Seed priming to induce seed germination, seedling growth and enzymatic activity in watermelon

Poor and non-uniform germination, low seedling vigor, and high susceptibility to seed-borne infections constrain successful establishment of watermelon (Citrullus lanatus L.) crops. Seed hydro-priming is a simple and cost-effective pre-sowing technique that enhances seed physiological quality by initiating metabolic processes prior to germination. This study evaluated the effects of seed hydro-priming under different soaking temperatures and post-priming drying conditions on germination, seedling growth, vigor indices, physiological and biochemical attributes, seed health, and field emergence of watermelon cv. Chandraprabhavati. Seeds were hydro-primed in distilled water (1:2, w/v) for 18 h at ambient, 10, 25, and 27 °C, followed by drying under control, shade, 30, 35, and 40 °C conditions in a Completely Randomized Design with three replications. Hydro-priming significantly improved germination, seedling growth, vigor indices, and field emergence compared with non-primed seeds. Germination increased from 75% in control to 96% under, while seedling dry weight increased to 36.92% under seed priming treatment. Electrical conductivity declined markedly, whereas seed leachate pH and total dehydrogenase activity increased, indicating enhanced membrane stability and respiratory metabolism. Seed hydro-priming enhanced seed tolerance to post priming infection from 70% to 5%. Overall, hydro-priming at 25–27 °C followed by drying at 30–35 °C is an effective, low-cost strategy to improve watermelon seed quality and field performance.