Drought is a major abiotic stressor that significantly reduces the growth and yield of tomato (Solanum lycopersicum L.). To mitigate its adverse effects, the development and utilization of drought-tolerant cultivars, combined with advanced breeding strategies, offer sustainable solutions. In this study, a total of 157 USDA tomato accessions were evaluated under controlled greenhouse conditions using a randomized complete block design with four replications, incorporating both a water-deficit treatment and a well-watered control group. The results identified ten accessions, including PI 487624, PI 127828, PI 379018, PI 365903, PI 390515, PI 390663, PI 128657, PI 266376, PI 126444, and PI 298933, as drought tolerant, with leaf wilting and leaf rolling scores of less than four. Broad-sense heritability estimates ranged from 50 percent to approximately 58 percent, indicating a moderate genetic influence on drought tolerance. Correlation analysis revealed strong positive associations ranging from 0.50 to 0.99 among leaf wilting, leaf rolling, plant freshness, leaf thickness, and SPAD chlorophyll content, while negative correlations ranging from -0.40 to -0.81 were observed for plant fresh weight, leaf thickness, Quantum yield of Photosystem II (Phi2), and SPAD chlorophyll content traits. These findings provide valuable insights into tomato breeding programs focused on improving drought resilience in elite cultivars. We plan to expand the evaluation to a broader set of accessions and employ genome-wide association studies and genomic prediction to identify single nucleotide polymorphism markers and candidate genes associated with drought tolerance. The integration of genome-wide association studies and genomic prediction will facilitate marker-assisted selection and genomic selection, improving the efficiency of breeding programs aimed at developing drought-resilient tomato cultivars.
