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20213
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Subject: Plant Physiology × End date: 2021 × Start date: 2021 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Morpho-physiological and biochemical characterization of wheat varieties (Triticum aestivum L.) sown at differential time intervals
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-09) Chandra, Tanvi; Shankhdhar, Deepti
    Wheat (Triticum aestivum L.), a major staple food resource for the world’s population. In present scenario climate changes and elevated temperatures are the big issues that limit its production. An inappropriate timing or delay in sowing is also responsible for sudden elevation in air temperatures during sensitive growth stages of wheat life cycle. Being a winter crop, variability in climates is one of the biggest environmental threats to Indian wheat. The present investigation was carried out to evaluate the effect of elevated temperatures due to variation in sowing timings (November and December) on morpho-physiological and biochemical parameters of 8 varieties of wheat namely; UP2628, HD3086, UP2967, UP2784, UP2526, UP2565, UP2748 and HD3059, conducted during the two consecutive years of Rabi season 2018-19 and 2019-20 in Pantnagar (tarai region). A delay of 30 days in sowing, results elevation in air temperatures; 3.7ºC at tillering, 1.9ºC at heading, 3.7ºC at anthesis and 2.9ºC at grain filling. The morphological, physiological and biochemical parameters, yield and yield related attributes, days taken to complete developmental stages were significantly reduced under December sown wheat varieties as compared to November sown wheat varieties. 3rd internodal distance was found affected by elevated temperatures as compared to 1st and 2nd. On comparing between sensitive growth stages; thermo tolerant traits such as relative water content, membrane stability index, chlorophyll fluorescence, canopy temperatures, chlorophyll pigments and NR activity was significantly decreased during grain filling stage as compared to anthesis. While antioxidants and proline content were found increased as the varieties moves towards grain filling. Quality parameters, carbohydrates, starch and amylopectin were found negatively affected by elevated temperatures while grain nitrogen, storage proteins, amylose content, amylose to amylopectin ratio was positively influenced in December sown wheat varieties. Positive and significant correlation between grain yield and other parameters was found in wheat varieties sown in November while under December sown, relations between the grain yield and other parameters were significantly changed except the correlations among physiological traits, in which non-significant difference was observed between two sowing months.
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    ThesisItemOpen Access
    Chitosan and salicylic acid induced defense response against floral malformation in mango (Mangifera indica L)
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-02) Sudarshna Kumari; Bains, Gurdeep
    Malformation is an ambiguous malady of mango (Mangifera indica L.) with tremendous economic importance through the mango growing regions. Present investigation was carried out at Horticuture Research Station, Patharchatta and Department of plant Physiology, College of Basic Sciences & Humanities, GBPUA&T, Pantnagar during the year 2019 and 2020. The experiment was laid out in Randomized Block Design (RBD) with three replications. Seven different concentrations of chitosan and salicylic acid ( Control, 0.25% CT, 0.50% CT 0.75% CT, 0.20% SA, 0.40%SA and 0.60%SA) were sprayed at three different stages I.e. prior to panicle emergence, pre bloom and full bloom in the month of February to March on two mango cultivars Amrapali (moderately susceptible) and Dashehari ( Moderately resistant). The effect of chitosan and salicylic acid treatment was evaluated with respect to morphological and physio-biochemical parameters. It was observed that chitosan and salicylic acid treatment significantly reduced occurrence of floral malformation as compared to control. Amongst varieties, Amrapali has significantly higher percent malformation than Dashehari. Length of healthy and malformed panicles, leaf area and physiobiochemical characteristics viz. chlorophyll fluoresencem MSI, chlorophyll a, b, total chlorophyll, total phenol , total flavonoid and total protein content, phenylalanine ammonium lyase, chitinase and 1, 3 glucanase activity significantly increased under 0.50% chitosan treatment while, fresh weight of malformed panicle decreased with respect to control. Therefore, chitosan 0.50% was found best for most morphological and physio-biochemial parameters. Highest macro and micro nutrients such as nitrogen, phosphorus and potassium, iron, zinc, copper and manganese content was recurded under 0.75% chitosan treatment. Salicylic acid treatment (0.40%) shows significantly increased proline content, superoxide dismutase, ascorbate peroxidase, catalase and glutathione reductase activity in dose dependent manner while hydrogen peroxidase activity was decreased. Overall findings of the present investigation suggested that pre- treatment of chitosan or salicylic acid at both 0.50% chitosan and 0.40% salicylic acid could help in maintaining vital physio-biochemical processes and induced defence response by eliminating the active oxygen species and strengthening plant defence mechanism. Chitinase and 1, 3 glucanase is an important and reliable screening markers which should be utilized for developing malformation resistant or less susceptible mango cultivars. This study will help the researcher to uncover the critical areas of chitosan on mango characteristics and malformation resistance. Therefore, in future chitosan can be used to induce the resistance against mango malformation.
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    ThesisItemOpen Access
    Elucidation of the tolerance mechanism of different genotypes of rice (Oryza sativa L.) for drought, salinity and submergence stress
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-02) Maurya, Kalpana; Atul Kumar
    Rice (Oryza sativa L.) is a staple food for more than half of the world’s population. A major environmental factor that limits growth and yield of rice is abiotic stress. This problem has become more and more serious as multiple stresses such as drought, salinity and submergence often occur simultaneously due to global climate changes. The present investigation was conducted in laboratory, fields and pot experiment in the rainy seasons, 2014 and 2015 at the G.B. Pant University of Agriculture and Technology, Pantnagar in fifteen rice genotypes namely, IET 24093, IET 24098, IET 24099, IET 24100, IET 24102, IET 24103, IET 24104, IET 24111, PHY 4, PHY 5, PHY 6, PHY 7, PHY 8, AC 39416 A, SM 686 were used in the study. In laboratory experiments, the effect of drought, salinity and submergence stresses on seed germination and seedling growth was evaluated. A field experiment was also conducted to evaluate the field performance of rice genotypes. Further a pot experiment was conducted to study the effect of drought stress on growth, yield, morphological and biochemical parameters of rice genotypes. Studies under laboratory condition revealed that shoot length, root length and seedling vigour of all the rice genotypes decreases under drought salinity and submergence stress. Among the genotypes AC 39416A, SM 686, PHY 8 were tolerant to drought salinity and submergence. Field experiment revealed that genotype PHY 7, PHY 8, AC 39416A performed best in terms of grain yield while IET 24093 recorded lower grain yield. A pot experiment revealed AC 39416A genotype tolerant while IET 24098 susceptible in terms of morphological, physiological and biochemical parameter i.e. grain yield, seedling vigour, more proline accumulation, lipid peroxidation and super oxide dismutase activity. Overall results revealed that these genotypes have tolerance mechanism due to their genotypic differences in the rice genotypes.