Callus culture and regeneration from root tip of garlic (Allium sativum L.)

Callus induction and subsequent plant regeneration was studied in acommercial Indian cultivar of garlic, cV. G-41 (short-day type). 2,4-dicholorophenoxyacetic acid at lower concentration (0.25 mg 1-1) and picloram at higher concentration 1.0 mg 1") were suitable for efficient callus formation from the root tips. Callus was obtained only from the apical portions of root-tips treated with 2,4-dicholorophenoxyacetic acid whereas picloram led to callus fo rmation throughout the root segment except the non apical (subjacent) portion. Callus obtained from induction medium containing both auxins and cytokinins responded well toregeneration. The average shoot regeneration frequency ranged from 16.7% to 50.0%. The best combination for callus culture and regeneration was callus formation in root tip medium 2 (CRT 2) (2,4-d icholorophenoxyacetic acid 0.25 mg 1" + 6-benzylaminopurine 1.0 mg I'') induction medium followed by garlic regeneration medium 3 (GR 3) (ki netin 1.0 mg 1") as the regeneration medium. In other regeneration media, profuse root formation and appearance of dark green callus was also observed

Onion and Garlic Research in India

Onion and garlic research in India has produced 45 open-pollinated and two F1 hybrids in onion and approximately 25 varieties in garlic. Red onion is used for domestic consumption and export while the white onion is used mostly for processing. Improvement in garlic has been largely through clonal selection and mutation breeding. Somaclonal variations for development of varieties have not been used till now. Research on biotechnology for crop improvement in onion and garlic in India is in a nascent stage. While research on crop production has seen tremendous improvement, research on organic production and precision farming, good agricultural practices and mechanization needs to be carried out in future. Similarly, studies on plant protection have identified researchable issues for future work. This paper gives a brief overview of onion and garlic research scenario in India and technologies needed to be developed and practiced

Genetic diversity of morphological, biochemical and mineral traits in Indian onion (Allium cepa) genotypes

The present study was carried out during 2021 and 2022 at ICAR-Indian Agricultural Research Institute, New Delhi to evaluate the diversity among 83 onion (Allium cepa L.) genotypes utilizing morphological, biochemical, and mineral profiling. Substantial genetic variances were observed across all the investigated traits. Traits such as bulb phenol content, bulb pyruvic acid content, neck thickness, average bulb weight, iron, zinc, and sulphur recorded high genotypic coefficient of variance (GCV) and phenotypic coefficient of variance (PCV) values, whereas plant height, total soluble solids, marketable yield, dry matter, and calcium had moderate GCV as well as PCV values. High heritability was observed for all traits except for iron content, which ranged from 98.32% (bulb phenol content) to 37.93% (Iron). Principle Component Analysis (PCA) extracted 5 principal components (PC1–PC5), accounting for a cumulative variance of 59.88%. The primary contributors to PC1 were average bulb weight, marketable yield, and equatorial diameter, while PC2 was primarily influenced by iron content, bulb pyruvic acid content, and neck thickness. On the basis of Euclidean distance and Ward’s D2 analysis, all the genotypes were grouped into three clusters. Cluster 1 showed the highest values for dry matter, iron and zinc content. Cluster 2 consisted of genotypes with higher values for plant height, polar diameter, average bulb weight, calcium, potassium, and sulphur content, whereas it showed lower values for neck thickness. Cluster 3 exhibited higher values for equatorial diameter, total soluble solids and marketable yield. Greater genetic diversity offers breeders enhanced opportunities to identify promising genotypes for selection or utilization as parents in hybrid breeding programmes

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Not AvailableThe present experiment was conducted to investigate the effect of chemical mutagen on biological parameters such as seed germination, shoot and root length and to fix the lethal dose (LD50) of EMS in short day Indian onion cultivar Bhima Dark Red. Presoaked seeds of onion were treated with different doses (0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2 % v/v) of Ethyl Methane Sulfonate. The optimal mutagenic doses were calculated using Probit Analysis based on germination percentage which were considered useful in developing onion mutagenized population to create genetic variability for various qualitative and quantitative traits. Seed germination was recorded after 7 and 12 days of sowing, while seedling parameters such as seedling height, dry and fresh weight of seedlings were taken after 12 days. Data revealed that the mutagenic agent significantly reduced seed germination and seedling growth parameters in terms of shoot and root length as compared to control. Significant reduction in the seed germination percent with the enhancement of concentration of EMS dose was exhibited.Not Availabl

Recent Advances in Molecular Genetics of Onion

Onion is an important vegetable crop because it adds nutritional value and diversity to food preparation. Understanding recent advancements in onion molecular genetics is essential to improve production, quality, and disease resistance. Cutting-edge genomic technologies like genetic mapping and RNA sequencing reveal important genes and pathways. The review examines the progress in utilizing various molecular markers to study genetic divergence. The exploration extends to understanding the genes and pathways responsible for bulb color and chemical composition and the genetic factors influencing bulbing, flowering, and vernalization. Additionally, the article explores quantitative trait loci associated with resistance to major damaging diseases and delves into the role of different loci in male sterility and hybrid development. The recent publication of the whole genome sequence of onions will lead to further identification of genes and understanding their roles and functions in metabolic pathways

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Not AvailableOnion and garlic research in India has produced 45 open-pollinated and two F1 hybrids in onion and approximately 25 varieties in garlic. Red onion is used for domestic consumption and export while the white onion is used mostly for processing. Improvement in garlic has been largely through clonal selection and mutation breeding. Somaclonal variations for development of varieties have not been used till now. Research on biotechnology for crop improvement in onion and garlic in India is in a nascent stage. While research on crop production has seen tremendous improvement, research on organic production and precision farming, good agricultural practices and mechanization needs to be carried out in future. Similarly, studies on plant protection have identified researchable issues for future work. This paper gives a brief overview of onion and garlic research scenario in India and technologies needed to be developed and practiced.Not Availabl

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Not AvailableProduction of many crops, including onion, under salinity is lagging due to limited information on the physiological, biochemical and molecular mechanisms of salt stress tolerance in plants. Hence, the present study was conducted to identify salt-tolerant onion genotypes based on physiological and biochemical mechanisms associated with their differential responses. Thirty-six accessions were evaluated under control and salt stress conditions, and based on growth and bulb yield. Results revealed that plant height (6.07%), number of leaves per plant (3.07%), bulb diameter (11.38%), bulb yield per plant (31.24%), and total soluble solids (8.34%) were reduced significantly compared to control. Based on percent bulb yield reduction, seven varieties were classified as salt tolerant (with 40% yield reduction) and the remaining as moderately tolerant (with 20 to 40% yield reduction). Finally, seven salt-tolerant and seven saltsensitive accessions were selected for detailed study of their physiological and biochemical traits and their differential responses under salinity. High relative water content (RWC), membrane stability index (MSI), proline content (PRO), and better antioxidants such as super oxide dismutase (SOD), peroxidase (POX), catalase (CAT), and ascorbate peroxidase (APX) were observed in tolerant accessions, viz. POS35, NHRDF Red (L-28), GWO 1, POS36, NHRDF Red-4 (L-744), POS37, and POS38. Conversely, increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) content, reduced activity of antioxidants, more membrane injury, and high Na+/K+ ratio were observed in sensitive accessions, viz. ALR, GJWO 3, Kalyanpur Red Round, NHRDF Red-3 (L-652), Agrifound White, and NHRDF (L-920). Stepwise regression analysis identified bulb diameter, plant height, APX, stomatal conductance (gS), POX, CAT, MDA, MSI, and bulb Na+/K+ ratio as predictor traits accounting for maximum variation in bulb yield under salinity. The identified seven salt-tolerant varieties can be used in future onion breeding programs for developing tolerant genotypes for salt-prone areas.Not Availabl

Salt Tolerance Potential in Onion: Confirmation through Physiological and Biochemical Traits

Production of many crops, including onion, under salinity is lagging due to limited information on the physiological, biochemical and molecular mechanisms of salt stress tolerance in plants. Hence, the present study was conducted to identify salt-tolerant onion genotypes based on physiological and biochemical mechanisms associated with their differential responses. Thirty-six accessions were evaluated under control and salt stress conditions, and based on growth and bulb yield. Results revealed that plant height (6.07%), number of leaves per plant (3.07%), bulb diameter (11.38%), bulb yield per plant (31.24%), and total soluble solids (8.34%) were reduced significantly compared to control. Based on percent bulb yield reduction, seven varieties were classified as salt tolerant (with 40% yield reduction) and the remaining as moderately tolerant (with 20 to 40% yield reduction). Finally, seven salt-tolerant and seven salt-sensitive accessions were selected for detailed study of their physiological and biochemical traits and their differential responses under salinity. High relative water content (RWC), membrane stability index (MSI), proline content (PRO), and better antioxidants such as super oxide dismutase (SOD), peroxidase (POX), catalase (CAT), and ascorbate peroxidase (APX) were observed in tolerant accessions, viz. POS35, NHRDF Red (L-28), GWO 1, POS36, NHRDF Red-4 (L-744), POS37, and POS38. Conversely, increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) content, reduced activity of antioxidants, more membrane injury, and high Na+/K+ ratio were observed in sensitive accessions, viz. ALR, GJWO 3, Kalyanpur Red Round, NHRDF Red-3 (L-652), Agrifound White, and NHRDF (L-920). Stepwise regression analysis identified bulb diameter), plant height, APX, stomatal conductance (gS), POX, CAT, MDA, MSI, and bulb Na+/K+ ratio as predictor traits accounting for maximum variation in bulb yield under salinity. The identified seven salt-tolerant varieties can be used in future onion breeding programs for developing tolerant genotypes for salt-prone areas

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Not AvailableOnion (Allium cepa L.) contributes more than 50% of the net export earnings among fresh vegetable exports in India. Stemphylium blight and purple blotch are the most destructive fungal diseases in the tropics and cause 80–90% losses in bulb and seed crop. Our aim was to screen multiple onion accessions against Stemphylium blight under artificially inoculated conditions, assess morphological and biochemical traits and correlate the observed trait with disease incidence. Screening of fifty-nine accessions resulted in identification of ‘Pusa Soumya’ (A. fistulosum L.) and ‘Red Creole2’ (A. cepa L.) as moderately resistant and ‘Red Creole1’ as susceptible. Highest marketable yield was recorded in ‘AFW’ (28.00 t/ha) followed by ‘Punjab Naroha’ (25.85 t/ha) in New Delhi, whereas in Karnal, ‘AKON555’ (45.85 t/ha) performed best. Pooled analysis revealed highest marketable yield in ‘PWF’ (44.56 t/ha). These varieties have exhibited field tolerance and in the absence of credible resistance can be recommended for areas where Stemphylium blight is the major problem. Significant variation in foliage weight, gross yield, marketable yield, dry matter, total soluble solids, total phenolic content and pyruvic acid content were recorded between non-inoculated and inoculated field trials which suggests the devastating effect of this disease on onion crop. Pearson’s correlation coefficient exhibited that percent disease index (PDI) was significantly and positively correlated with average bulb weight, gross yield, marketable yield. Significant negative correlation (r = −0.30) between dry matter and PDI (p < 0.05) and significant negative correlation (r = −0.35) between ATP (total foliar phenols after inoculation) and PDI were observed. This signifies that dry matter and total foliar phenol content can be used as a biochemical marker for high throughput screening against Stemphylium blight at preliminary screening stage. Further, ‘Pusa Soumya’ and ‘Red Creole2’ can be used as parent material to study the inheritance mechanism and for breeding of Stemphylium blight resistant onions under short day tropical conditions.Not Availabl

Field Screening of Garlic Genotypes for Identification of Resistant Sources against Purple Blotch Disease

Garlic (Allium sativum L.) is one of the oldest cultivated plants in the world and belongs to the family Amaryllidaceae. Purple blotch caused by Alternaria porri (Ellis) Ciferri is one such disease which causes a great deal of loss for farmers. The best method to manage purple blotch is to adopt resistant genotypes for cultivation, which is highly necessary in areas with a high incidence. In order to identify resistant sources, 37 genotypes were field screened under artificial epiphytotic conditions at AINRPOG (All India Network Research Project on Onion and Garlic), MARS (Main Agricultural Research Station), Dharwad during Rabi, 2019 and 2020. Results from two years showed that no genotype was immune to purple blotch. Among the genotypes tested, five genotypes viz., G50, Bhima Purple, DOGR426, DOGR543 and DOGR569 were resistant to infection (1-10%), 17 genotypes moderately resistant to infection (11-20%), while 4 genotypes were moderately susceptible to infection (21-40%). On a scale of 0 to 5, only one genotype (HRG Local) showed susceptible (41-75%) in reaction. Among the remaining genotypes, disease reactions differed between years. The genotypes that are resistant can be utilized by breeders to produce high yielding purple blotch resistant varieties