Abstract
This study evaluated the effect of deep freezing on germination and seedling vigor of bitter apple seeds. Mature bitter apple fruits were collected from Madinah and Riyadh regions, Saudi Arabia. Seed lots extracted from each location were sequentially numbered. Moisture content percentage was measured for all seed lots before and after cryopreservation. Seeds were packaged in aluminum foil laminate bags and heat-sealed. The seed bags were immersed directly into a liquid nitrogen (-196 degrees C) container and stored for one week. Seed bags were warmed overnight at room temperature before starting the germination study. Seed germination and radicle growth were recorded daily. The mean germination time (MGT), seed germination percentage (SGP), germination coefficient of velocity (GCV) and average accumulative radicle growth (AARG) were calculated. SGP responses varied between 65 to 100% after the liquid nitrogen treatment. Cryopreservation significantly reduced MGT values by almost one day as compared to the control treatment. GCV values were higher for all cryopreserved seeds than for control seeds. The AARG data, a measure of seedling vigor, varied from one seed lot to another. It can be concluded that cryopreservation could be a valuable tool to preserve wild bitter apple seeds for their utilization in future breeding programs for abiotic stress tolerance.