kR Dose Research Articles

Post-implantation defects in heavy ion implanted monocrystalline ZnO

Monocrystalline ZnO samples were implanted with Co (transition metal) and with Ar and Kr noble gas ions, with energies and doses leading to comparable damage in the host lattice as regards its extension and magnitude. Structural properties of the implanted ZnO were investigated by channeled Rutherford Backscattering Spectrometry (cRBS), aided with calculations using McChasy code. It was shown that the damage produced by implantation does not reach an amorphization level in all cases and is produced deeper in the crystal in comparison with theoretical predictions. The range and magnitude of damaged region are comparable in all cases of ion implantation.

Effect of gamma ray irradiation and ethyl methane sulphonate onin vitromutagenesis ofCitrullus colocynthis(L.) Schrad

In the present study in vitro mutagenesis was used to study the effect of gamma irradiation and EMS on callus induction, morphogenesis and production of multiple shoots from different explants of Citrullus colocynthis (L.) Schrad. Gamma radiations (5 kR to 20 kR) and certain chemicals have been effected on plant growth developments and changes of biochemical metabolisms in plants. Murashige and Skoog (MS) medium containing with auxins such as NAA, IAA, 2,4-D (0.5 ~ 2.0 mg/l), cytokinines BAP, kn TDZ, (0.5 ~ 2.5 mg/l), L-Glutamic acid (1 ~ 2 mg/l) and Coconut milk (10 ~ 20%). After 5 weeks on induction media, explants and callus (EC) were exposed to 5 kR, 10 kR, 15 kR and 20kR, of gamma radiation and treated with 1, 2, 3, 4 and 5 mM ethyl methane sulphonate (EMS) for 30 min. The highest percentage of callusing was observed (70%) stem irradiated with 5 kR and significantly decrease in fresh and dry weight of callus in the below 4 kR doses and above 20 kR doses, there was a progressive decrease in the fresh weight and dry weights when compared to control callus. Maximum percentage of plantlet regeneration (59%) was induced from callus exposed to 15 kR gamma irradiation on MS media fortified with 2.0 mg/l 2,4-D + 2.0 mg/l BAP + 2.0 mg/l L-glutamic acid. Increase in gamma irradiation dose above 15 kR and 5 mM EMS reduced regeneration capacity of callus. Doses higher than 20 kR and 7 mM EMS was lethal to micropropagated plants of Citurullus colocynthis.

Effect of Gamma Rays on Sophora davidii and Detection of DNA Polymorphism through ISSR Marker.

Sophora davidii (Franch.) Kom. ex Pavol is an important medicinal plant and a feeding scrub with ecological value. The effects of different gamma irradiation doses (20–140 Kr) on seed germination and seedling morphology were investigated in S. davidii, and intersimple sequence repeat (ISSR) markers were used to identify the DNA polymorphism among mutants. Significant variations were observed for seed germination, stem diameter, and number of branches per plant. The improved agronomic traits, such as stem diameter and number of branches per plant, were recorded at 80 Kr dose and 20 Kr dose for seed germination. ISSR analysis generated in total 183 scorable fragments, of which 94 (51.37%) were polymorphic. The percentage of polymorphism ranged from 14.29 to 93.33 with an average of 45.69%. Jaccard's coefficients of dissimilarity varied from 0.6885 to 1.000, indicative of the level of genetic variation among the mutants. The constructed dendrogram grouped the entities into five clusters. Consequently, it was concluded that gamma rays irradiation of seeds generates a sufficient number of induced mutations and that ISSR analysis offered a useful molecular marker for the identification of mutants.

Determination of lethal dose for gamma rays induced mutagenesis in different cultivars of dahlia

High aesthetic and economic importance of dahlia stimulates breeders for the development of new cultivars. To determine the lethal dose (LD50) of gamma rays in different cultivars of dahlia, an experiment was conducted at MFC, GB Pant University of Agriculture and Technology, Pantnagar. Rooted cuttings of three dahlia cultivars viz., Jyotsana, Agni and Glory of India were exposed to acute (60Co) gamma ray irradiation at 0.0 (Control), 1.0, 1.5, 2.0, 2.5 and 3.0kR to determine the lethal doselevel. Probit analysis for extrapolated LD50 in different cultivars of dahlia for mortality was 2.07, 1.91, and 1.87 kR for Jyotsana, Agni and Glory of India, respectively indicating the higher sensitivity for cultivar Glory of India. There was direct correlation between dose of gamma irradiation and mortality of cuttings. Maximum mortality (47.00%) was observed at 3.0 kR while, minimum (10.00%) was observed at 1.0 kR dose of gamma rays treatment. Different cultivars also exhibited significant differences for mortality percentage by gamma rays irradiation. The LD50 values for maximum survival percentage of cuttings can be fixed at 2.07, 1.91 and 1.87 kR of gamma rays irradiation for cvs. Jyotsana, Agni and Glory of India, respectively.

English

Abelmoschus esculentus (okra) is a popular health food because of its high fiber, vitamin C and folate content. It is also rich in antioxidants, a good source of calcium and potassium. Three varieties of okra: Jokoso, NHAe47-4 and Beru (a local variety) were irradiated with 20, 40, 60, 80 and 100 kr doses of gamma rays then soaked in 2.0 mM and 3.0 Mm of Sodium azide for 2h with the aim of determining the effects of the combined mutagens on their morphology. There were significant differences between the control and the treated seeds used in their germination, seedling survival, seeding length, survival to maturity and height at maturity. The effective concentrations and doses of combined mutagens for Beru and NHAe47-4 varieties were: 2.0 mM + 20 kr, 2.0 mM + 40 kr, and 2.0 mM + 60 kr and 3.0 mM + 20 kr, 3.0 mM + 40 kr, and 3.0 mM + 60 kr) while the effective concentrations and doses for Jokoso variety were: 2.0 mM + 20 kr, 2.0 mM 40 kr 2.0 mM 60 kr and 3.0 mM + 20 kr only. Jokoso variety was worse affected than any other. Sodium azide and gamma rays can be used for inducing mutation that will produce genetic variability in Okra. Key words: Abelmoschus esculentus, germination, genetic variability.

Morphological changes and induced mutagenesis in gladiolus varieties through gamma irradiation

An experiment was conducted for 3 years (2011-12 to 2013-14) at Varanasi to find out influence of various gamma doses, i.e. 1.5, 2.5, 3.5, 4.5 and 5.5 kR along with untreated (control) in different varieties of gladiolus, viz. Aldebaran, Jyotsana, Legend, Praha, Punjab Dawn, Pusa Kiran and Tiger Flame. During 1st and 2nd years various parameters were observed and data were pooled for statistical analysis, whereas during 3rd year stability of characters was observed among mutants. The experiment was laid out in randomized block design with 5 replications. Maximum leaf area was observed with control plants followed by 1.5 kR, 2.5 kR, 3.5 kR, 4.5 kR and 5.5 kR treatments. Narrower and short leaves were observed as gamma doses increased. Maximum length of spike at 1st floret opening was recorded with control followed by 1.5, 2.5, 3.5, 4.5 and 5.5 kR. There was no significant difference between 1.5 kR and 2.5 kR treatments on length of spike at 1st floret opening. Gamma dose at 2.5 kR registered durability of 1st floret followed by 1.5 kR, control, 3.5 kR, 4.5 kR and 5.5 kR treatments. No significant difference was observed between 2.5 kR and 1.5 kR treatments. Control plants gave maximum diameter of 3rd floret followed by 1.5 kR, 2.5 kR, 3.5 kR, 4.5 kR and 5.5 kR. Among varieties, cv. Jyotsana registered maximum length of spike, cv. Punjab Dawn resulted in maximum durability of floret and cv. Tiger Flame registered maximum diameter of 3rd floret. Interaction of = gamma doses and varieties were also found significant in all the characters studied. Various morphological changes were observed on gladiolus varieties in cv. Jyotsana, Legend and Praha at 1.5 to 3.5 kR doses of gamma. A mutant was identified from variety Tiger Flame at 4.5 kR of gamma irradiation. This mutant was observed during 1st and 2nd years. It was a stable mutant, hence, isolated during 3rd year. Flower colour of mutant was different to the parent. Lower petals of mutant were found of yellow colour. It looks very attractive.

Dose-dependent isotherm of Kr adsorption on heterogeneous bundles of closed single-walled carbon nanotubes

We present 77 K isotherms of krypton adsorption on bundles of closed highly-pure HiPco single-walled carbon nanotubes (SWCNTs). Two volumetric adsorption protocols were used, one with an increasing Kr dose per injection (IAD), one with a constant dose (CAD). Detailed microstructural examination showed that the SWCNTs combine into small bundles (of 25-30 SWCNTs) which are heterogeneous in diameter with a consequential range of interstitial channel (IC) shapes and sizes. The IC-sites are the subnanoscaled pores with alternating enlargements and constrictions along the tube axes. This results in adsorption dosing (AD) dependent characteristics of the low-pressure region of the isotherm. In the IAD protocol the switch-back behavior of the isotherm stemmed from metastable adsorption. Using the CAD protocol, different branches are observed. Well-pronounced substeps were established which we interpret as corresponding to the formation of various phases of confined Kr with different atoms arrangement. The height of a given substep obtained in different measurements depends on the AD value which can strongly influence the population of the site. Some substeps existing only for certain values of AD suggests the existence of a certain selectivity or of a preferential phase formation according to this value.

Studies on gamma ray induced mutants in gladiolus

An experiment was conducted for 2 years (2011-12 to 2012-13) at Varanasi to find out the influence of various gamma rays doses, i e 1.5, 2.5, 3.5, 4.5 and 5.5 kr along with untreated (control) in different varieties of gladiolus, viz. Aldebaran, Jyotsna, Legend, Praha, Punjab Dawn, Pusa Kiran and Tiger Flame. Higher dose of gamma irradiation (5.5 kr) resulted in minimum sprouting. Maximum sprouting percentage was recorded with control followed by 1.5 kr, 2.5 kr, 3.5 kr, 4.5 kr and 5.5 kr. Gamma ray doses at 3.5 kr, 4.5 kr and 5.5 kr found were lethal in case of three varieties, i e Aldebaran, Legend and Praha and failed to produce any spike during 1st year. Early spike emergence (74.37 days) was recorded with 1.5 kr dose of gamma irradiation. Late opening of 1st floret (94.00 days) was observed with 2.5 kr of gamma dose. Flower opening was not observed at higher doses, i e 3.5 kr, 4.5 kr and 5.5 kr in cv. Pusa Kiran during 2nd year. Maximum number of flowers/spike was recorded with control which was at par with lower dose of gamma irradiation (1.5 kr). Gamma dose at 2.5 kr exhibited maximum durability of 2nd and 3rd florets. Maximum length of spike at the last floret opening was noticed in control (74.48 cm) followed by 1.5 kr, 2.5 kr, 3.5 kr, 4.5 kr and 5.5 kr. During both years 2.5 kr resulted in maximum duration of flowering. Treatment 4.5 kr resulted in abnormal plant growth, bunched spike in some plants of cv. Pusa Kiran. A mutant having creamish white colour was found at 2.5 kr in one plant of cv. Jyotsna. A colour mutant was observed in cv. Tiger Flame. This colour mutant produced yellow coloured florets at 3.5 kr treatment. One mutant had been found in cv. Punjab Dawn at 2.5 kr treatment. Flowers were white in colour, whereas, flower colour of parent variety Punjab Dawn is pink. Colour of the flowers was white during VM1 and it was found stable in VM2.

Effect of gamma irradiation on morphological changes, flowering and induced mutants in gladiolus

Investigation was carried out for 3 years (2011–12, 2012–13 and 2013–14). Gamma doses, i.e., 0.0, 1.5, 2.5, 3.5, 4.5 and 5.5 kR were applied on seven gladiolus varieties (Aldebaran, Jyotsana, Legend, Praha, Punjab Dawn, Pusa Kiran and Tiger Flame). Maximum plant height and leaf area index were registered with control which was at par with 1.5 kR irradiation. Early colour show of floret petal was recorded with 5.5 kR and it was exhibited late with control. Lower dose of gamma irradiation (1.5 kR) exhibited the maximum diameter of 1st floret. Maximum spike length was recorded with control and it was at par with 1.5 kR. Various morphological changes were observed on the plants and flowers in Pusa Kiran, Jyotsana and Praha varieties at 2.5 and 4.5 kR gamma irradiation doses. A mutant was identified during vM1 and vM2 in variety Tiger Flame at 4.5 kR dose of gamma irradiation. This mutant was isolated during vM3 having yellow colour lower petals, whereas in parent genotype petals colour was orange. Flowers of mutant are arranged densely on the spike due to short internodal length, resulting in attractive look.

English

Genetic variability in Jatropha curcas was induced by different doses (5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 kR) of gamma-rays. Gamma radiation induced earliness in flowering and the plants set flowers earlier than that of control, which took longer duration of 327 days for flowering. The improved reproductive and yield parameters such as days taken to first flowering, flowering population, male to female ratio and seed yield per plant were recorded in 25 kR dose and seed germination in 5 and 10 kR treated seeds. Molecular characterization of induced mutants (M1 generation) with 47 Random amplified polymorphic DNA (RAPD) primers showed 65.27% polymorphism. The variability created by gamma rays ranged from 9 to 28%. The 50 kR mutant was found to be the most diverse from control followed by 25 kR mutant. Thus, this integrated approach can be used for carrying out the mutation-assisted breeding and subsequent selection of desired mutants using molecular markers in J. curcas.   Key words: Jatropha curcas, random amplified polymorphic DNA (RAPD), gamma-rays, induced mutagenesis.

English

Rapeseed-mustard crops in general, show low average productivity due to the prevalence of various biotic and abiotic stresses. Among biotic stresses, diseases such as white rust and Alternaria blight are the major contributing factors. Alternaria blight caused by Alternaria brassicae has been reported to cause variable losses in yield. The present study aimed to induce mutations for Alternaria blight resistance/tolerance in Ethiopian mustard and screen the induced mutants through in vivo (detached leaf method) as well as in vitro (cultural filtrate) methods for disease resistance/tolerance in different generations. About 46 mutants in M2 generation were isolated which showed segregation for A. brassicae tolerance. Only 10 mutants showed very less sporulation intensity along with less halo and concentric ring diameter. These mutants were further evaluated under natural field conditions at Kangra to confirm their reaction. Out of these, only two mutants viz., P (4)2 in 80 kR and P13 in 100 kR doses were observed to be moderately resistant/tolerant against A. brassicae (PDI < 25.0%, scale 2). The behaviour of theses mutants was further confirmed by in vitro studies. Both mutants showed pale yellow to light brown and fragile callus in all three concentrations of fungal filtrate. Both fresh and dry weights of calli were maximum in 80 and 100 kR dose-explants in M0 and M4 generations as compared to 50, 60, 70, 90, and 110 kR dose-explants in M0 generation. The in vitro selection could effectively be used to screen genotypes right in M0 generation itself as 80 and 100 kR doses exhibited moderate resistance/tolerance against Alternaria blight both in M0 and M4 generations. Hence, in vitro selection method can be used as an efficient tool for screening mutants dose-wise in initial generations, saving time and laborious field work required to screen mutants in vivo for a minimum of 3 to 4 generations. Key words: Alternaria blight, brassica, callus, cultural filtrate, in vivo, in vitro, resistance.

Variability of pollen viability in the flowers and inflorescences of the China aster (Callistephus chinensis Nees) caused by gamma rays in the M1 and M2 generations

The influence of gamma rays (within range 3-12 kR) on the variations of pollen viability was investigated in four varieties of &lt;i&gt;Callistephus chinensis&lt;/i&gt; Nees in the M&lt;sub&gt;1&lt;/sub&gt; and M&lt;sub&gt;2&lt;/sub&gt; generations. The variability, both in generation M&lt;sub&gt;1&lt;/sub&gt;and M&lt;sub&gt;2&lt;/sub&gt; of the studied character between the plants and flowers within the inflorescence proved to be dependent on the radiation dose and was as a rule higher in populations exposed to radiation than in the control ones. These regularities, however were not equal in the tested varieties. The total variance of pollen viability in the M&lt;sub&gt;2&lt;/sub&gt; generation was in general lower as compared with that of the M&lt;sub&gt;1&lt;/sub&gt; generation, whereas the particular variance components showed an extremal dependence (minimum after a 3 kR dose) on the radiation dose.

IV. Effect of &lt;sup&gt;60&lt;/sup&gt;Co gamma rays on survival rate of China aster plants (Callistephus chinensis Nees) in M1 generations - under field conditions

Studies were undertaken on the effect of different doses of gamma radiation on survival rate of plants (germinated from irradiated seeds) for 5 China aster varieties specified at florescence time. During their growth under field conditions (from planting time to blooming) lethal effect of the radiation occurred in plants of all varieties and its level depended on dose and variety. Effect of 3 kR and 6 kR doses differed depending on variety and was not always harmful, but following irradiation with doses exceeding 6 kR a considerable decrease in survival rate was observed. Radioresistance of studied varieties - measured both: by LD&lt;sub&gt;50&lt;/sub&gt; and LD&lt;sub&gt;l00&lt;/sub&gt; - differed; depending on variety, LD&lt;sub&gt;50 &lt;/sub&gt;and LD&lt;sub&gt;l00&lt;/sub&gt; values fluctuated: from 6 to 9 kR and 12 to 15 kR respectively.

Induced mutagenesis in Jatropha curcas L. using gamma rays and detection of DNA polymorphism through RAPD marker

The aim of this study is to examine the effect of different doses (control, 5, 10, 15, 20 and 25 Kr) of gamma irradiation on seed germination, flowering, fruit and seed traits of Jatropha curcas and to identify DNA polymorphism among the mutants through a Randomly Amplified Polymorphic DNA (RAPD) marker analysis. The improved agronomic traits such as flowering, fruits and seeds were recorded in 5 Kr dose and seed germination percentage in 10 Kr dose treated plants, while corresponding parameters were reduced significantly ( P > 0.05) in 25 Kr dose gamma rays treated plants when compared to that of control. All the twenty-three random primers used except six primers, namely OPAW16, OPAK07, OPAK15, OPS01, OPAK20 and OPAL09 were showed polymorphic bands. The primers: OPAW16, OPAK07, OPAK15, OPS01, OPAK20 and OPAL09 produced only one band each across the six mutants, while the primers: OPU13, OPAB 15, OPF01 and OPAB11 were produced with maximum number of bands (8). The number of amplicons varied from 1 to 8 with an average of 3.9 bands, of which 2.3 were polymorphic. The percentage of polymorphism per primer ranged from 0 to 100 with an average of 55.16%. The Jaccard's coefficients of dissimilarity varied from 0.324 to 0.397, indicative of the level of genetic variation among the mutants studied. The maximum dissimilarity value (0.397) was observed in 5 Kr mutant while the minimum value (0.250) was observed in 20 Kr mutant when compared to that of control. In a dendrogram constructed based on genetic similarity coefficients, the mutants were grouped into three main clusters; (a) control, 10, 15 and 20 Kr dose mutants clustered together, (b) 25 Kr dose grouped alone, (c) 5 Kr dose also grouped alone. The mutants showing the differences in morphological traits showed DNA polymorphism in PCR profile amplified by RAPD marker. It is concluded that DNA polymorphism detected by RAPD analysis offered a useful molecular marker for the identification of mutants in gamma radiation treated plants.

Induction of Mutation in Rough Lemon (Citrus jambhiri Lush.) Using Gamma Rays

The present investigation was carried out to study variability induced by gamma rays with respect to vegetative characters and LD50 dose in Rough lemon. Rough lemon seeds were gamma irradiated at doses of 0, 4, 6 and 8 kr along with control. Seed germination decreased with increasing dose of gamma radiation. Seedling height and leaf size also decreased with increasing dose of gamma radiation, whereas, apical branching, number of branches/seedling, number of variegated / albino seedlings and number of leaves increased with increasing dose of gamma radiation. Maximum variability for seedling height, number of leaves, leaf size, colour, internode length, and per cent apical branching was observed at two months from sowing in seeds treated with 8 kr dose of gamma radiation. Variability for all characters was, however, found to be minimum in the control.

Cytogenetic Effects of Gamma Rays on Indica Rice Radha-4

The present study was conducted to understand the effects of different doses of radiations by gamma rays of Co60 on cytogenetics of indica rice, Radha-4 at the Central Lab, Institute of Agriculture and Animal Science, Rampur, Nepal. The immature PMC of M1 generation plants were analyzed performing the usual smearing and squashing technique. Radiation had a significant effect causing different types of cytogenetic aberrations, such as univalent and multivalent association of chromosomes, chromatin-bridges, laggards, fragments, stickiness, and multinucleated cells. An increasing number of aberrant cells with increasing dose of radiation was identified. The greatest share of aberration was identified due to multivalent association as a result of translocation followed by bridges and laggards, and the least effect for the stickiness of the chromosomes. Finally, 35 KR doses of gamma rays was the most potent dose inducing cytogenetic aberrations in meiotic pollen mother cell of rice compared to other dose spectrum.J. Inst. Agric. Anim. Sci. 27:25-36 (2006)

GAMMA RAY - INDUCED MITOTIC ABNORMALITIES IN Helianthus annuus L. VARIETY EKIZ 1 / LOS RAYOS DE GAMMA CAUSA ANORMALIDADES MITOTICAS EN Helianthus annuus L. VARIEDAD DE EKIZ 1 / LES ANORMALITÉS MITOTIQUES CHARGÉÉS DES RAYONS GAMMA

SUMMARYIn this study, mitotic effects of gamma rays on Ekiz 1 variety belonging to Helianthus annuus L. (2n= 34) in the M0 (first irradiated seeds), M1 and M2 generations have been investigated. Seeds (M0) were irradiated with gamma rays at 10, 20, 30, 40 and 50 kR doses. Percentage of total abnormalities in the M0, M1 and M2 generations increased parallel to the increasing dose of radiation. These abnormalites have been observed as C-metaphase, chromosome stickiness, laggards and bridges with or without fragment. Mitotic index (M.I.) in the M0, M1 and M2 generations has decreased parallel to the dose increase. When the generations are compared, both the amounts of decrease in mitotic index and in the percentage of mitotic abnormalities were mostly observed in M0.

MEIOTIC STUDIES IN THE M2 GENERATION OF Helianthus annuus L. VARIETY EKIZ 1 AFTER GAMMA IRRADIATION / LOS ESTUDIOS EN LA GENERACION DE Helianthus annuus L. LA VARIEDAD EKIZ 1 DESPUES DE LA IRRADIACION DE LA GAMMA / APRÉS LE RAYONNEMENT DES GAMMA DANS LA GÉNÉRATION M2 DE LA VARIÉTÉ EKIZ 1 (Helianthus annuus L.)

SUMMARYThe effect of gamma rays on meiosis in the M2 generation has been studied in sunflower (Helianthus annuus L.) variety Ekiz 1. Seeds were irradiated with gamma rays at 10, 20, 30, 40 and 50 kR doses. Radiation induced meotic abnormalities. The chromosomal aberrations included univalents, multivalents and stickiness at diakinesis, laggards and stickiness at metaphase I, bridges and laggards at anaphase and telophase I-II, micronuclei at telophase II. The percentage frequencies of anomalies increased generally with the increasing dose of radiation.

Cytogenetic Effects of Gamma Rays and Ethyl Methane Sulphonate in Chilli Pepper (Capsicum annuum L.).

Seeds of Capsicum annuum L. var. G-4 Bhagyalakshmi were subjected to 15, 25, 35 kR doses of gamma ray, and 0.8% and 1% ethyl methane sulphonate (EMS). Effects of mutagenic treatments of meiosis viz. chromosomal anamolies, pollen sterility, seed sterility and survival percentage in M2 generation have been reported. EMS was found more effective in inducing meiotic irregularities than gamma ray treatment. A dose dependent increase in meiotic anomalies was obtained with all the mutagenic treatments.

Plant height reduction in populations of triticale (X triticosecale Wittmack) by induced mutations and artificial crosses

Induced mutations by gamma radiation (0, 5, 10, 20 and 40 kR doses) and reciprocal crosses were tested as mechanisms of enhancing genetic variability for plant height in two triticale cultivars, BR4 and EMBRAPA18. The reciprocal crosses and all doses of radiation showed similar increase in genetic amplitude for this trait, being suitable for increasing variability in breeding programs. Genotypes showed different responses as the gamma ray doses were increased, expressing shorter plant height. The decision of using induced mutations or artificial crosses depends on the resources available and the selection method to be used