STUDY ON DIVERSITY OF RICE IN NAGALAND AND THEIR SUITABILITY TO CHANGING CLIMATE

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dc.contributor.advisorDas, Ranjan
dc.contributor.authorMerentoshi
dc.date.accessioned2023-10-20T15:57:06Z
dc.date.available2023-10-20T15:57:06Z
dc.date.issued2022
dc.description.abstractThe present investigation was carried out during the year 2018 to 2020 to evaluate the performance of some rice (Oryza sativa L.) genotypes from Nagaland under different CO2 and temperature regimes viz., Treatment I = Field (control), treatment II = (CO2 (550±20ppm) + Temp. of 40 C > ambient) and Treatment III = CO2 (750±20ppm) + Temp. of 60 C > ambient) under fully automated bioreactors with CO2 and temperature control facilities in Stress Physiology Laboratory, Department of Crop Physiology, Assam Agricultural University, Jorhat-13. In the first experiment, 75 rice genotypes collected from different locations of Nagaland were subjected for initial screening for tolerance against elevated CO2 and temperature out of which 7 genotypes were selected for further study on their response mechanism of tolerance by comparing with the national check variety N22. The results revealed that treatment II had a positive impact on the various morpho-physiological parameter viz., plant height, number of leaves, leaf area index, root volume and length, membrane stability index, total leaf chlorophyll content, leaf nitrate reductase activity, proline in all the genotypes whereas a declining trend indicating the deleterious effect of high temperature, at a higher CO2 and temperature in treatment III was observed in all these parameters. Similarly, significant variation in photosynthesis and its related parameters (viz. stomatal conductance, internal CO2, transpiration) affected the photosynthetic rate and their partitioning to root, shoot and reproductive organ under both the treatments as compared to field condition. These factors ultimately contributed to growth efficiency and yield of the plant. Amongst the treatments, significant increase of H2O2, MDA content was recorded in treatment III as compared to treatment III. Kohima Special and N22 recorded lower H2O2 and MDA when compared to other local genotypes. Hence these two genotypes could maintain their plant water status as evidenced by their higher MSI under both the treatments. The maintenance of higher plant water status in Kohima Special and N22 could be attributed to their higher RLWC and increased compatible solutes viz. proline content and non structural carbohydrate contents. Further, studies in tolerance indices indicated that among the tested local genotypes, Kohima Special and Lisem were tolerant whereas Tatza and Tzumma showed to be most susceptible under high temperature. In the molecular analysis, using SCoT molecular markers out of 77 bands amplified, 55 were found to be polymorphic with 68.99 per cent polymorphism. Only four primers SCoT28 and SCoT34 not found to be polymorphic alleles, while remaining 23 SCoT primers showed both polymorphic alleles. Yield and yield attributing characters are governed by all the morphological, physiological and biochemical processes. Among yield parameters, 1000-grain weight, spikelets per panicle and total grain weight per plant were significantly higher due to elevated CO2 at treatment II since the genotypes could maintain a higher photosynthetic rate and had a superior plant defence mechanisms but were significantly decreased under high temperature at treatment III which was negatively influenced by all the processes resulting in decrease in yield and yield attributing characters in all the genotypes.
dc.identifier.urihttps://krishikosh.egranth.ac.in/handle/1/5810199577
dc.language.isoEnglish
dc.publisherAAU, Jorhat
dc.subCrop Physiology
dc.themeSTUDY ON DIVERSITY OF RICE IN NAGALAND AND THEIR SUITABILITY TO CHANGING CLIMATE
dc.these.typePh.D
dc.titleSTUDY ON DIVERSITY OF RICE IN NAGALAND AND THEIR SUITABILITY TO CHANGING CLIMATE
dc.typeThesis
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