Cryostorage of cottonseed with liquid nitrogen

Storage of cottonseed with LN for long periods of time would prevent having to replace valuable germplasm stocks except when they are required for bre eding or research purposes. Seeds of eight cultivars of Gossypium hirsutum L. were stored either above or immersed under liquid nitrogen (LN) and then returned to room temperature and evaluated for quality on the basis of ger mination, vigor, and field development. Storage above LN at 150 degrees C f or 180 days did not appreciably affect germination and vigor and seedlings from the LN-treated seeds appeared normal. Treated and control cottonseed g rown under field conditions had similar stands. The best seed moisture leve ls for LN storage, acccording to germination and vigor tests, were between 4 and 12%. A significant decrease in germination and vigor was observed at moisture levels above 12%. Immersion of cottonseed under LN often caused se vere damage to cotyledons that was apparent during seedling development. Th ese cottonseed germinated well on germination towels after removal from und er LN, but their seedlings often did not grow as well as controls under gro wth chamber conditions. The present cryogenic studies indicate that storage above but not directly in LN may be suitable for long-term preservation of cotton germplasm.