Seed Germination and Vigor of Four Philippine Rice Varieties as Influenced by Hydropriming and Storage at Various Durations

Rice seed germination and vigor are vital qualities to improve seedling growth and eventual yield. This study determined the effects of different hydropriming (0, 6, 12, or 18 h) and storage duration (0, 1, 2, and 3 mo) on the seed germination properties and seedling vigor of three irrigated varieties ‘Angelica’, ‘Tubigan 14’, ‘Tubigan 24’, and a rainfed variety ‘Sahod Ulan 9’. The seed quality and germination responses after hydropriming were evaluated every month during storage in ambient conditions (28 ± 2 °C; 85 ± 5% RH) for 3 mo. ‘Sahod Ulan 9’ showed tolerance to low moisture content (MC), higher germination percentage (GP) and germination index (GI), plus faster mean germination time (MGT) and days to radicle emergence (DRE); it also produced seedlings with longer shoots compared to ‘Angelica’, ‘Tubigan 14’, ‘Tubigan 24’. On the other hand, the irrigated varieties showed a higher seed vigor index (SVI) because of their high GP plus longer roots and seedlings. Hydropriming seeds for 6 or 12 h maintained a lower MC, which resulted in higher GP, GI, and SVI; fastest MGT and DRE; and longer shoot, root, and seedling. This study suggests that hydropriming rice seeds of these varieties for 6 h is sufficient to improve germination and vigor. The results suggest that hydropriming rice seeds for 6 h is sufficient to boost the rice germination and vigor of the four rice varieties tested, especially ‘Sahod Ulan 9’. Storage in ambient room conditions is suggested to be limited to only 1 mo after hydropriming as the germination responses decline thereafter. Moreover, the interaction effects of genotype, hydropriming duration, and storage time were found in GP; GI; DRE; root, shoot, and seedling lengths; and SVI.