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Subject: Basic Sciences × End date: 2017 ×
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    ThesisItemOpen Access
    Studies on mutagenic effects of gamma radiation and ethyl methane sulphonate on qualitative and quantitative traits in Tagetes patula L. (French Marigold)
    (G.B. Pant University of Agriculture and Technology, Pantnagar (Uttarakhand), 2017-01) Tripti; Chaturvedi, Preeti
    The present investigation was conducted at Medicinal Plants Research and Development Centre, G.B. Pant University of Agriculture and Technology, Pantnagar during 2014-15 and 2015-16. The experiment was laid out in Factorial Randomized Block Design (FRBD) with three replications and thirty treatment combinations, comprising of five varieties of T. patula L. viz., Safari Red, Guljafri Orange, Bonanza, Guljafri Yellow and Nana Patula Yellow, treated with five different dosage of gamma rays (2.5, 10.0, 15.0, 20.0 and 25.0 kR) and five different concentrations (0.25, 0.50, 0.75, 1.0, 1.25%) of Ethyl methane sulphonate (EMS) separately. Seed biology, vegetative, qualitative and quantitative floral characters in relation to above mentioned treatments were found to be influenced significantly by different doses/concentrations of gamma irradiation and EMS. Among physical and chemical mutagens, gamma radiations were more commodious in developing assorted beneficial traits. Data analysis of various biological parameters during M1, M2 and M3 generations showed that the impact of the mutagen did not cease in M1 but continued to effect even in M2 and M3 generations. Seeds irradiated with lower doses reflected a significant stimulatory effect on plant height, number of days for flower bud initiation and days to full bloom. It is hypothesized that low doses/concentrations of physical and chemical mutagens has the potential in modulating several vegetative and floral components which helps the plant to overcome daily stresses during growth conditions by increasing the antioxidative ability of cells and by changing the hormonal signaling in plants. Gamma irradiation also enhanced the accumulation of carotenoids in plants to protect chlorophyll from photooxidative damage under stress conditions by neutralizing the effect of singlet oxygen species. Not only this, mutagens caused difference in relative proportions of different floral pigments and markedly altered the flower colour resulting in different colour mutants of T. patula L. On the basis of flower colour variation, different mutants were documented, tagged and classified. Mutants that were consistently present in all the three generations were identified and assesement of their bioactive compounds in comparison to control was done through Gas Chromatography – Mass Spectrometry (GC-MS). Two screened flower colour mutants (NY5 and BN1) were identified from T. patula L. var. Nana Patula Yellow and T. patula L. var. Bonanza, respectively which were found persistent in M1, M2 and M3 generations. GC-MS analysis of the plants treated with gamma radiations also showed some novel and greater diversity of metabolites having important biological activities. Henceforth, gamma rays can be employed as an elicitor in inducing desired metabolic responses in plants. Concentration of lutein (carotenoid) which is highly useful in the food and pharmaceutical industries, varied in greater extent among the mutants belonging to the same variety. Thus, congenial correlation was found between lutein and different shades of colour in mutants. The results clearly recommend low doses of mutagens for stimulation in certain vegetative characters, and comparatively higher doses for qualitative and quantitative floral characters variability. However, further work is required on pigment proteiomics and metabolomics to elaborately explain the response of plant to different doses of physical and chemical mutagens. Efforts in future can be directed to metabolically engineer the plants for the production of lutein and other bioactive compounds thereby providing an opportunity to improve and stabilize desired qualitative and quantitative traits.