Rice ( Oryza sativa L.), due to its tropical and subtropical origin, is adversely affected by low temperatures below 15°C, restricting growth and yield. During the seedling and vegetative stage, cold stress causes curled leaves, fewer tillers, retarded growth, chlorosis, and necrosis. Due to the significance of this trait, exploring the wealth of genetic resources from a wider pool of germplasm to identify new sources of tolerance will be a crucial step. Toward this goal, we performed a genome‐wide association study (GWAS) on a novel diversity panel of 238 rice accessions using the 7K SNP Cornell‐IR LD Rice (C7AIR) single nucleotide polymorphism (SNP) array. The experiment was conducted in controlled growth conditions, and rice accessions were evaluated for seven traits and four indices, which were recorded at three different time points, that is, before cold treatment, after cold treatment, and post‐recovery phase. A total of 77 significant GWAS‐quantitative trait loci (QTLs) were identified for 21 cold tolerance and related traits of interest. Out of these, 34 were detected after cold stress, and 43 were detected during the post‐recovery phase. A total of 42 QTL regions were significant at false discovery rate (FDR) < 0.001 and −log ₁₀ ( p ‐values) > 5. In addition, 31 novel GWAS‐QTLs, three colocalized GWAS‐QTL hotspots, and eight colocalized GWAS‐QTLs for two traits sharing the same genomic location were also identified. The results of this study may help in further elucidating the molecular mechanisms underlying cold tolerance as well as aid in developing climate‐smart rice varieties for chilling stress conditions.

Plants have evolved a complex, multilayered immune system that integrates molecular recognition, signaling pathways, epigenetic regulation, and small RNA-mediated control. Recent studies have shown that DNA-level regulatory mechanisms, such as RNA-directed DNA methylation (RdDM), histone modifications, and chromatin remodeling, are critical for modulating immune gene expression, allowing for rapid and accurate pathogen-defense responses. The epigenetic landscape not only maintains immunological homeostasis but also promotes stress-responsive transcription via stable chromatin modifications. These changes contribute to immunological priming, a process in which earlier exposure to pathogens or abiotic stress causes a heightened state of preparedness for future encounters. Small RNAs, including siRNAs, miRNAs, and phasiRNAs, are essential for gene silencing before and after transcription, fine-tuning immune responses, and inhibiting negative regulators. These RNA molecules interact closely with chromatin features, influencing histone acetylation/methylation (e.g., H3K4me3, H3K27me3) and guiding DNA methylation patterns. Epigenetically encoded immune memory can be stable across multiple generations, resulting in the transgenerational inheritance of stress resilience. Such memory effects have been observed in rice, tomato, maize, and Arabidopsis. This review summarizes new findings on short RNA biology, chromatin-level immunological control, and epigenetic memory in plant defense. Emerging technologies, such as ATAC-seq (Assay for Transposase-Accessible Chromatin using Sequencing), ChIP-seq (Chromatin Immunoprecipitation followed by Sequencing), bisulfite sequencing, and CRISPR/dCas9-based epigenome editing, are helping researchers comprehend these pathways. These developments hold an opportunity for establishing epigenetic breeding strategies that target the production of non-GMO, stress-resistant crops for sustainable agriculture.

Roots are major contributors to nutrient acquisition, water absorption, and plant anchoring and stability. However, little is known about the root system of industrial hemp ( Cannabis sativa L.), an increasingly important crop worth $16 billion annually. Hemp is commonly cultivated for grain as an oilseed, stalk biomass for fiber and industrial materials, but has also had growing interest for its carbon sequestration potential due to its reported deep rooting profile. The objectives of this research were to (1) phenotype a panel of 46 industrially-relevant hemp genotypes, (2) quantify the phenotypic differences of shoot and root traits through 2D image analysis, (3) and to investigate genotype grouping strategies and gene targets that could be useful for crop improvement. To phenotype the root system architecture of multiple hemp genotypes representative of production hemp, a large format raised-bed was developed in a greenhouse in which hemp was planted in rows. Root and shoot traits varied across genotypes, with a difference of 175% in total root length between the largest and smallest genotype, and heritability values ranging from 0.51 to 0.88 for key root traits. A strong positive correlation was found between root and shoot biomass (R = 0.93) suggests coordinated resource allocation strategies across genotypes. Of the 46 genotypes studied, two genotypes consistently showed the greatest differences across most of the traits analyzed in the panel. A root-to-shoot quadrant framework was applied to classify hemp ideotypes based on biomass allocation and architectural traits. In addition, comparative genomic analysis identified 74 candidate root architecture genes in hemp that are orthologous to known regulators in maize, rice, and Arabidopsis. These findings highlight substantial phenotypic diversity in hemp root systems and provide a foundation for developing genotype grouping strategies and selecting breeding targets for mapping populations.