This trait is regulated by a complex network of pigment interactions, which not only determine coloration but also serve as critical indicators of plant growth dynamics and stress responses. This study aimed to elucidate the mechanisms regulating the dark green trait and develop a predictive model for accurately assessing pigment composition. These advancements enable the efficient selection of dark green varieties and facilitate the establishment of optimal growth environments through plant growth monitoring. Methods: Seven varieties and lines of heat-tolerant bunching onions were analyzed, including two commercial ${\mathrm{F}}_1$ cultivars, along with two purebred varieties and three ${\mathrm{F}}_1$ hybrid lines bred in Yamaguchi Prefecture. The analysis was conducted on visible spectral reflectance data (400–700 nm at 20 nm intervals) and pigment compounds (chlorophyll a, chlorophyll b and pheophytin a, lutein, and $\beta$-carotene), whereas primary and secondary metabolites were assessed by using widely targeted metabolomics. In addition, a random forest regression model was constructed by using spectral reflectance data and pigment compound contents. Results: Principal component analysis based on spectral reflectance data and the comparative profiling of 186 metabolites revealed characteristic metabolite accumulation associated with each green color pattern. The “green” group showed greater accumulation of sugars, the “gray green” group was characterized by the accumulation of phenolic compounds, and the “dark green” group exhibited accumulation of cyanidins. These metabolites are suggested to accumulate in response to environmental stress, and these differences are likely to influence green coloration traits. Furthermore, among the regression models for estimating pigment compound contents, the one for chlorophyll a content achieved high accuracy, with an $R^2$ value of 0.88 in the test dataset and 0.78 in Leave-One-Out Cross-Validation, demonstrating its potential for practical application in trait evaluation. However, since the regression model developed in this study is based on data obtained from greenhouse conditions, it is necessary to incorporate field trial results and reconstruct the model to enhance its adaptability. Conclusions: This study revealed that cyanidin is involved in the characteristics of dark green varieties. Additionally, it was demonstrated that chlorophyll a can be predicted using visible spectral reflectance. These findings suggest the potential for developing markers for the dark green trait, selecting high-pigment-accumulating varieties, and facilitating the simple real-time diagnosis of plant growth conditions and stress status, thereby enabling the establishment of optimal environmental conditions. Future studies will aim to elucidate the genetic factors regulating pigment accumulation, facilitating the breeding of dark green varieties with enhanced coloration traits for summer cultivation. Full article

The noticeable reduction in plant species abundance near industrial hemp (Cannabis sativa L.) highlights the need to investigate its potential allelopathic effects on selected cultivars’ seed germination and seedling growth. Industrial hemp of the “Helena” variety was used to obtain aqueous extracts by conventional (macerate, hydrolate, and post-distillation residue) and green methods (ultrasonic and microwave extracts) in order to treat thirteen most commonly cultivated plant species, including lettuce, kohlrabi, onion, tomato, carrot, pepper, savoy cabbage, rocket, alfalfa, white mustard, pea, sunflower, and parsley. This is the first time that the allelopathic effects of seven different hemp extracts were tested simultaneously on thirteen different species. The extracts were applied at 10, 25, 50, and 100% concentrations. The seed germination percentage and root/shoot length results for all tested plants, except peas, clearly demonstrated an inhibitory effect of higher concentrations of hemp extracts. This effect was observed regardless of variations in chemical composition (CBD, THC, and total polyphenols), suggesting that different extracts have varying impacts on different species. The weakest inhibitory effect on the germination and seedling length for the majority of the tested plant species was noted for PDR, while the strongest inhibitory effect in terms of seedling length was observed in the case of MAE700. Full article

This study provides a comprehensive analysis of the composition of onion peels, tomato peels, and pistachio green hulls, with a focus on their structural and bioactive compounds. Onion peels, regardless of cultivar, were found to be rich in quercetin and its derivatives, along with other flavonoids and pectin. Tomato peels emerged as a notable source of naringenin (0.52 mg/g in ethanol extract) and rutin (0.24 mg/g in water extract) and showed an unexpectedly high lignin content, comprising nearly 50% of their structural components. Pistachio green hulls demonstrated a high extractive content (63.4 g/100 g), 73% of which were water-soluble. Protocatechuic acid, rutin, and quercetin derivatives were the dominant phenolic compounds in the water extract, while luteolin was most abundant in the ethanol extract. Regarding structural composition, tomato peels and pistachio green hulls shared similarities, exhibiting a high lignin content (53.4% and 33.8%, respectively) and uronic acids (10–15%). In contrast, onion peels were characterized by high levels of glucans (around 38%) and galacturonic acid (33%). The insights from this study pave the way for the design of sustainable and efficient extraction processes, enabling the sequential recovery of valuable bioactive compounds and promoting the valorization of these agro-industrial by-products. Additionally, onion and tomato peels were evaluated as sources of pectin using two extraction methods: conventional acid water extraction and subcritical water extraction. The results revealed significant differences in the pectin composition (53–68% galacturonic acid) and degree of esterification (79–92%) compared to commercial pectin (72.8% galacturonic acid and 68% esterification), highlighting the influence of the raw material and extraction method on the final properties of pectin. Full article

Onion cultivation in South Korea faces a range of interconnected challenges, shaped by fluctuating supply and demand dynamics, the dominance of imported seed varieties, and the growing issue of fungal pathogens affecting stored onions. In recent years, significant shifts occurred within the onion industry, such as export volumes in 2023 declining to 106 tons compared to 99,506 tons in 2022, while import volumes surged to 113,902 tons to meet domestic demand through the Tariff Rate Quota (TRQ) system. Concurrently, domestic production onion supply in 2023 estimates a total of 1.347 million tons, a 5.2% increase compared to the previous year, due to a 6.3% rise in domestic production. Despite this growth, South Korea’s onion seed market remains heavily dependent on imports, particularly from Japan, underscoring the need for the development of competitive domestic cultivars. Furthermore, environmental conditions such as microclimates in regions like Muan have proven to be critical, as they produce onions with superior nutritional profiles and storability. However, fungal diseases pose persistent threats to storage, resulting in substantial economic losses. However, the country’s reliance on imported varieties and the climate’s effects on cultivation call for more investment in domestic breeding programs and adaptive farming practices. To address these challenges, this review synthesizes historical data, current trends, and the future prospects of onion production, supply, and demand in South Korea. Comprehensive strategies are proposed, including the promotion of adaptive farming practices, investment in domestic breeding programs, and enhanced storage techniques to mitigate fungal pathogens. This work emphasizes the importance of integrated efforts among policymakers, researchers, and industry stakeholders to improve productivity, reduce reliance on imports, and secure a sustainable future for the South Korean onion industry. The findings offer actionable insights for enhancing market competitiveness and achieving agricultural sustainability. Full article

Increasing interest is being devoted to environmentally friendly strategies, such as the use of plant biostimulants, to enhance crop performance and concurrently ensure food security under the perspective of sustainable management. The effects of two biostimulant formulations (protein hydrolysate and spirulina) on four Italian traditional storage onion cultivars (Ramata di Montoro, Rossa di Tropea, Rocca Bruna, Dorata di Parma) were investigated in Naples province (southern Italy), in terms of yield, quality, shelf-life, bioactive compounds, and mineral composition. Ramata di Montoro showed the highest levels of yield (66.4 t ha⁻¹) and vitamin C (31.5 mg g⁻¹ d.w.) and the longest shelf-life (228 days). Significant increases in marketable yield were recorded under the applications of both protein hydrolysate (+15.5%) and spirulina (+12.4%) compared to the untreated control. The two biostimulant formulations significantly increased bulb shelf-life and the contents of polyphenols (201.4 mg gallic acid eq. 100 g⁻¹ d.w. on average vs. 158.6 of the untreated control), vitamin C (26.8 mg g⁻¹ d.w. on average vs. 22), and both lipophilic and hydrophilic antioxidant activities. These findings demonstrate the effectiveness of both protein hydrolysate and spirulina as sustainable tools for enhancing both yield and quality parameters within the frame of environmentally friendly farming management. Full article

Early sprouting is a main cause of onion spoilage during storage. However, limited knowledge is available on which factors trigger sprouting. Here, this was studied in the Hyfive and Exhibition cultivars, which largely differ in sprouting time. Sprouting progress was compared to the fructan and abscisic acid (ABA) profiles in the bulb scales and basal plates. Fructan concentrations decreased in the scales from harvest time onwards in the late-sprouting cultivar Hyfive, while remaining constant in the cultivar Exhibition until internal sprouting. In the basal plates, fructan concentrations increased in both cultivars from approximately one month after harvest, but reached maximum concentrations at moments that could not be related to the difference in internal sprouting. ABA levels generally decreased in the scales of both cultivars, while increasing in their basal plates. Nevertheless, for fructans, the measured variation in ABA concentrations was not consistently associated with differences in internal sprouting. A subsequent perturbation of internal sprouting by Maleic Hydrazide treatment in the cultivar Hyfive confirmed a lack of correlation. Altogether, this indicates that fructan and ABA levels in the scales and basal plate tissue change independent of internal sprouting and cannot be regarded as predictive markers for sprouting and storability. Full article

Onion (Allium cepa L.), a globally cultivated vegetable crop, possesses a shallow root system, making it vulnerable to abiotic stresses. The increasing frequency of extreme weather events in recent years necessitates sustainable solutions to enhance onion growth. Biostimulants offer a promising and accessible approach to promote onion growth and quality in an environmentally friendly and sustainable manner. This study investigated the effects of nine commercial microbial biostimulants (LALRISE Mycorrhizae, LALRISE Bacillus, Mighty Mycorrhizae, MycoApply, Spectrum DS, Spectrum Myco, Spectrum, Tribus Original, and Tribus Continuum) and one non-microbial commercial biostimulant (Kelpak—seaweed extract) on the seedling growth of three onion cultivars: Carta Blanca (white), Don Victoro (yellow), and Sofire (red). The results indicated that biostimulants did not significantly affect onion seed germination, but germination rates did vary among the onion cultivars. These cultivars also exhibited significant morphological and biomass differences, with principal component analysis revealing a more obvious effect on root growth compared to shoot growth. Kelpak seaweed extract increased the plant height, leaf area, and shoot fresh weight and dry weight of onion seedlings but decreased the root-to-shoot dry-weight ratio. The effects of microbial biostimulants on onion seedling growth depended on both the onion cultivar and Kelpak seaweed extract. In general, LALRISE Mycorrhizae, Mighty Mycorrhizae, Spectrum Myco, Spectrum DS, and Tribus Continuum exhibited positive effects on seedling growth in certain onion cultivars. Furthermore, the benefits of microbial biostimulants were amplified when combined with Kelpak seaweed extract application. These findings suggest a synergistic interaction between microbial and non-microbial biostimulants, leading to enhanced onion seedling growth. Further research is required to evaluate the long-term effects of these biostimulants on onion plant growth after transplanting to fields. Full article

Several Allium cepa L. varieties, representing a versatile set of vegetables widely utilized by consumers, are appreciated for their bioactive properties, including antimicrobial, anticarcinogenic, and antioxidant capacities. The aim of this study is to compare the morphometric characteristics and biochemical profiles of four cultivars of A. cepa, two of them represented by the perennial Sicilian landrace “Cipudda agghiarola” (Allium × proliferum (Moench) Schrader), widely known as the Egyptian walking onion (WO), and by the landrace “Cipudduzza” belonging to the variety known as aggregatum (ON), which were compared with two commercial cultivars of A. cepa var. cepa (onion), Stoccarda (OS) and Rossa Carmen (OR). The experimental trial was conducted in Catania (Sicily), following organic growing practices. The randomized complete block experimental design was adopted with one experimental factor, the genotype (GE) effect. The harvested plants were characterized for their main morphometric parameters, according to the International Plant Genetic Resources (IGPR) descriptors. The biochemical activity was assessed by analyzing the total phenolic content (TPC) and the total flavonoid content (TFC). The antioxidant capacity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC). The sugar profile (total sugars, sucrose, glucose, fructose, and fructooligosaccharides—FOS) and the volatile compounds by headspace-gas chromatography/mass spectrometry (HS-GC/MS) were also determined. The OR bulb exhibited the highest TPC (16.3 mg GAE/g d.w., p < 0.01) and TFC (8.5 mg QE/g d.w., p < 0.01), with the highest antioxidant capacity measured by the FRAP (27.1 µmol TE/g d.w., p < 0.01) and DPPH assays (46.2 µmol TE/g d.w., p < 0.01). The ON bulb showed the highest ORAC value (209 µmol TE/g d.w., p < 0.01). Generally, the bulbs were richer in sugars (584 mg/g d.w., p < 0.01) than the leaf blade (239 mg/g d.w., p < 0.01), except for OR. Significant interaction between the genotype and plant organ was noted in the volatile compound profiles (p < 0.05) except for total ketones and carboxylic acids, where higher content was observed in the leaf blade compared to the bulb, regardless of the genotype. These findings highlight WO’s potential for use in ready-to-eat products, enhancing its market value. Full article

Plant ploidy manipulation is often required for breeding purposes. However, there is no comprehensive review covering genome doubling in vegetable crops despite the abundance of data for a large number of vegetable species. Similar to other species, genome doubling is required in vegetable crops to obtain doubled haploids (DHs). It is also utilized for the production of polyploids to overcome interspecific hybrid sterility and improve agricultural traits. Spontaneous haploid genome duplication (SHGD) occurs in many Apiaceae, Brassicaceae, Cucurbitaceae, and Solanaceae crops, allowing for the laborious treatment with antimitotic agents to be bypassed. SHGD mechanisms are not fully understood, but existing data suggest that SHGD can occur via nuclear fusion, endoreduplication, or other mechanisms during microspore or ovule early embryogenic development. Other studies show that SHGD can occur at later developmental stages during extended plant growth in vitro or ex vitro, possibly due to the presence of phytohormones in the medium and/or diploid cell competitive advantage. For unresponsive accessions and species with rare SHGD, such as onion (Allium cepa L.) and beet cultivars (Beta vulgaris subsp. vulgaris L.), antimitotic agent treatment has to be applied. Antimitotic agent application efficiency depends on the treatment conditions, especially the agent concentration and exposure time. Also, plant developmental stage is critical for agent accessibility and plant survival. The existing methods can be used to further improve genome doubling methodology for major vegetable crops and other species. Full article

Allium vegetables attract attention for their flavor and aroma in Asia, especially in China and Japan. The aim of this experiment was to uncover the differences in the unique flavor compounds of two Welsh onions that are typical cultivars in China and Japan (‘Zhangqiu’ and ‘Tenko’). Chemical methods and solid-phase microextraction–gas chromatography-mass spectrometry were performed to determine the nutritional quality and quantity of volatile compounds of various organs of Welsh onions. The results show that a total of 30, 37, and 28 compounds were detected in the roots, pseudostem, and leaves of ‘Zhangqiu’, respectively, while 21, 27, and 20 compounds were detected in the corresponding organs of ‘Tenko’. The distribution of sulfur compounds in the roots, pseudostem, and leaves of ‘Zhangqiu’ accounted for 72%, 83%, and 26% of the total content, while those of ‘Tenko’ accounted for 55%, 84%, and 57%, respectively. Aldehydes are the second largest class of volatiles in Welsh onions. The distribution of aldehydes in the leaves was notably different: 52% and 27% in ‘Zhangqiu’ and ‘Tenko’, respectively. The contribution of S to the volatile substances was outstanding, and through forward selection, it was found that P, Ca, and Mg contribute to the volatile substances of Welsh onions. The above results indicate that the different genotypes of Welsh onions have various flavors, and mineral elements contribute variously to these flavors. Calcium could be a new topic of interest for our subsequent research on elements and volatiles. Full article

Fusarium basal rot (FBR) places a significant limitation on Allium production worldwide. The damage caused by the disease can be observed throughout the entire crop cycle. This research aimed to further our understanding of the impact of FBR on the cultivation of onions (Allium cepa) in northeast Israel. It focused on studying the composition and incidence of Fusarium species involved in disease outbursts in two representative fields, one in Galilee (Hula Valley) and the second in the Golan Heights, where the disease incidences reached 8%. Using colony morphology, microscopic taxonomic keys, and molecular methods, a new, unreported Neocosmospora (previously Fusarium solani) species complex (SC, mostly N. falciformis) was discovered as a wildly spread member of the Fusarium pathobiome community. This species complex appeared more generalist in its nature since it was found in all three onion cultivars’ samples. It was also less virulent in seed germination (42–52% higher sprout biomass, p < 0.05) and bulb pathogenicity tests (41–45% less necrotic) than Fusarium acutatum. Whereas the Galilee yellow Orlando (Riverside) onion cultivar bulbs sampled were colonized by Neocosmospora SC (70%) and two other, less abundant species, F. oxysporum f. sp. cepae and F. acutatum (15% each), the Golan Heights field’s Fusarium community showed host specificity. In the Golan Heights field, F. oxysporum f. sp. cepae inhabited the red Ha2 onion cultivar bulbs, whereas F. acutatum colonized the yellow Ha1 cultivar (40% and 50% prevalence along with Neocosmospora SC). A better understanding of the complexity of this disease caused by different Fusarium species and with a divergence in host susceptibility and virulence is critical for developing disease management strategies. Since each Fusarium species reacts differently to pest control treatments, changes in the species composition may require specifically adapted management solutions. Full article

Onions are typically consumed as the bulb, but the peel and root are discarded as by-products during processing. This study investigated the potential functional use of these by-products by analyzing the polyphenols, antioxidant compounds, and antioxidant activity contained in onions. In this study, the bulb, peel, and root of five onion cultivars (‘Tank’, ‘Bomul’, ‘Gujji’ ‘Cobra’, and ‘Hongbanjang’) harvested in Korea were investigated. Caffeic acid and quercetin were most abundant in the peel, whereas methyl gallate was the predominant polyphenol in the bulb. Both DPPH and ABTS radical scavenging activity were higher in onion peel and root than in the bulb. These findings suggest that onion peel and roots, which are often discarded, have abundant antioxidant substances and excellent antioxidant activity. This study provides basic data for the future use of onion peel and roots as functional ingredients with high added value. Full article

Soilborne pathogens reduce 60% of the yield of onion crops. A common fungal pathogen causing wilt disease and severe losses is Fusarium basal rot (FBR). In this study, the combination of Arbuscular Mycorrhizal Fungi (AMF) with Trichoderma harzianum was investigated against FBR. Onion samples were collected from the Ankara–Polatlı region. Among the isolates, isolate S6 was identified as F. oxysporum f. sp. cepae (FOC) using morphological and molecular methods and pathogenicity tests. Different combinations of AMF (Funneliformis mosseae pure strain and the commercial AMF) and T. harzianum were inoculated on susceptible onion cultivars (Seç, Gence, and Şampiyon). The effects of the treatments on FOC biocontrol were studied under growth chamber conditions. The results showed that Şampiyon was the most resistant, while Gence was the most susceptible to basal rot disease. Different colonization rates (8.91–24%), spore densities (16.4–50.4 spore/10 g soil), and the extent to which a plant needs mycorrhizal conditions to grow to its maximum potential (i.e., mycorrhizal dependencies—18.3–51.9%) were recorded by treatment. Both single and combined applications of AMF and Trichoderma applications suppressed FOC. Suppressive effects were more pronounced when the F. mosseae pure strain was used alone (when F. mosseae was used, disease severity decreased from 90 to 68%, p < 0.05). The F. mosseae pure strain also showed the best plant growth promotion and phosphorus content release. The results indicate an interesting potential use of F. mosseae and the combination of AMF with T. harzianum in the management of FOC in onions. Full article