Hybrid Onion Research Articles

Selênio como um bioestimulante inorgânico em cebola cultivada em clima semiárido

ABSTRACT The common climatic characteristics in semi-arid regions can cause abiotic stress and be a limiting factor for crops. Under these conditions, the use of beneficial elements such as selenium (Se) is an alternative to mitigate the harmful effects of abiotic stresses and increase yield. Therefore, this research aimed to evaluate the agronomic performance of onion grown in a semi-arid region under the application of Se. A field experiment was performed in a randomized block design, where five doses of Se (0, 15, 30, 45, and 60 g ha-1), by foliar application, were tested on two onion hybrids (Andrômeda and Rio das Antas). Growth, nutritional and yield variables were analyzed. Se increased the height and accumulation of dry mass in onion plants, with a maximum at the 60 g ha-1 dose of Se, the same dose at which the highest commercial (78.15 t ha-1) and total (86.03 t ha-1) bulb yields were obtained in Rio das Antas; however, for Andrômeda, there was no effect of Se on yield. Applied Se doses also increased the content of this element in the bulbs. Despite increasing bulb yields only in the Rio das Antas hybrid, 60 g ha-1 of Se is recommended for onions due to its effects on plant growth and the biofortification of bulbs with Se.

Yield potential of onion genotypes in the Planicie Huasteca, Mexico

Objective: To identify new generation onion genotypes with high yield per unit that meet the bulb quality characteristics required by the export market.
 Design/Methodology/Approach: Eight onion hybrids with yellow bulb, six hybrids with white bulb, and three hybrids with purple bulb were evaluated. The experiments were established with drip irrigation and fertigation. The agronomic characteristics of the plant and the production and quality of the bulb were evaluated, using the USDA specifications for bulb width and shape. The experiments were carried out using a completely randomized block design, with three replications; the statistical analysis was performed using the SAS software, version 9.2.
 Results: The best onion genetic materials for the Planicie Huasteca were the yellow bulb hybrids Wayne and Don Víctor, the white bulb hybrids Blanca Grande, Monja Blanca, and Don Alberto, and the purple bulb hybrid Rasta, all of which have high production capacity and bulb quality.
 Study Limitations/Implications: Onion (Allium cepa L.) is the most extensive horticultural crop in the Planicie Huasteca, Mexico. Although regional producers establish outstanding genotypes, they require information about the new generation genetic materials, if they are to remain competitive in the export market. Therefore, the new genotypes with the best high yield potential and bulb quality must be evaluated to select those that meet the requirements of the market.
 Findings/Conclusions: Yellow, white, and purple bulb onion genotypes with high production capacity that meet the requirements of the markets were identified.

Enhancing bulb yield through nitrogen fertilization and the use of hybrid onion (Alluim cepa L.) varieties in northwest Ethiopia.

Onions are among the most important cash crops in developing countries, including Ethiopia. However, its production and productivity are very low, which is associated with inappropriate fertilization and the use of low-yielding varieties. Therefore, the present study was conducted to evaluate the effects of the nitrogen fertilizer rate on the growth, yield, and quality of hybrid onion varieties in northwest Ethiopia. The experiment was conducted at three locations (Koga, Woreta, and Woramit) during the 2021/2022 cropping season under irrigated conditions. The treatments consisted of three hybrid onion varieties (Russet, Jambar, Red Coach) and one open-pollinated onion variety (Bombay Red) and four nitrogen rates (0, 41, 82, and 123 kg ha-1), which were laid out in a randomized complete block design with a factorial arrangement of 4*4 in three replications. The results of the present study revealed that onion growth, yield and quality were influenced by the nitrogen fertilizer rate and onion variety across all locations. Compared with the open pollinated Bombay Red variety, the hybrid varieties (Russet and Jambar) performed well in terms of bulb diameter, bulb weight, total yield, marketable bulb yield, and pungency. Nitrogen fertilizer applied at a rate of 82 kg ha-1 resulted in the highest growth and yield parameters of onion. The Russet and Jambar varieties recorded the highest marketable bulb yields of 26.50 t ha-1 and 24.57 t ha-1, respectively. Onion varieties treated with the highest nitrogen fertilizer dosage of 123 kg ha-1, particularly the Bombay Red variety, exhibited the longest duration to reach maturity. Onion plants supplied with 82 kg ha-1 nitrogen presented the highest marketable bulb yields, with a value of 26.77 t ha-1. Too much nitrogen above 82 kg ha-1 leads to decreased yield; hence, excess nitrogen is lost to the environment. Furthermore, the Jambar and Russet hybrid varieties and the application of 82 kg ha-1 nitrogen fertilizers provided the highest net benefit. The hybrid varieties Jambar and Russet and the application of 82 kg ha-1 nitrogen fertilizer can be recommended for onion production in the study area and areas with similar agroecosystems. Since this study is the first of its kind, considering other hybrid onion varieties and optimizing agronomic practices such as spacing and phosphorus fertilizer are also recommended in future research.

ВЫРАЩИВАНИЕ ЛУКА РЕПЧАТОГО В ЮЖНОМ РЕГИОНЕ РОССИИ

Relevance. Onions are a fairly technological crop and one of the most in–demand and widely consumed by the population among vegetable crops throughout the year. Under optimal conditions, onions can be freely stored for 6...8 months. The yield potential of this crop is from 90.0... to 100.0 or more tons per hectare. The conducted research determines promising ways to increase the yield of this important crop. The object of the study was experiments conducted on the territory of the private enterprise Zvolinsky O.V., located in the southeastern European part of Russia (Northwestern Caspian Sea), on the land use of the Chernoyarsk district of the Astrakhan region, which is part of the cascade of the northernmost corners of the region. The subject of the study were two onion hybrids: Burgus and Valero with the use of growth stimulants Potassium humate liquid peat and Flora - C for specified yield levels of 80.0; 100, and 120.0 t/ha, using the calculated amount of nutrients for the appropriate levels. Two irrigation regimes were studied: 70...70...70% NV (permanent) and 80...80...70% NV (differentiated). Results and conclusions. The conducted studies have shown that the studied growth stimulants have shown positive effects on the growth of onion yields. If in the variant without the use of growth stimulants, the yield on the Valero hybrid varied from 96.31 t/ha (constant mode) to 103.75 t/ha (differentiated mode). Accordingly, on the Burgus hybrid from 85.09 to 92.32 t/ha. The maximum effect was obtained from the use of the Flora – C growth regulator on the Valero hybrid. Yield levels, depending on the moisture threshold, ranged from 101.29 to 111.45 t/ha. While on the Burgus hybrid, similar values ranged from 95.39 to 105.91 t/ha

A Single Nucleotide Polymorphism Unique to the Galanthum-CMS of Onion

Different sources of cytoplasmic male sterility (CMS) are used to produce hybrid onion seed. The most commonly used source of CMS in onion is S cytoplasm (S-CMS), and male fertility is restored by a dominant allele at the nuclear male-fertility restoration locus (Ms). Male-sterile plants possess S cytoplasm and have the homozygous recessive genotype at Ms; seed propagation of male-sterile plants is possible by crossing with a male-fertile maintainer plant or inbred possessing normal (N) male-fertile cytoplasm and the homozygous recessive at the Ms locus (N msms). Some commercially important onion populations possess S-CMS and high frequencies of the dominant Ms allele, eliminating the possibility to develop maintainer lines. An alloplasmic source of CMS (Gal-CMS) was developed by backcrossing the cytoplasm of Allium galanthum into the nuclear background of onion. The advantage of Gal-CMS is that the dominant allele at Ms does not restore male fertility, making this source of CMS useful for the development of male-sterile lines from populations possessing S cytoplasm and dominant allele(s) at Ms. In this research, a single nucleotide polymorphism unique to the cytoplasms of A. galanthum and Gal-CMS was identified, useful to distinguish Gal-CMS from other onion cytoplasms.

Growth, Yield and Economic Advantage of Onion (Allium cepa L.) Varieties in Response to NPSB Fertilizer and Planting Pattern

Haphazard and low soil fertility, low yielding verities and poor agronomic practices are among the major factors constraining onion production in the central rift valley of Ethiopia. Therefore, a field experiment was conducted in East Showa Zone of Adami Tulu Jido Combolcha district in central rift valley areas at ziway from October 2021 to April 2022 to identify appropriate rate of NPSB fertilizer and planting pattern of onion varieties. The experiment was laid out in split plot design of factorial arrangement in three replications. The main effect of NPSB blended fertilizer rates and varieties (red coach and red king) significantly (p<0.01) influenced plant height, leaf length, leaf diameter, leaf number and fresh leaf weight, shoot dry matter per plant, and harvest index. Total dry biomass, bulb diameter, neck diameter, average fresh bulb weight, bulb dry matter, marketable bulb yield, and total bulb yield were significantly (p<0.01) influenced only by the main effect of NPSB blended fertilizer rates. In addition, unmarketable bulb yield was statistically significantly affected (p≥0.05) by the blended fertilizer rates and planting pattern. Moreover, days to 90% maturity of onion was affected by the main factor of NPSB fertilizer rate, variety and planting pattern. The non-fertilized plants in the control treatment were inferior in all parameters except unmarketable bulb yield and harvest index. Significantly higher marketable bulb yield (41 t ha-1) and total bulb yield (41.33 t ha-1) was recorded from 300 kg ha-1 NPSB blended fertilizer rate applied. Double row planting method and hybrid red coach onion variety had also gave higher growth and yields. The study revealed that the highest net benefit of Birr, 878,894 with lest cost of Birr 148,006 by the combinations of 150 kg blended NPSB ha-1 with double row planting method (40cm*20cm*7cm) and red coach variety which can be recommendable for higher marketable bulb yield and economic return of hybrid onion for small scale farmers in the study area. Also, for resource full producers (investors), highest net benefit of Birr 1,205,372 with higher cost (159,628 Birr) by application of 300 kg NPSB ha-1 is recommended as a second option. However, the research should be replicated both in season and areas to more verify the recommendations.

Yield of Syn-1 synthetic varieties of tropical onion resulting from openpollinated Brazilian populations

Due to technological limitations for the development of onion hybrids, first-cycle synthetic varieties (Syn1-SV) could be an alternative to partially explore heterotic vigor. The growing areas of onion hybrids in Brazilare mainly defined by bulb yield and uniformity. From this perspective, the present study aimed to developtropical onion Syn1-SV and estimate mid-parent heterosis (Hm), heterobeltiosis (Hp), and standard heterosis(Hs) as an alternative to hybrid development. Six Syn1-SVs, eight open-pollinated (OP) populations, and onecommercial hybrid were evaluated in a randomized block design with three replications, in two semesters, forthe commercial bulb yield (CBY) and days to bulb harvest (DBH). Significant differences were observed fortreatments (T), semesters (S) and the T*S interaction for both variables (p-value<0.05). The OPs ‘Alfa SF RT’ inthe first semester and ‘IPA11’ in the second semester were the most precocious treatments. The highest CBYwas estimated in the commercial hybrid (105.8 t ha-1) and in ‘Alfa SF RT’ (45.5 t ha-1) in the first and secondsemesters, respectively. Three Syn1-SVs showed positive Hm values, ranging from 2.0% to 6.3% for CBY. ThreeSyn1-SV showed positive Hp values in the first semester, ranging from 3.0% to 5.2%, for CBY. Only the Syn1-SV ‘AlfaSF RT’ × ‘BRS Alfa São Francisco’ (48.9 t ha-1) showed positive Hs values, surpassing by a small value the controlOP population ‘IPA11’ (48.0 t ha-1), indicating the potential of Syn1-SV as an option for onion hybrids.

Antimicrobial activities, phenolic and flavonoid contents, antioxidant and DNA protection of the internal and outer layers of Allium cepa L. from Iran

Allium cepa L., known as a wild onion in Iran with different high antioxidant and antimicrobial activities in internal and outer layers. The aim of this study was to assess phenolic and flavonoid contents as well as antioxidant and antimicrobial activities of the internal and outer layers of ten Iranian onions (Allium cepa L.) landrace and compare them with three hybrid onions. Results showed that the total phenolic, flavonoid contents and the antioxidant capacity of the onions ranged 18.76–65.25 (mg GAE/g DW), 0.06–1.92 (mg/g DW) and 10.34–40.54%, respectively. The results showed higher total phenolic and flavonoid content as well as antioxidant activity and protection of pBR322 DNA in the outer layer in compare to internal ones due to higher hydroxyl radicals. Based on the results, the present study showed that red onions such as landraces originated from Azarshahr and Nowshahr included the highest quantities of phenolic and flavonoid contents as well as antioxidant activity and DNA protection values. Inhibition zone and minimum inhibitory and minimum microbicidal concentration of internal layer of onion from Kahrizak were significantly different from others (p < 0.05). This research showed the potential of Iranian onions as a natural preservative and good antioxidant.

The role of a microbial consortium on gas exchange and water relations in Allium cepa L. under water and nutritional deficit conditions

Synergistic studies of microorganisms in the last decade have been mostly directed towards their biofertilizing effects on growth and crop yield. Our research examines the role of a microbial consortium (MC) on physiological responses of Allium cepa hybrid F1 2000 under water and nutritional deficit in a semi-arid environment. An onion crop was established with normal irrigation (NIr) (100% ETc) and water deficit (WD) (67% ETc) and different fertilization treatments (MC with 0%, 50% and 100% NPK). Gas exchange (Stomatal conductance (Gs), transpiration (E) and CO2 assimilation rates (A)) and leaf water status were evaluated throughout its growth cycle. The MC + 50% NPK treatment with NIr maintained similar A rates to the production control. A. cepa decreased Gs by approximately 50% in the WD treatment. The highest water use efficiency (WUE) and an increase in the modulus of elasticity in response to water stress were obtained for the 100% NPK treatment under non-inoculated WD. The onion hybrid F1 2000 was tolerant to water stress and under non-limiting nutrient conditions, irrigation may be reduced. The MC facilitated the availability of nutrients under NIr allowing a 50% reduction in the application of high doses of fertilization without affecting yield, resulting in a suitable agroecological strategy for this crop.

Identification of a candidate gene responsible for male sterility conferred by CMS-T cytoplasm in onion (Allium cepa L.) and development of molecular markers for detection of CMS-T cytoplasm

Cytoplasmic male sterility (CMS) has been exclusively used as an emasculation tool in seed production of hybrids in onion (Allium cepa L.).Three types of onion CMS (CMS-S, CMS-R, and CMS-T) have been used in hybrid onion breeding. Male sterility conferred by both CMS-S and CMS-R is likely induced by open reading frame (orf) 725, a chimeric gene. However, this gene was not detected in onion accessions containing CMS-T cytoplasm. Instead, a region showing high homology with orfA501, which is located in the 3’ end of orf725, was detected in CMS-T. A novel chimeric gene, which we named orf219, was identified by genome walking PCR amplification based on the orfA501 homolog. The 684-bp open reading frame of orf219 consisted of an 128-bp of exon 1 of atp1 and a 556-bp sequence of an orfA501 homolog. The high-copy-number orf219 was detected only in the CMS-T cytoplasm (T cytotype). Analysis of RT-PCR products showed normal transcription of orf219 and eight RNA editing sites, one of which created a stop codon, resulting in a shorter amino acid sequence upon translation. Sequences of four hypervariable regions in the chloroplast genome and the organization of syntenic blocks in mitochondrial genome indicated that CMS-T was very closely related to the normal (N) male-fertile and CMS-R cytotypes. Based on these findings, new molecular markers were developed for the identification of cytotypes CMS-T, -R, -S, and -N. Cytotypes of 424 diverse onion accessions were identified using six molecular markers. The CMS-S and CMS-R cytotypes predominated among the analyzed accessions. In contrast, only five accessions possessed CMS-T, supporting earlier reports that CMS-T is rarely used in hybrid-onion breeding.

A simple and efficient method for onion pollen preservation: Germination, dehydration, storage conditions, and seed production

The preservation of viable pollen is essential to overcome the problems related to the asynchronous flowering of the parental lines in onion hybrid breeding programs. The aim of this study was to establish a simple, inexpensive, and easily reproducible protocol for medium-term onion pollen storage. First, the conditions for assessing the in vitro pollen germination were optimized. The liquid medium favored the counting of germination of pollen grains in comparison to the solid medium. The addition of 75 mg/l Ca(NO3)2. 4H2O to the medium did not improve pollen germination, while that of 150 mg/l Ca(NO3)2. 4H2O inhibited pollen germination. The highest germination percentage was achieved by incubation at 30–35 °C in the dark. Second, fresh or dehydrated pollen (maintained in a desiccator with silica gel at 25 °C for 18 h) was stored at 4, –20, and –80 °C for two years to study pollen preservation. In addition, the viability and germination capacity of stored pollen were periodically evaluated at 0, 15 and 30 days; 2 and 6 months; and 1 and 2 years. Pollen viability was best retained at low relative humidity and temperatures below zero. Dehydration was essential for pollen preservation at –20 and –80 °C. The results showed that dehydrated pollen stored at –20 °C could be used, with guarantees, for pollination throughout the flowering season. However, the highest viability and in vitro germination percentages after two years of storage (29 and 32%, respectively) were achieved with dehydrated pollen stored at –80 °C. Finally, the capacity of stored pollen to produce seeds was confirmed in crosses with male sterile lines. In this way, dehydrated pollen stored at –80 °C for two years produced an average of 47.9 seeds/100 flowers, representing 43% of the seed in the control crosses. This is the first report in onion research of seed production after pollination with preserved pollen at –80 °C for two years.

Performance of a semi-glossy onion hybrid in certified organic onion fields infested with Thrips tabaci and bulb-rot causing bacteria

More than one-third of the certified organic farms that produce dry bulb onions in the USA are in the Great Lakes region, while onion thrips, Thrips tabaci Lindeman, and bulb-rot causing bacteria are important onion production constraints. Onion cultivars with semi-glossy foliage have been reported to support fewer thrips and suffer less thrips damage and therefore may provide a non-chemical option for thrips management. However, inconsistent results regarding efficacy of semi-glossy onions to reduce thrips densities have been reported in field studies. Bacteria causing bulb rot can infect onion plants through wounds in leaves, but the relationship between thrips damage and bacterial bulb rot disease needs further investigation. In this study, the performance of a semi-glossy onion hybrid, ‘USDA Maia’, was compared with the commonly grown waxy, thrips-susceptible cultivar ‘Bradley’ on certified organic farms in New York and Wisconsin from 2019 to 2021. Results indicated that thrips abundance was not different between ‘USDA Maia’ and ‘Bradley’. Bacterial bulb rot incidence in ‘USDA Maia’ was either similar or lower than the incidence in ‘Bradley’ in four of six trials, but higher in the other two. Marketable bulb yield in ‘USDA Maia’ was similar to yield in ‘Bradley’ in four of seven trials, but lower in the other three. Positive relationships between thrips density and bacterial bulb rot incidence occurred in one of three trials for both onion cultivars. Similarly, negative relationships between thrips density and marketable bulb yield only occurred in one of three trials, regardless of onion cultivar. ‘USDA Maia’ did not reduce thrips infestations as anticipated, but it was similar in susceptibility to bacterial bulb rot disease and produced similar large bulb yields as ‘Bradley’. While high thrips abundance can potentially increase incidence of bacterial bulb rot disease, wet growing conditions during bulbing was more important.

Produtividade, qualidade físico-química e resistência ao florescimento precoce de híbridos experimentais de cebola

ABSTRACT In order to produce bulbs or seeds, onion plants depend on genotype X environment interaction. Thus, breeders shall select the genotypes based on the climatic conditions of each producing region. This study aimed to evaluate 17 experimental onion hybrids and two commercial genotypes (‘Bella Dura’ and ‘Buccaneer’), based on agronomic, physicochemical attributes of the bulbs and resistance to early flowering under subtropical conditions. Joint analysis of variance and phenotypic divergence estimated through principal component analysis (PCA) and Ward’s hierarchical clustering were performed. We observed that the time of transplantation affected the agronomic traits more than the physicochemical traits, not affecting the percentage of early flowering of the genotypes. The first transplant season provided higher bulb productivity, whereas the second season reduced the cycle and productivity. Hybrids H1, H17 and ‘Buccaneer’ showed flowering rate lower than 3%. Among the experimental hybrids, H2 showed higher productivity when comparing with commercial cultivars, and H1, H12 and H14 were equivalent to them. However, H12 showed the highest early flowering rate (43%). Thus, considering the experimental genotypes evaluated under subtropical conditions, H1, H2, and H14, showed potential for commercial use or as potential parents in advancing the breeding program, as they stood out for presenting good yield, bulb quality and low percentage of early flowering.

Molecular marker-based characterization of cytoplasm and restorer of male sterility (Ms) locus in commercially grown onions in India.

The cytoplasmic-genic male-sterility system has been extensively employed for the production of onion hybrids. Molecular marker-assisted characterization of the cytotypes and genotyping at the restorer-of male-fertility (Ms) locus is important for the accelerated breeding of onion hybrids. Indian onion breeding has focussed more on open-pollinated varieties than hybrids. To accelerate the breeding efforts, marker-assisted selection (MAS) plays a pivotal role. This study aimed to characterize the Indian breeding lines, varieties, hybrids, and exotic accessions for cytotype and Ms locus. For cytoplasm, cytotype markers, accD, and MKFR and for Ms locus identification, PCR markers AcPMS1 and AcSKP1 were employed. Bulk strategy to identify cytoplasm and Ms locus was tested. Sequencing of PCR products amplified by accD was also tried. Both the accD and MKFR were synonymous in cytoplasm identification except in T821 where T cytoplasm was identified. AcPMS1 was more reliable than AcSKP1 for Ms locus identification. Sequencing proved that N and T cytoplasm are identical. Bulking strategy can be used for cytotype identification but not for Ms locus. Indian onions have a predominance of normal (N) cytoplasm and homozygous recessive (msms) locus. This might be beneficial for hybrid development. S cytoplasm was identified in exotic varieties. For the first time, T cytoplasm has been reported from India. These findings will assist Indian onion breeders to develop MAS strategies for accelerating hybrid development programs. And for the release of onion hybrids with high productivity and uniformity.

ANALYSIS OF DRIP IRRIGATION OF ONION HYBRIDS IN THE ZONE OF LIGHT CHESTNUT SOILS OF THE LOWER VOLGA REGION

The analysis of the combination of climatic features of the Lower Volga region zone with drip irrigation for the development of onion production is carried out. This substantiation of the elements of irrigation technology for highly productive onion hybrids using drip irrigation systems provides a rational combination of resource consumption and the output of environmentally safe products, as well as the formation of record yields.

Hybrid Onion Layered System for the Analysis of Collective Subjectivity in Social Networks

This research aims to analyze the Digital Social Networks (DSN) behavior, constructed from the network’s relationships, interactions, and expressions of users’ private states through collective subjectivity. For this purpose, an onion-ring system called COSSOL has been built in a case study for Twitter, following a hybrid approach to integrate Machine Learning classifiers and structural metrics from Computational Linguistics and Computational Sociology disciplines, respectively. The paper designs two experimentation scenarios divided into cases of collective subjectivity analysis for Colombia under different levels of communities’ granularity. The first case validates the system by performing a cointegration test on the metrics of each construct for the onion rings’ communities. The results show that some communities better propagate their subjective expressions against the disclosed topic when they have a higher network density and a common polarity. Moreover, the most stable communities in polarity towards a topic are those whose members are highly connected. Conversely, communities with a higher centrality index in a subset of members do not exhibit stability in collective subjectivity towards a topic disclosed in that community. The second case validates the model with a series of Social Network Analysis (SNA) metrics with a polarity layer to describe the second onion ring subcommunities and their temporal variation through community recalculation. The results show no polar distributions similar to the bimodal ones representing consensus in the values of the common Thinking Acting and Feeling (TAF) forms. In addition, general negative sentiment is identified for the ten most representative nodes of the subcommunities analyzed.

Effects of static magnetic fields on onion (Allium cepa L.) seed germination and early seedling growth

In vegetables of economic importance such as onion, one of the main limitations in their production is that their seeds have a relatively short storage life, so their viability decreases rapidly. Research has been carried out on onions to improve seed germination and to extend its use for sowing. The magnetic field is considered a simple, inexpensive, and non-invasive physical method to stimulate the germination process, compared to traditional chemical methods. In this sense the objective of this research were to evaluate the effects of static magnetic fields on Yellow Granex PRR hybrid onion (Allium cepa L.) seed germination, and early growth in the laboratory conditions. Seeds were exposed to 10 and 21mT, (mT=militesla), static magnetic fields induced by magnets for 0, 5, 3, 6, 12 and 24h; each treatment had four repetitions. The results showed that the low intensity stationary magnetic fields (10 and 21mT) did not cause significant differences in germination, dry weight, or fresh weight, but for the seedling length. It is necessary to increase the intensity of the magnetic fields and the exposure time to achieve important physiological changes that positively affect the germination and growth of onion seeds, and thus contribute to the improvement of their yield and productivity. The use of physical methods such as magnetism can stimulate different physiological processes in plants and thus contribute to the improvement of characteristics of agronomic interest.

Effects of static magnetic fields on onion (Allium cepa L.) seed germination and early seedling growth

In vegetables of economic importance such as onion, one of the main limitations in their production is that their seeds have a relatively short storage life, so their viability decreases rapidly. Research has been carried out on onions to improve seed germination and to extend its use for sowing. The magnetic field is considered a simple, inexpensive, and non-invasive physical method to stimulate the germination process, compared to traditional chemical methods. In this sense the objective of this research were to evaluate the effects of static magnetic fields on Yellow Granex PRR hybrid onion (Allium cepa L.) seed germination, and early growth in the laboratory conditions. Seeds were exposed to 10 and 21mT, (mT=militesla), static magnetic fields induced by magnets for 0, 5, 3, 6, 12 and 24h; each treatment had four repetitions. The results showed that the low intensity stationary magnetic fields (10 and 21mT) did not cause significant differences in germination, dry weight, or fresh weight, but for the seedling length. It is necessary to increase the intensity of the magnetic fields and the exposure time to achieve important physiological changes that positively affect the germination and growth of onion seeds, and thus contribute to the improvement of their yield and productivity. The use of physical methods such as magnetism can stimulate different physiological processes in plants and thus contribute to the improvement of characteristics of agronomic interest.

Perspectives of onion hybrid breeding in India: An overview

Onion (Allium cepa L.), a major member of monocot family Amaryllidaceae, is an important bulbous vegetable cropused in almost every Indian kitchen. Being cultivated since antiquity, farmers rely on growing open pollinated varietiessince hybrid development in this crop has not gained pace. Among important vegetables, F1 hybrid developmentremains underutilized in onion especially in India and other developing countries as compared to other onion growingcountries. Development of commercial hybrids in onion principally depends on the availability of suitable inbredlines against the backdrop of stable male sterile system. The future scope of commercial onion hybrids needs to befocused comprehensively for the identification of male sterile lines from Indian onion population by utilizing modernbiotechnological tools. Molecular markers distinguishing cytoplasm and linked to restorer of male sterility, Ms locus,are important. Release of commercial hybrids from public sector would play a great role for breaking yield barriers andsignificant enhancement of productivity of onion under changing climate scenario and increasing domestic demand.

Drip irrigation of onions

From 2017 to 2020, research was conducted in the Volgograd region in order to improve the efficiency of water and mineral nutrition management of onions by justifying the calculated layer of soil moisture and agrotechnical methods of cultivation on light chestnut soils to obtain 110 t/ha of marketable products. The main objectives of the research include the rationale for the formation of the water regime of the soil and drip irrigation regimes depending on the wetted soil, the study of patterns of growth, development and yield formation of onion depending on the studied factors, economic and environmental assessment of drip irrigation technology, the quality of the bulbs, depending on the studied factors. The field experience included the following options: water regime of the soil (factor A), mineral nutrition regime (factor B), promising onion hybrids (factor C).The studies were carried out on onion crops C1 – Migros F1; C2 – Dragon F1 ; C3 - Dammica F1. Against the background of the introduction of N180P80K70, the Migros F1 hybrid provides an average of 94.3 t/ha of onions in 3 years of research, which is 16.6 t/ha more in comparison with the Dragon F1 onion; and 2.2 t/ha more in the Dammica F1 hybrid.