Sorghum Physiology and Adaptation to Abiotic Stresses

Abstract

Sorghum (Sorghum bicolor (L.) Moench) is the world's fifth most important cereal and a staple crop for nations in Sub-Saharan Africa and Asia, with great biomass production potential. In the dry and semi-arid tropics, it may be considered as a source of human food, grain, and pasture for cattle, as well as fuel. Abiotic stress factors such as drought, warmth, salt, and submergence remain key limitations to crop growth and yield as a result of climate change. Although sorghum can resist a variety of conditions such as heat, drought, salt, and floods, in dry and semi-arid areas, this crop is typically damaged by water stress at the post-flowering stage. Drought tolerance is a result of morphological and anatomical characteristics (thick leaf wax, leaf rolling, deep root system, and kranz anatomy), as well as physiological responses such as osmotic adjustment via osmoprotectants, stay green traits, quiescence, and ROS-scavenging enzymes such as catalases (CAT), superoxide dismutase (SOD), peroxidases (POD), and ascorbate peroxida (APX). Drought resistance is enhanced by functional proteins such as aquaporin, late embryogenesis abundant (LEA) proteins, heat shock protein, and regulatory proteins such as protein kinase, various transcription factors such as DREB2, bZIP, and phytohormones such as ABA and ethylene. Drought-tolerant sorghum genotypes contain greater osmolyte, chlorophyll, RWC decrease, leaf rolling, and up-regulation of various enzymes and regulatory proteins. When breeding for drought resistance, it's crucial to understand the various drought tolerance mechanisms in plants. The key to generating abiotic stress-tolerant agricultural plants in the future is to understand the physiological underpinning of crop production, crop responses, and crop adaptability in stress-prone locations under sustainable agriculture.