Epigenetic Mechanisms in Crop Stress Memory and Their Implications for Agronomy in Nigerian Climate Conditions

This study investigates epigenetic mechanisms underlying crop stress memory in rice and maize under Nigerian climate conditions, developing original insights into the agronomic potential of stress priming for improving crop resilience. Stress memory, the ability of plants to respond more efficiently to recurring stress events due to epigenetic modifications retained from prior stress exposure, represents a potentially transformative but largely unexploited area for agronomic management. In Nigeria's increasingly climate-variable agricultural environments, exploiting stress memory mechanisms could improve crop resilience without genetic modification. This study combines molecular epigenetic analysis using bisulfite sequencing for DNA methylation, chromatin immunoprecipitation for histone modification patterns, and small RNA profiling with agronomic stress priming experiments in rice at NRCRI Umudike and maize at ABU Zaria. Plants are primed with sub-lethal drought, heat, and salinity stress treatments before exposure to severe stress events. Epigenetic modification patterns are correlated with physiological stress response improvements. Field experiments test primed versus non-primed seed performance under water stress conditions. Findings reveal heritable epigenetic modifications associated with improved antioxidant response and stomatal regulation in primed plants, maintaining yield advantages of 18 to 28 percent under severe stress. The epigenetic modifications show partial persistence to F1 generation under high-methylation conditions. Agronomic priming protocols are developed based on optimal priming intensity and timing. The study contributes original epigenetic stress memory data for tropical crops and recommends seed priming protocol integration into Nigerian drought stress management extension guidance.

Keywords: epigenetic mechanisms, stress memory, crop resilience, DNA methylation, Nigeria.