Physiological characterization of rice (Oryza sativa L.) genotypes grown under multiple abiotic stresses
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Date
2021-01
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
Various abiotic stresses limit rice production in the environments, which comprise about 45% of the global rice area. From several years breeders are trying to solve this problem and develop many stress tolerant rice varieties that could be easily accepted by farmers in antagonistic environments. Important stresses include drought, submergence, salinity and cold stress. The present study was aimed at assessing the response of 23 rice genotypes to different levels of mannitol (1% and 2%) as drought stress, salinity using NaCl concentration as salt stress under hydroponic conditions, submergence in 10 cm standing water and cold stress at early seedling stage. The experiment was replicated three times in a Completely Randomized Design. The 23 rice genotypes evaluated for percent germination, root length, dry root weight, shoot length, dry shoot weight, seedling vigour, total chlorophyll content and sodiumpotassium content. Overall reduction was observed in all the morphological (germination percentage, root length, shoot length, root weight, shoot weight and seedling vigour) and physiological parameters (chlorophyll content).Further, six genotypes were selected, two as tolerant, two as moderately tolerant and two as sensitive on the basis of seedling vigour. The sodium content was enhanced under salt stress in the selected genotypes whereas the potassium content was declined in both root and shoot of the seedling. Positive co-relation was observed between total chlorophyll content and seedling vigour of the genotypes with R value = 0.681274. Total proline and protein content of the seeds of selected genotypes was determined which was highest for the tolerant genotypes and lowest for the sensitive one. The interaction between treatments and the genotypes was significant for all the parameters. Several criteria are needed to make a tolerant variety adoptable by the farmers because they seek for adequate grain qualities in the stress tolerant high yielding varieties.