Study on diversity of rice in Nagaland and their suitability to changing climate

Abstract

The present investigation was carried out during the year 2018 to 2020 to newlineevaluate the performance of some rice (Oryza sativa L.) genotypes from Nagaland newlineunder different CO2 and temperature regimes viz., Treatment I = Field (control), newlinetreatment II = (CO2 (550±20ppm) + Temp. of 40 C gt ambient) and Treatment III = CO2 newline(750±20ppm) + Temp. of 60 C gt ambient) under fully automated bioreactors with CO2 newlineand temperature control facilities in Stress Physiology Laboratory, Department of Crop newlinePhysiology, Assam Agricultural University, Jorhat-13. In the first experiment, 75 rice newlinegenotypes collected from different locations of Nagaland were subjected for initial newlinescreening for tolerance against elevated CO2 and temperature out of which 7 genotypes newlinewere selected for further study on their response mechanism of tolerance by comparing newlinewith the national check variety N22. The results revealed that treatment II had a positive newlineimpact on the various morpho-physiological parameter viz., plant height, number of newlineleaves, leaf area index, root volume and length, membrane stability index, total leaf newlinechlorophyll content, leaf nitrate reductase activity, proline in all the genotypes whereas newlinea declining trend indicating the deleterious effect of high temperature, at a higher CO2 newlineand temperature in treatment III was observed in all these parameters. Similarly, newlinesignificant variation in photosynthesis and its related parameters (viz. stomatal newlineconductance, internal CO2, transpiration) affected the photosynthetic rate and their newlinepartitioning to root, shoot and reproductive organ under both the treatments as newlinecompared to field condition. These factors ultimately contributed to growth efficiency newlineand yield of the plant. Amongst the treatments, significant increase of H2O2, MDA newlinecontent was recorded in treatment III as compared to treatment III. Kohima Special and newlineN22 recorded lower H2O2 and MDA when compared to other local genotypes...