Overcoming physiological dormancy in common buckwheat (Fagopyrum esculentum Moench)

The viability status of every accession stored in a seed bank is essential for effective germplasm conservation, and it is often assessed through germination tests. However, dormancy can hamper this process. Currently, no dormancy-breaking protocols exist for buckwheat (Fagopyrum esculentum Moench) seeds, which exhibit physiological dormancy. In the present study, using phytohormones and chemicals, namely, gibberellic acid (GA(3)), KNO3, and H2O2, we identified effective seed dormancy-breaking protocols. Buckwheat seeds exhibited a high degree of dormancy, with only 21% of seeds having germinated. Treatment with KNO3 (0.1%, 0.2%, or 0.4%) and H2O2 (5, 10, or 20 mM) significantly improved seed germination and the dormancy index, and decreased the time to 50% germination and mean germination time. Furthermore, treatment with 200-ppm GA(3) improved seedling length by 55%. Moreover, treatments with 20-mM-H2O2 and 0.4%-KNO3 improved seed vigor indices by 305% and 260%, respectively. Compared with the control, alpha-amylase activity was higher for all seed treatment groups. The groups treated with both 0.4%-KNO3 and 20-mM-H2O2 had the highest alpha-amylase activity. Thus, treatment with KNO3 (0.1%, 0.2%, or 0.4%) or H2O2 (5, 10, or 20 mM) can be incorporated as a dormancy-breaking protocol for seed testing and germplasm evaluation of buckwheat seeds with physiological seed dormancy.