Evaluation of Seed Priming and Vernalization on Radish (Raphanus Sativus) Production

Radish (Raphanus sativus L.) seed production in the tropics is limited by poor, uneven crop establishment and by the plant’s need for cold to trigger flowering. This study tested how seed priming and seed vernalization affect bolting, flowering and seed yield in radish. It was conducted at the University of Southern Mindanao, Kabacan, Cotabato, Philippines, from April to July 2025. The design was a two-factor factorial experiment in a Randomized Complete Block Design with three replications. Factor A was seed treatment: non-primed seeds, or seeds primed by a 12-hour soak and then shade-dried. Factor B was vernalization at 5 °C for 0, 24, 72, 168 or 336 hours. An open-pollinated variety was grown in polyethylene bags without fertilizer or pesticides. The data were analyzed by ANOVA and the Least Significant Difference test. Longer vernalization significantly shortened the time to bolting and flowering in both primed and non-primed seeds. The 168-hour and 336-hour treatments bolted about 62 days after sowing, compared with 64–66 days for the control, and flowered about 81–83 days after sowing, compared with 84–85 days. Vernalization also significantly increased the number of siliquae. The highest counts were 113.24 per plant in primed seeds at 168 hours and 103.82 in non-primed seeds at 168 hours, compared with controls of 85.47 and 74.15. Seed weight rose significantly with vernalization only in primed seeds, from 2.13 g in the control to 4.73 g at 336 hours. In non-primed seeds the differences in seed weight were not significant. Primed seeds generally flowered earlier and produced more siliquae than non-primed seeds. Overall, combining seed priming with 7–14 days of seed vernalization is a simple, low-cost way to speed up reproductive development and raise radish seed yield under lowland tropical conditions.