Development of an efficient seed dormancy breaking method for African rice ( <i>Oryza glaberrima</i> )

Seed dormancy is a significant factor limiting the conservation, evaluation, distribution and utilisation of African cultivated rice, Oryza glaberrima . In this study, 20 accessions from the AfricaRice genebank were grown at the AfricaRice Mb?? station in C??te d???Ivoire, harvested manually, dried at 15% RH and 15°C, and stored at −20°C for one month before use. Seeds underwent dry heat treatment at 50 or 60°C for 2, 4, 7, 14, 21 or 28 days, or were treated with: 0.5, 1, 1.5 or 2 M KCl; 0.022, 0.112, 0.224 or 0.448 M HNO3; 0.05, 0.1, 0.2, 0.4, or 0.5 M KH2PO4; and 2.89, 5.77 or 14.44 mM gibberellic acid (GA3). Most treatments on intact seeds did not significantly increase germination, except for those treated at 50°C for 21 or 28 days. Dehulled seeds germinated effectively with all treatments except HNO3 solutions. After validating the treatment on 287 O . glaberrima accessions, it was concluded that dry heat treatment at 50°C for 28 days effectively breaks dormancy. This protocol improves germination percentages of O . glaberrima , enhancing its use in various studies and aiding better decision-making in the management of O . glaberrima accessions in genebanks.