Assessment of variability in acquired thermotolerance in rice (Oryzasativa L.) through temperature induction response (TIR) technique

Abstract

High temperature stress is a major concern for crop production worldwide because it greatly affects the growth, development and productivity of plants. Plant response and adaptation to elevated temperature and the mechanisms underlying the development of heat tolerance, to be better understood for important agricultural crops. The unfavourable effects of heat stress can be mitigated by developing crop plants with improved thermotolerance using an assortment of genetic approaches. Acquiring thermotolearnce is a lively progression by which considerable amount of plants resources are diverted to structural and functional maintenance to escape damaged caused by heat stress. The present study was conducted at Department of Plant Physiology, College of Agriculture, Indira Gandhi Krishi Vishwavidyalaya, Raipur (C.G.)during summer 2015 and 2016to adapt a novel temperature induction response (TIR) technique for identifying highly thermotolerance rice genotypes which can be used as donor source for developing high temperature tolerant rice genotypes to withstand future temperature rise, The screening observations for heat tolerance were recorded on five randomly selected plants in each plot on 430 rice accessions. Therefore, screening revealed that 93 accessions performed well for heat tolerance. The most of genotypes significant in quantitative characters but spikelet fertility was a more powerful indicator for screening at the reproductive stage than other stages. The high genotypic and phenotypic coefficient of variation was recorded for unfilled grains and total number of grains per panicle under high temperature stress during both summer seasons. Thus, this approach forms one of the potential screening tool techniques to evaluate genetic variability for intrinsic stress tolerance.