Reactive oxygen species (ROS) are toxic by-products of aerobic cellular metabolism. However, ROS conduct multiple functions, and specific ROS sources can have beneficial or detrimental effects on plant health. This review explores the complex dynamics of ROS in plant defense mechanisms, focusing on their involvement in basal resistance, hypersensitive response (HR), and systemic acquired resistance (SAR). ROS, including superoxide anion (O²⁻), singlet oxygen (¹O₂), hydroxyl radicals (OH), and hydrogen peroxide (H₂O₂), are generated through various enzymatic pathways. They may serve to inhibit pathogen growth while also activating defense-related gene expression as signaling molecules. Oxidative damage in cells is mainly attributed to excess ROS production. ROS produce metabolic intermediates that are involved in various signaling pathways. The oxidative burst triggered by pathogen recognition initiates hyper-resistance (HR), a localized programmed cell death restricting pathogen spread. Additionally, ROS facilitate the establishment of SAR by inducing systemic signaling networks that enhance resistance across the plant. The interplay between ROS and phytohormones such as jasmonic acid (JA), salicylic acid (SA), and ethylene (ET) further complicates this regulatory framework, underscoring the importance of ROS in orchestrating both local and systemic defense responses. Grasping these mechanisms is essential for creating strategies that enhance plant resilience to biotic stresses.

This study evaluated the yield stability of 14 advanced lentil genotypes alongside two control cultivars (Kimia and Gachsaran) across three growing seasons (2013–2016) and three locations in Iran (Gachsaran, Ilam, and Khoramabad). A randomized complete block design with three replications was employed at each site. The likelihood ratio test confirmed significant effects for environment and genotype‐by‐environment interaction (GEI). A scree test determined that the first three interaction principal components were significant, collectively explaining 79.27% of the total GEI variation. According to the additive main effects and multiplicative interaction 1 (AMMI1) biplot, genotypes G10, G6, G7, G4, and G14 were identified as the most stable, demonstrating minimal contribution to the GEI. Furthermore, the AMMI2‐based biplot (grain yield vs. weighted average absolute scores of BLUP [WAASB]) highlighted genotypes G1, G14, G18, G3, G6, G7, G4, G10, and G9 as possessing high yield and stability. By integrating AMMI and best linear unbiased prediction estimates and applying different weights for seed yield and stability (WAASB), genotypes G2, G9, G12, G16, and G8 were selected as high‐performing and widely stable. Among all, G12 and G2 emerged as the most promising genotypes, combining superior yield with remarkable stability, and are thus recommended as ideal candidates for cultivar release and future breeding programs.