INFLUENCE OF ABIOTIC STRESSES ON THE PRODUCTION AND SUSTAINABILITY OF RICE CROP.

Rice is a major staple and vital food after wheat, which is consumed globally on a daily basis. However, due to drastic climatic variation, its production is severely impacted by abiotic stresses including drought, salinity, nutrient deficiency, overly submergence, temperature fluctuation and heavy metal stress. Although plants have well-developed defensive mechanisms of stress tolerance, still they are badly affected. According to estimation about 20% of irrigated land is salt affected. Rice is tolerant to salt stress, but their yield losses are higher in low lands than in upper land, mainly due to ionic imbalance and osmotic stress. It is semi-aquatic but prolonged submergence has a lethal effect on plant development and yield. Temperature is another major limitation in rice production, a 1% increase in temperature causes a 10% reduction in yield under dry season. Globally, drought slashes national cereal production by 9-10%, causing up to 28% yield losses during critical growth stages, exacerbated by high-temperature stress. Furthermore, precipitation variations lead to significant production reductions. Heavy metal contamination poses health risks and disrupts ecosystems, with over 53 metals reported in plants, none with prescribed roles. These stresses manifest in various forms, including nutritional disorders, delayed flowering, panicle abnormalities, infertility, and reduced photosynthesis, ultimately culminating in severe yield losses. To address these challenges, diverse management strategies have been deployed. Genomic studies have provided insights into the molecular mechanisms underlying stress tolerance, identifying key genes and pathways involved in stress perception, signal transduction, and stress response regulation. Highthroughput sequencing technologies, such as RNA sequencing and genome-wide association studies (GWAS), have enabled the identification of stress-responsive genes and genetic variations associated with stress tolerance traits. Additionally, functional genomics approaches, including gene editing technologies like CRISPR-Cas9, have facilitated targeted manipulation of stress-related genes to enhance plant resilience against abiotic stresses. Complementary molecular, physiological, biochemical, and agronomic techniques offer promising avenues to bolster stress tolerance and reinvigorate rice production sustainably, minimizing economic losses. [ABSTRACT FROM AUTHOR]