Browsing by Author "R.K. Tyagi"

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Basic parameters of open star clusters DOLIDZE 14 and NGC 110 in infrared bands
(Elsevier, 2015) Gireesh C. Joshi; Y.C. Joshi; S. Joshi; R.K. Tyagi
The basic physical parameters of a poorly studied open cluster NGC 110 and an unstudied open cluster DOLIDZE 14 are estimated in the present study using the archival PPMXL and WISE catalogues. The radius of both the clusters are estimated by fitting the modified King's empirical model on their stellar density profiles. The other basic parameters of the clusters such as distance, reddening, and age are obtained by visual fitting of the Marigo's solar metallicity isochrone on their IR colour-magnitude diagrams (CMDs). The mean-proper motion of the clusters are estimated through the individual proper motion of probable members identified through the dynamical and statistical methods. The archival catalogues (JHKW1W2) are constructed for both the clusters by compiling the extracted data from the PPMXL and WISE catalogues. The various colour-excesses, such as E(J-H),E(H-K) and E(W1-W2), are estimated using the best fit theoretical isochrone on the (J-H)-H,(H-K)-H and (W1-W2)-H CMDs, respectively. The ratios of various infrared colours of the clusters are obtained through their two-colour diagrams. We also identify the most probable members in these clusters by estimating spatial, kinematic and spatio-kinematic probabilities of stars within the cluster. A correlation between the E(H-K) and E(W1-W2) is also established. © 2015 Elsevier B.V.
Biochemical markers of environmental stress tolerance in finger millet [Eleusine coracana (L.) Gaertn.] germplasm of Central Himalayan Region
(Springer Science and Business Media B.V., 2022) A.K. Trivedi; S.K. Verma; R.K. Tyagi; A. Hemantaranjan; Achal Singh
Availability of the germplasm of suitable crops for cultivation in environmental stress prone and resource poor terrains is crucial for food security in these regions. Rich diversity of millets, which are highly tolerant to extreme weather conditions, is obtainable in the Central Himalayan Region (CHR). However, biochemical evaluation of available germplasm for food security is a major apprehension yet to be addressed properly. In this backdrop expeditions were conducted to tap and evaluate the germplasm variability of finger millet [Eleusine coracana (L.) Gaertn.]. Germplasm accessions (314) having traits of agronomic importance were collected and evaluated for three consecutive years. In addition to set of biochemical traits, yield was recorded to find out suitable germplasm for large scale cultivation/breeding programme. At flowering stage variability in antioxidants level of leaves such as glutathione and ascorbate ranged from 105.27 to 423.63 mmol g−1 FW and 4.89–10.21 mmol g−1 FW respectively. Extensive variableness in the activity of enzymes which are important for multiple abiotic stress tolerance viz., catalase (115–855 mmol H2O2 decomposed min−1 mg−1 protein), peroxidase (1.24–6.35 mmol substrate min−1 mg−1 protein), superoxide dismutase (1236–2963 enzyme U mg−1 protein), glutathione reductase (0.53–2.14 mmol substrate min−1 mg−1 protein), ascorbate peroxidase (1.86–7.04 mmol substrate min−1 mg−1 protein), monodehydroascorbate reducatase (1.11–4.41 mmol substrate min−1 mg−1 protein), dehydroascorbate reducatase (0.34–1.36 mmol substrate min−1 mg−1 protein) was also recorded. Worldwide Abiotic/environmental stresses hamper agricultural production. Enzymatic and non-enzymatic defence system precisely controls this situation. Hence, biochemical evaluation might be an appropriate strategy for identification of suitable germplam to combat the problem of food security in such areas. © 2022, The Author(s), under exclusive licence to Springer Nature B.V.
Evaluation of barnyard millet diversity in central Himalayan region for environmental stress tolerance
(Cambridge University Press, 2017) A.K. Trivedi; L. Arya; S.K. Verma; R.K. Tyagi; A. Hemantaranjan
The mountain ecosystem of the Central Himalayan Region is known for its diversity of crops and their wild relatives. In spite of adverse climatic conditions, this region is endowed with a rich diversity of millets. Hence, the aim of the present study was to explore, collect, conserve and evaluate the diversity of barnyard millet (Echinochloa frumentacea) to find out the extent of diversity available in different traits and the traits responsible for abiotic stress tolerance, and to identify trait-specific accessions for crop improvement and also for the cultivation of millets in the region as well as in other similar agro-ecological regions. A total of 178 accessions were collected and evaluated for a range of morpho-physiological and biochemical traits. Significant variability was noted in days to 50% flowering, days to 80% maturity, 1000 seed weight and yield potential of the germplasm. These traits are considered to be crucial for tailoring new varieties for different agro-climatic conditions. Variations in biochemical traits such as lipid peroxidation (0·552-7·421 nmol malondialdehyde formed/mg protein/h), total glutathione (105·270-423·630 mmol/g fresh weight) and total ascorbate (4·980-9·880 mmol/g fresh weight) content indicate the potential of collected germplasm for abiotic stress tolerance. Principal component analysis also indicated that yield, superoxide dismutase activity, plant height, days to 50% flowering, catalase activity and glutathione content are suitable traits for screening large populations of millet and selection of suitable germplasm for crop improvement and cultivation. Trait-specific accessions identified in the present study could be useful in crop improvement programmes, climate-resilient agriculture and improving food security in areas with limited resources. Copyright © Cambridge University Press 2017.
Genetic variability in proso millet [Panicum miliaceum] germplasm of Central Himalayan Region based on morpho-physiological traits and molecular markers
(Polish Academy of Sciences, Institute of Slavic Studies, 2015) A.K. Trivedi; L. Arya; M. Verma; S.K. Verma; R.K. Tyagi; A. Hemantaranjan
Sixteen representative accessions of proso millet [Panicum miliaceum] having distinct traits of agronomic importance were collected from altitudinal range of 510–2,695 m asl in the Central Himalayan Region (CHR) of India. Considerable diversity was found in morpho-physiological traits viz., leaf length (16.80–32.00 cm), leaf width (1.7–2.1 cm), plant height (57.00–134.00 cm), days to 50 % flowering (34–54), days to 80 % maturity (111–144), and 1,000 seed weight (0.68–1.86 g). Collected accessions have been evaluated for a battery of biochemical parameters viz., chlorophyll, carotenoids, lipid peroxidation, cellular hydrogen peroxide, activity of nitrate reductase, lipoxygenase, catalase, peroxidase, superoxide dismutase along with super oxide free radical formation, glutathione (total, reduced, and oxidized), glutathione reductase, glutathione S-transferase, ascorbate (total, reduced, and oxidized), monodehydroascorbate reductase, and didehydroascorbate reductase. The sets of 12 genic-SSRs (simple sequence repeats), 54 ISSR (inter simple sequence repeats), and 40 SRAP (sequence related amplified polymorphism) markers were used to study the level of genetic diversity, and Nei’s gene diversity value of 0.20 was obtained with both ISSR and SRAP markers. SRAP markers showed higher average number of polymorphic bands, % polymorphism, polymorphic information content (PIC), and Shannon information index compared to ISSR markers; genic-SSRs showed no allelic variation. Cluster analysis shows close groupings of germplasm based on morpho-physiological traits as well as molecular markers. The diverse germplasm identified based on molecular markers with considerable diversity in morpho-physiological traits may be utilized for development of climate resilient cultivars. © 2015, Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.
Molecular profiling of foxtail millet (Setaria italica (L.) P. Beauv) from Central Himalayan Region for genetic variability and nutritional quality
(Cambridge University Press, 2018) A.K. Trivedi; L. Arya; S.K. Verma; R.K. Tyagi; A. Hemantaranjan; M. Verma; V.P. Sharma; D. Saha
Agriculture in the Central Himalayan Region depends on the availability of suitable germplasm as well as natural conditions. Due to extreme weather conditions, food and nutrition security is a major issue for communities inhabiting these remote and inaccessible areas. Millets are common crops grown in these areas. Foxtail millet (Setaria italica (L.) P. Beauv) is an important crop and forms a considerable part of the diet in this region. The aim of the present study was to explore, collect, conserve and evaluate the untapped genetic diversity of foxtail millet at the molecular level and discover variability in their nutritional traits. A total of 30 accessions having unique traits of agronomic importance were collected and molecular profiling was performed. A total of 63 alleles were generated with an average of 2.52 alleles per locus and average expected heterozygosity of 0.37 ± 0.231. Significant genetic variability was revealed through the genetic differentiation (Fst) and gene flow (Nm) values. Structure-based analysis divided whole germplasm into three sub-groups. Rich variability was found in nutritional traits such as dietary fibre in husked grains, carbohydrate, protein, lysine and thiamine content. The collected germplasm may be useful for developing nutritionally rich and agronomically beneficial varieties of foxtail millet and also designing strategies for utilization of unexploited genetic diversity for food and nutrition security in this and other similar agro-ecological regions. © 2018 Cambridge University Press.